tag:theconversation.com,2011:/ca/topics/physiology-3322/articlesPhysiology – The Conversation2024-02-29T21:48:23Ztag:theconversation.com,2011:article/2228542024-02-29T21:48:23Z2024-02-29T21:48:23ZBetter sleep is a protective factor against dementia<figure><img src="https://images.theconversation.com/files/573581/original/file-20240117-23-vqzz7m.jpg?ixlib=rb-1.1.0&rect=60%2C0%2C6720%2C4456&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lack of sleep, or poor quality sleep, is one of the risk factors for developing Alzheimer's disease. Fortunately, there are ways to improve sleep.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Dementia is a progressive loss of cognitive abilities, such as memory, that is significant enough to have an impact on a person’s daily activities. </p>
<p>It can be caused by a number of different diseases, including <a href="https://alzheimer.ca/en/about-dementia/what-alzheimers-disease">Alzheimer’s</a>, which is the most common form. Dementia is caused by a loss of neurons over a long period of time. Since, by the time symptoms appear, many changes in the brain have already occurred, many scientists are focusing on studying the risk and protective factors for dementia. </p>
<p>A risk factor, or conversely, a protective factor, is a condition or behaviour that increases or reduces the risk of developing a disease, but does not guarantee either outcome. Some risk factors for Alzheimer’s disease and dementia, such as age or genetics, are not modifiable, but there are several other factors we can influence, <a href="https://www.thelancet.com/article/S0140-6736(20)30367-6/fulltext">specifically lifestyle habits and their impact on our overall health</a>.</p>
<p>These risk factors include depression, lack of physical activity, social isolation, high blood pressure, obesity, diabetes, excessive alcohol consumption and smoking, as well as poor sleep.</p>
<p>We have been focusing our research on the question of sleep for over 10 years, particularly in the context of the <a href="https://www.nhlbi.nih.gov/science/framingham-heart-study-fhs">Framingham Heart Study</a>. In this large community-based cohort study, ongoing since the 1940s, the health of surviving participants has been monitored to the present day. As researchers in sleep medicine and epidemiology, we have expertise in researching the role of sleep and sleep disorders in cognitive and psychiatric brain aging. </p>
<p>As part of our research, we monitored and analyzed the sleep of people aged 60 and over to see who did — or did not — develop dementia. </p>
<h2>Sleep as a risk or protective factor against dementia</h2>
<p>Sleep appears to play an essential role in a number of brain functions, such as memory. Good quality sleep <a href="https://jamanetwork.com/journals/jamaneurology/fullarticle/2793873">could therefore play a vital role in preventing dementia</a>.</p>
<p>Sleep is important for maintaining <a href="https://www.science.org/doi/10.1126/science.1241224">good connections in the brain</a>. Recently, research has revealed that sleep seems to have a function similar to that of a garbage truck for the brain: <a href="https://doi.org/10.1016/j.mad.2023.111899">deep sleep could be crucial for eliminating metabolic waste from the brain</a>, including clearing certain proteins, such as those known to accumulate in the brains of people with Alzheimer’s disease. </p>
<p>However, the links between deep sleep and dementia still have to be clarified.</p>
<h2>What is deep sleep?</h2>
<p>During a night’s sleep, we go through several <a href="http://ceams-carsm.ca/en/a-propos-du-sommeil/">sleep stages</a> that succeed one another and are repeated. </p>
<p>NREM sleep (non-rapid eye movement sleep) is divided into light NREM sleep (NREM1 stage), NREM sleep (NREM2 stage) and deep NREM sleep, also called slow-wave sleep (NREM3 stage). The latter is associated with several restorative functions. Next, REM sleep (rapid eye movement sleep) is the stage generally associated with the most vivid dreams. An adult generally spends around 15 to 20 per cent of each night in deep sleep, if we add up all the periods of NREM3 sleep. </p>
<p>Several sleep changes are common in adults, such as going to bed and waking up earlier, sleeping for shorter periods of time and less deeply, and waking up more frequently during the night.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=279&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=279&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=279&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=350&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=350&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579041/original/file-20240229-16-efo9mx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=350&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sleep stages, and the role of deep sleep for brain health.</span>
<span class="attribution"><span class="source">(Andrée-Ann Baril)</span></span>
</figcaption>
</figure>
<h2>Loss of deep sleep linked to dementia</h2>
<p>Participants in the <a href="https://jamanetwork.com/journals/jamaneurology/fullarticle/2810957">Framingham Heart Study</a> were assessed using a sleep recording — known as polysomnography — on two occasions, approximately five years apart, in 1995-1998 and again in 2001-2003. </p>
<p>Many people showed a reduction in their deep slow-wave sleep over the years, as is to be expected with aging. Conversely, the amount of deep sleep in some people remained stable or even increased. </p>
<p>Our team of researchers from the Framingham Heart Study followed 346 participants aged 60 and over for a further 17 years to observe who developed dementia and who did not. </p>
<p>Progressive loss of deep sleep over time was associated with an increased risk of dementia, whatever the cause, and particularly Alzheimer’s type dementia. These results were independent of many other risk factors for dementia.</p>
<p>Although our results do not prove that loss of deep sleep causes dementia, they do suggest that it could be a risk factor in the elderly. Other aspects of sleep may also be important, such as its duration and quality. </p>
<h2>Strategies to improve deep sleep</h2>
<p>Knowing the impact of a lack of deep sleep on cognitive health, what strategies can be used to improve it? </p>
<p>First and foremost, if you’re experiencing sleep problems, it’s worth talking to your doctor. Many sleep disorders are underdiagnosed and treatable, particularly through behavioural (i.e. non-medicinal) approaches. </p>
<p>Adopting good sleep habits can help, such as going to bed and getting up at consistent times or avoiding bright or blue light in bed, like that of screens. </p>
<p>You can also avoid caffeine, limit your alcohol intake, maintain a healthy weight, be physically active during the day, and sleep in a comfortable, dark and quiet environment.</p>
<p>The role of deep sleep in preventing dementia remains to be explored and studied. Encouraging sleep with good lifestyle habits could have the potential to help us age in a healthier way.</p><img src="https://counter.theconversation.com/content/222854/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrée-Ann Baril received funding from the Sleep Research Society Foundation, the Alzheimer Society of Canada, the Canadian Institutes of Health Research, Banting Postdoctoral Fellowships, the Fondation de l'Hôpital du Sacré-Coeur de Montréal, the Université de Montréal and speaking fees from Eisai.</span></em></p><p class="fine-print"><em><span>Matthew Pase received funding from the National Health and Medical Research Council of Australia, National Institute on Aging, Dementia Australia, Alzheimer's Association, National Heart Foundation of Australia, Australian Research Council, Stroke Foundation, Brain Foundation, Alzheimer's Drug Discovery Foundation, Rebecca L Cooper Medical Research Foundation, and Bethlehem Griffiths Research Foundation.</span></em></p>Sleep appears to play an essential role in a number of brain functions, such as memory. So good quality sleep could play a vital role in preventing dementia.Andrée-Ann Baril, Professeure-chercheure adjointe au Département de médecine, Université de MontréalMatthew Pase, Associate Professor of Neurology and Epidemiology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189982024-01-24T13:29:56Z2024-01-24T13:29:56ZPictures have been teaching doctors medicine for centuries − a medical illustrator explains how<figure><img src="https://images.theconversation.com/files/565002/original/file-20231211-30-bxjrr5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1524%2C1770&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artists reveal what cannot be seen.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/internetarchivebookimages/17573010234">Henry Gray, Anthony Edwward Spitzka/Internet Archive via Flickr</a></span></figcaption></figure><p>“Medical illustrators draw what can’t be seen, watch what’s never been done, and tell thousands about it without saying a word.”</p>
<p>For decades, this slogan <a href="https://web.archive.org/web/20070203080223/http://www.ami.org/ECOMAMI/timssnet/common/tnt_frontpage.cfm">appeared on the website</a> and printed materials of the <a href="https://ami.org">Association of Medical Illustrators</a>. Although the association no longer uses this tag line, it’s still an accurate description of the profession.</p>
<p>As a <a href="https://www.rit.edu/directory/japfaa-james-perkins">practicing medical illustrator</a> for over 30 years, I draw what can’t be seen and watch what’s never been done on a daily basis. And I teach my students to do the same. </p>
<p>But what exactly does all of that mean, and how does it improve medicine?</p>
<h2>Tell thousands about it without saying a word</h2>
<p>You may have heard the adage, “A picture is worth a thousand words.” In that same vein, medical illustrators use pictures to teach complex scientific concepts. As the famed medical illustrator <a href="https://www.netterimages.com/artist-frank-h-netter.html">Frank H. Netter</a> once said, “(Pictures) eliminate the need for the lecturer or the author to translate what he has in his mind into words and for the listener or the student to translate those words back into a mental image.”</p>
<p>The use of illustrations to communicate medical information has a long history, dating back at least to <a href="https://doi.org/10.1002/(SICI)1098-2353(1999)12:2%3C120::AID-CA7%3E3.0.CO;2-V">ancient Egypt</a> and flourishing in the Renaissance. The work of 16th century anatomists <a href="https://doi.org/10.3389%2Ffnana.2019.00011">Giacomo Berengario da Carpi</a> and <a href="https://doi.org/10.5339%2Fgcsp.2015.66">Andreas Vesalius</a> set a precedent for the use of detailed illustrations to teach anatomy, a practice that continues to this day.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration depicting the musculature of the human body with text identifying each component" src="https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=820&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=820&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=820&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1031&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1031&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1031&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is a page from Andreas Vesalius’ ‘Suorum de humani corporis fabrica librorum epitome.’</span>
<span class="attribution"><a class="source" href="https://wellcomecollection.org/works/g6b6smge/images?id=w5d9ed8q">Andreas Vesalius/Wellcome Collection</a></span>
</figcaption>
</figure>
<p>The proliferation of illustrated anatomy atlases in the Renaissance coincided with the widespread acceptance of <a href="https://doi.org/10.5115%2Facb.2015.48.3.153">cadaver dissection</a>. The earliest known human dissections were performed in the third century BCE. The practice was prohibited throughout the Middle Ages but became common again in the 13th and 14th centuries. </p>
<p>By the 1500s, dissections, usually of executed criminals, had become public spectacles. The demand for bodies eventually outstripped the supply of executed convicts, leading to the unscrupulous practices of grave robbing and even murder.</p>
<p>In addition to depicting the location and features of an object such as an organ, illustrations proved essential in describing events happening over time, such as the progression of a disease or the steps in a surgical procedure. Generations of surgeons learned new procedures from meticulously illustrated surgical atlases. An early example of physiology illustration, William Harvey’s classic 17th century work on the circulation of blood, “<a href="https://library.si.edu/digital-library/book/exercitatioanat00harv">Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus</a>,” depicts the direction of blood flow through the veins of the forearm.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration showing an arm gripping a pole with a tourniquet wrapped around the elbow." src="https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This image from William Harvey’s ‘Exercitatio’ depicts the direction of normal blood circulation.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:William_Harvey_(1578-1657)_Venenbild.jpg">William Harvey/Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>Nowadays, surgeons can practice a procedure hundreds of times <a href="https://theconversation.com/why-virtual-reality-wont-replace-cadavers-in-medical-school-67448">in virtual reality</a> before trying it on a real patient. Modern physiology and pathology texts include countless illustrations of the body, not just at the anatomical level but also the cellular and molecular. So valuable are these depictions of complex pathways and interactions that many science journals now require papers to include a <a href="https://doi.org/10.7759/cureus.45762">graphical abstract</a>, a single illustration that summarizes the content of each paper.</p>
<h2>Draw what can’t be seen</h2>
<p>Medical illustrators employ special tools and training to visualize things that are normally hidden from the naked eye. </p>
<p>All professionally trained medical illustrators <a href="https://ami.org/medical-illustration/enter-the-profession/careers">study human gross anatomy</a>, including dissecting a human cadaver, in order to visualize the internal structures of the body. When a cadaver isn’t readily available to serve as reference for an illustration, illustrators use <a href="https://doi.org/10.1148/rg.2018170088">medical imaging</a>, such as CT and MRI scans, and reconstruct the body in three dimensions.</p>
<p>At the cellular level, medical illustrators must understand how to use <a href="https://theconversation.com/seeing-what-the-naked-eye-cant-4-essential-reads-on-how-scientists-bring-the-microscopic-world-into-plain-sight-211666">microscopy techniques</a> in order to find references for accurate depictions of cellular structures. </p>
<p>Objects at the smallest scale – atoms and many molecules – are smaller than the wavelength of visible light. This means they are <a href="https://www.purdue.edu/uns/html4ever/1998/9804.Crystallography.html">below the theoretical limit</a> of what can be seen, even with the most powerful light microscope. So researchers experimentally determine the structures of molecules using techniques like <a href="https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Instrumentation_and_Analysis/Diffraction_Scattering_Techniques/X-ray_Crystallography">X-ray crystallography</a> and <a href="https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Spectroscopy/Nuclear_Magnetic_Resonance_Spectroscopy">nuclear magnetic resonance spectroscopy</a> instead. These techniques use X-rays or radio waves, respectively, to determine how atoms are arranged.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="CDC illustration of COVID-19 virus" src="https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This illustration, created by the Centers for Disease Control and Prevention, depicts the notorious spiked structure of the virus that causes COVID-19.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=23311">Alissa Eckert, MSMI; Dan Higgins, MAMS via CDC</a></span>
</figcaption>
</figure>
<p>Medical illustrators learn to locate and retrieve data on the structure of molecules from sites like the <a href="https://www.rcsb.org">RCSB Protein Databank</a>. They also use a host of visualization applications and software plug-ins to render these structures in 3D.</p>
<p>Medical illustrators Alissa Eckert and Dan Higgins at the U.S. Centers for Disease Control and Prevention used these techniques to create the famous <a href="https://phil.cdc.gov/Details.aspx?pid=23311">red-spiked coronavirus image</a> that went viral during the pandemic.</p>
<h2>Watch what’s never been done</h2>
<p>Obviously, you can’t really watch something that has never been done. But medical illustrators can help conceptualize new processes and techniques before they become a reality. </p>
<p>For example, they might illustrate how an experimental drug may theoretically work before it enters testing. Similarly, illustrations can be critically important in <a href="https://doi.org/10.7759%2Fcureus.40841">pre-surgical planning</a>, especially in complex cases.</p>
<p>My favorite example of the role of medical illustration in surgery is the separation of conjoined twins Abbigail and Isabelle Carlsen at the Mayo Clinic in 2006. Working from <a href="https://dl.acm.org/doi/10.1145/1401032.1401099">nearly 6,000 radiographic images</a>, the clinic’s medical illustrators produced five detailed illustrations of the twins’ anatomy. They even generated 3D-printed models of important structures, notably their shared liver. </p>
<p>The illustrations were critical in training a team of 70 surgeons, nurses and technicians involved in the case. They also served as a road map for the ultimately successful surgery, hung up on the walls of the operating theater during the procedure.</p>
<h2>Road to becoming a medical illustrator</h2>
<p>In order to draw what can’t be seen and watch what’s never been done, medical illustrators require specialized training. Most medical illustrators in North America are trained at <a href="https://ami.org/medical-illustration/enter-the-profession/education/graduate-programs">master’s programs</a> accredited by the Association of Medical Illustrators in conjunction with the Commission on Accreditation of Allied Health Education Programs. </p>
<p>Since the profession requires a strong understanding of the biomedical sciences, students accepted into these programs must have a <a href="https://ami.org/medical-illustration/enter-the-profession/education">strong science background</a> along with a portfolio demonstrating outstanding drawing skills. Students often have a double major in biology and art or a major in one area and minor in the other. </p>
<p>Once in the program, their science training continues with human gross anatomy and some combination of courses in neuroanatomy, embryology, histology, cell biology, pathology and immunology. Specialized courses in surgical observation and cellular and molecular visualization also include significant science content. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/7AEDUteTegw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Scientific illustrator Val Altounian of the journal Science walks viewers through her process.</span></figcaption>
</figure>
<p>Students receive extensive training in <a href="https://ami.org/medical-illustration/enter-the-profession/education">computer graphics</a>, including 2D digital illustration and animation, 3D computer modeling and animation, interactive media, virtual and augmented reality and educational game and mobile app design. Courses also emphasize the principles of design, including the use of color, layout and motion to create effective visuals. </p>
<p>Medical illustrators learn to <a href="https://www.wired.com/story/in-a-pandemic-medical-illustrators-made-science-accessible/">consider the educational level of their audience</a>, since their work may be used to educate patients – even kids – in addition to medical professionals. Illustrations made for a child recently diagnosed with leukemia would be very different from those aimed at the oncologist treating the disease.</p>
<p>After entering the workforce, many medical illustrators pursue optional board certification to become a <a href="https://www.ami.org/medical-illustration/board-certification">certified medical illustrator</a>, which recognizes professional competency and encourages continued learning. Continued certification requires 35 hours of continuing education every five years in the biomedical sciences, artistic techniques and business practices. </p>
<p>All of this education and training is essential to ensure that medical illustrators communicate complex scientific information with accuracy and clarity. I like to think of medical illustrators as teachers – they instruct with pictures.</p><img src="https://counter.theconversation.com/content/218998/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James A. Perkins is a Professional Member of the Association of Medical Illustrators. </span></em></p>From body snatching to Photoshop and virtual reality, the techniques of medical illustration have evolved. But its essential role in showing clinicians how to care for the body continues today.James A. Perkins, Distinguished Professor of Medical Illustration, Rochester Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2150842023-12-06T03:01:41Z2023-12-06T03:01:41ZIt’s extremely hot and I’m feeling weak and dizzy. Could I have heat stroke?<figure><img src="https://images.theconversation.com/files/562631/original/file-20231130-15-dos5eb.jpg?ixlib=rb-1.1.0&rect=0%2C53%2C5991%2C3934&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/middleaged-caucasian-man-cooling-off-electric-2025203906">Shutterstock</a></span></figcaption></figure><p>Australia is braced for a hot, dry summer. El Nino is back, and this year it will occur alongside an <a href="https://www.abc.net.au/news/2023-08-22/positive-indian-ocean-dipole-to-coincide-with-el-nino/102756378">Indian Ocean dipole</a>, a climate pattern which will further amplify this hot and dry effect. </p>
<p>Hot weather can place great stress on our bodies. When the environmental conditions exceed the limit at which we can adequately cope, we can suffer from heat-related illnesses.</p>
<p>Heat illnesses can vary, from relatively mild heat exhaustion to the potentially life-threatening condition of heat stroke.</p>
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Read more:
<a href="https://theconversation.com/extreme-weather-is-landing-more-australians-in-hospital-and-heat-is-the-biggest-culprit-216440">Extreme weather is landing more Australians in hospital – and heat is the biggest culprit</a>
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<h2>What are the signs and symptoms?</h2>
<p>If you’re suffering from heat exhaustion, you may feel weakness, nausea, headaches or dizziness.</p>
<p>Mild <a href="https://www.health.nsw.gov.au/environment/beattheheat/Pages/heat-related-illness.aspx">symptoms of heat exhaustion</a> can often be treated at home by reducing your levels of physical activity, finding shade, removing excess clothing, hydrating with water and perhaps even taking a cool shower.</p>
<p>If left unchecked, heat exhaustion can progress to the far more serious condition of heat stroke, where your core temperature climbs upwards of 40°C. <a href="https://www.health.nsw.gov.au/environment/beattheheat/Pages/heat-related-illness.aspx">Symptoms</a> can develop rapidly and may include confusion, disorientation, agitation, convulsions, or it could even result in a coma.</p>
<p>Heat stroke is a medical emergency and requires urgent treatment. Call an ambulance and start rapid, aggressive cooling by immersing the person in cold water (such as a cold bath). If this isn’t possible, apply ice packs to their neck, armpits and groin and cover the skin with lots of cool water. </p>
<p>When it comes to cooling someone with suspected heat stroke, the quicker the better: cool first, transport second.</p>
<h2>Why do we overheat?</h2>
<p>Environmental conditions play an important role in determining our heat stress risk. If the air temperature, humidity and levels of sun exposure are high, we are much more likely to dangerously overheat. </p>
<p>When the body gets hot, the heart pumps more warm blood to our skin to help lose heat. As air temperature rises, this way of shedding heat becomes ineffective. When air temperature is higher than the temperature of the skin (normally around 35°C), we start gaining heat from our surroundings.</p>
<p>Sweating is by far our most effective physiological means of keeping cool. However, it is the <em>evaporation</em> of sweat from our skin that provides cooling relief. </p>
<p>When the air is humid, it already contains a lot of moisture, and this reduces how efficiently sweat evaporates.</p>
<p>Our physical activity levels and clothing also impact heat stress risk. When we move, our bodies generate metabolic heat as a by-product. The more intense physical activity is, the more heat we must lose to avoid dangerous rises in core temperature. </p>
<p>Finally, clothing can act as an insulator and barrier for the evaporation of sweat, making it even more difficult for us to keep cool.</p>
<h2>Who is most vulnerable in the heat?</h2>
<p>Some people <a href="https://www.health.nsw.gov.au/environment/beattheheat/Pages/people-most-at-risk.aspx">are at greater risk</a> of developing heat illness than others. This can result from physiological limitations, such as a decreased capacity to sweat, or a reduced capacity to adapt our behaviour. When these two risk factors coincide, it’s a perfect storm of vulnerability.</p>
<p>Take, for example, an elderly outdoor agricultural worker. Being aged over 60, their physiological capacity to sweat is reduced. The worker may also be wearing heavy safety clothing, which may further limit heat loss from the body. If they don’t slow down, seek shelter and adequately hydrate, they become even more vulnerable.</p>
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Read more:
<a href="https://theconversation.com/5-reasons-to-check-on-your-elderly-neighbour-during-a-heatwave-196218">5 reasons to check on your elderly neighbour during a heatwave</a>
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<p>When a person dies of heat stroke – which is relatively easy to diagnose – heat will be listed as a cause of death on a death certificate. Between 2001 and 2018 in Australia, 473 heat-related deaths were <a href="https://www.sciencedirect.com/science/article/pii/S2212420921006324">officially reported</a>.</p>
<p>However, the true association between heat and death is thought to be far greater, with an <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(20)30100-5/fulltext">estimated 36,000 deaths</a> in Australia between 2006 and 2017.</p>
<p>This is because most people who die during extreme heat events do not die from heat stroke. Instead, they they die of <a href="https://www.nejm.org/doi/full/10.1056/nejm199607113350203">other medical complications</a> such as cardiovascular or renal collapse, as additional strain is placed on essential organs such as the heart and kidneys.</p>
<p>People with underlying health conditions are more likely to succumb to heat-associated complications before they develop critical core temperature (over 40°C) and heat stroke. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1681178776170905600"}"></div></p>
<p>In such cases, while the additional physiological strain imposed by the heat probably “caused” the death, the official “cause of death” is often listed as something else, such as a heart attack. This can make understanding the true health burden of extreme heat more difficult. </p>
<h2>How to stay safe in the heat</h2>
<figure class="align-center ">
<img alt="Cold shower" src="https://images.theconversation.com/files/563202/original/file-20231204-29-2rftik.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563202/original/file-20231204-29-2rftik.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563202/original/file-20231204-29-2rftik.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563202/original/file-20231204-29-2rftik.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563202/original/file-20231204-29-2rftik.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563202/original/file-20231204-29-2rftik.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563202/original/file-20231204-29-2rftik.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Having a cool shower can cool you down.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/black-shower-head-switched-on-161502/">Pexels/Pixabay</a></span>
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<p>Thankfully, there are effective, low-cost <a href="https://twitter.com/TheLancet/status/1677702906789740545">ways</a> of staying safe in the heat. These include: </p>
<ul>
<li>staying adequately hydrated </li>
<li>getting out of the heat to a cooler area indoors or shaded area outdoors</li>
<li>loosening or removing clothing</li>
<li>cooling down any way you can:
<ul>
<li>using an electric fan (which can be used at 37°C and below, irrespective of age and humidity)<br></li>
<li>using a cold-water spray</li>
<li>applying a cool, damp sponge or cloth</li>
<li>wetting clothes and skin</li>
<li>having a cool shower or bath</li>
<li>applying ice packs or crushed ice in a damp towel on the neck, groin and armpits.</li>
</ul></li>
</ul>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/top-10-tips-to-keep-cool-this-summer-while-protecting-your-health-and-your-budget-193723">Top 10 tips to keep cool this summer while protecting your health and your budget</a>
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<img src="https://counter.theconversation.com/content/215084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Smallcombe receives funding from National Health and Medical Research Council (NHMRC) and the Wellcome Trust.</span></em></p><p class="fine-print"><em><span>Ollie Jay receives funding from National Health and Medical Research Council, Wellcome Trust, NSW Health, NSW Dept of Planning, Industry and Environment, and the NSW Reconstruction Authority (formerly Resilience NSW), Tennis Australia.</span></em></p><p class="fine-print"><em><span>Lily Hospers does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Heat illnesses can vary, from relatively mild heat exhaustion to the potentially life-threatening condition of heat stroke. Here’s how to tell the difference.Lily Hospers, PhD Candidate, University of SydneyJames Smallcombe, Post-doctoral Research Associate, University of SydneyOllie Jay, Professor of Heat & Health; Director of Heat & Health Research Incubator; Director of Thermal Ergonomics Laboratory, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2169502023-11-10T13:25:12Z2023-11-10T13:25:12ZSpecialized training programs using sensory augmentation devices could prevent astronauts from getting disoriented in space<figure><img src="https://images.theconversation.com/files/558127/original/file-20231107-15-nnyzbl.jpg?ixlib=rb-1.1.0&rect=8%2C5%2C1941%2C1075&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Astronauts prepare to leave the International Space Station.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/SpaceStation/ab2eaca4b8b84b04a961488995ab42f4/photo?Query=space%20flight&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=570&currentItemNo=NaN&vs=true&vs=true">NASA via AP</a></span></figcaption></figure><p>When landing on the surface of the Moon, astronauts can become spatially disoriented, which is when they lose sense of their orientation – they might not be able to tell which way is up. This disorientation can lead to fatal accidents. </p>
<p>Even on Earth, <a href="https://doi.org/10.3357/ASEM.3971.2014">between 1993 and 2013</a>, spatial disorientation led to the loss of 65 aircraft, US$2.32 billion of damages and 101 deaths in the U.S.</p>
<p>Could wearable technology augment the senses of astronauts, allowing them to overcome the limitations of their biological sensors? And what type of training could build a deeper bond between the astronaut and the wearable technology, so that astronauts would be able to rely on the technology when they can’t trust their own senses?</p>
<p><a href="https://sites.google.com/view/vivekanandpandeyvimal/research_2/introduction">I am a research scientist</a> in the <a href="https://www.brandeis.edu/graybiel/">Ashton Graybiel Spatial Orientation Lab</a> at <a href="https://www.brandeis.edu/">Brandeis University</a>. With my collaborators, <a href="https://scholar.google.com/citations?user=YmkwkIEAAAAJ&hl=en">Alexander Panic</a>, <a href="https://scholar.google.com/citations?user=B1INHVwAAAAJ&hl=en">James Lackner</a> and <a href="https://scholarworks.brandeis.edu/esploro/profile/paul_dizio/overview">Paul DiZio</a>, I study sensory augmentation and spatial disorientation, which is when astronauts and pilots lose the sense of which way they are oriented. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/4uTpHzZdDeE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Spatial disorientation research may help astronauts in the future, and it can have applications for other fields, like vestibular disorders.</span></figcaption>
</figure>
<p><a href="https://doi.org/10.3389/fphys.2023.1249962">In a paper</a> published in November 2023 in Frontiers in Physiology, we determined whether vibrotactors – small vibrating devices placed on the skin – could enhance the performance of participants put in a disorienting condition that mimicked spaceflight. We also studied what type of training could enhance the connection between the human and the device. </p>
<p>Vibrotactors communicate information through the touch receptors of the somatosensory system instead of the visual system. They have previously helped pilots <a href="https://doi.org/10.1177/154193120004400148">flying helicopters</a> and <a href="https://doi.org/10.1109/51.827409">airplanes</a>.</p>
<p>When pilots are disoriented, their visual system often gets <a href="https://doi.org/10.3357/ASEM.3048.2011">overwhelmed with information</a>. Vibrotactors can help because they send touch signals rather than visual signals.</p>
<h2>Creating a spaceflight analog condition</h2>
<p>For our first experiment, we wanted to figure out whether using vibrotactors would improve a particpant’s ability to stabilize themselves in a disorienting spaceflight condition. </p>
<p>We strapped participants into a multi-axis rotation device, which is a machine containing a chair that’s programmed to behave like an inverted pendulum. Like a pencil falling left or right as you try to balance it on your fingertip, the multi-axis rotation device tilts to the left or right. Participants used a joystick to try to balance themselves and keep the chair upright. </p>
<p>We blindfolded the participants, because spatial disorientation often occurs when pilots can’t see – like when they <a href="https://apps.dtic.mil/sti/citations/ADP013844">fly at night or through clouds</a>. </p>
<p>On Earth, tiny organs in the inner ears <a href="https://www.ncbi.nlm.nih.gov/books/NBK10792/">called otoliths</a> help people keep their balance by sensing how far the body is tilted away from an upright position, also called the gravitational vertical. In space and especially during gravitational transitions, such as while landing on a planet or the Moon, the gravitational information detected by the otoliths is very different than on Earth. This can cause disorientation. </p>
<p>Additionally, <a href="https://doi.org/10.1152/jn.00476.2019">long-duration spaceflight</a> will change how the brain interprets the signals coming from the otoliths. This can also lead to disorientation when landing. </p>
<p>In our Earth analog condition, which was meant as a control to compare against the spaceflight condition we tested, participants sat in the multi-axis rotation device and used a joystick to stabilize themselves around the balance point. The balance point was at an upright position, or the gravitational vertical. </p>
<p>Because the otoliths can sense tilt from the gravitational vertical, participants always had a good sense of their orientation and the location of the balance point. We called this the Earth analog condition because they could use gravitational cues to do the task. <a href="https://doi.org/10.1007/s00221-017-5068-3">Every participant learned and improved</a> their performance on this over time. </p>
<p>Then, in the spaceflight analog condition, we had the multi-axis rotation device pitch the participants back by 90 degrees. The balance point was still in the center, and the multi-axis rotation device was programmed to tilt to either the left or right while participants were on their back. </p>
<p>In the Earth condition, the balance point was lined up with the upright, so it was easy to use the otoliths to determine how much one was tilted. However, in the spaceflight condition, participants no longer tilted relative to the gravitational vertical, because they were always on their back. So even though the balance point they were trying to find was the same, they could no longer use gravity to determine how much they were tilted from the balance point.</p>
<p>Similarly, astronauts have minimal gravitational cues when initially landing. <a href="https://doi.org/10.1007/s00221-017-5068-3">In our spaceflight condition</a>, the participants showed very poor performance and had high rates of losing control.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two photos, the left labeled 'Vertical roll plane' shows a participant strapped into a chair that's tilted with his head to the right and feet to the left, but oriented upright. The right, lableled 'horizontal roll plane' shows the participant tilted back" src="https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=275&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=275&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=275&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=346&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=346&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557559/original/file-20231103-23-l58q3k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=346&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In the Earth analog condition, participants balance in the upright vertical plane, while in the spaceflight analog condition, participants are tilted back and they balance in the horizontal plane. There, they can no longer use gravitational information to figure out where they are.</span>
<span class="attribution"><span class="source">Ashton Graybiel Spatial Orientation Lab</span></span>
</figcaption>
</figure>
<p>For each of the 13 participants in the experimental group, we attached four vibrotactors on each arm. The farther a participant titled from the balance point, the more vibrotactors vibrated on the same side. </p>
<p><a href="https://doi.org/10.3389/fphys.2023.1249962">We found</a> that vibrotactile feedback helped performance in the disorienting spaceflight condition. But it also led to a feeling of conflict between a participant’s incorrect perception of their orientation and their actual orientation, as indicated by the vibrotactors. </p>
<p>Because of this conflict, the participants’ performance in the spaceflight condition <a href="https://doi.org/10.3389/fphys.2023.1249962">was not as good</a> as it was in the Earth condition.</p>
<p>Surprisingly, even knowing that they were disoriented and reporting high levels of trust in the vibrotactors was not enough to allow people to continue learning and improving their performance. This suggests that cognitive trust, or their self-reported level of trust, may differ than their gut-level trust – and cognitive trust alone <a href="https://doi.org/10.3389/fphys.2023.1249962">does not ensure</a> people will be able to rely on the vibrotactors when disoriented.</p>
<h2>Building a human-device bond</h2>
<p>Previous <a href="https://doi.org/10.1016/j.tics.2003.10.013">research in sensory substitution</a> has found that allowing participants to freely explore and play around with the device during training builds a bond between the human and the device.</p>
<p>In our first experiment, we provided participants with time to explore how the device works. We gave them 40 minutes to explore the vibrotactile feedback in the Earth condition the day before they were tested in the spaceflight condition. While this helped participants perform better than those who did not have vibrotactors, <a href="https://doi.org/10.3389/fphys.2023.1249962">their improvements were modest</a>, and these participants did not show any further improvement in performance after being given 40 minutes in the spaceflight condition. </p>
<p>So, why was this free exploration not enough for our test condition but sufficient for other experiments? One reason could be that the majority of prior studies on sensory augmentation have had the training and testing occur in the same environment. However, astronauts will most likely receive their training on Earth before being in space, where their sensory information will be very different. </p>
<p>To determine whether specialized training could lead to better results, we ran another group of participants <a href="https://doi.org/10.1007/s00221-019-05631-x">through a training program</a>. </p>
<p>Participants spent the first day in the Earth analog condition, where they had to stabilize themselves while searching for hidden balance points that were different than the upright, or gravitational vertical. In order to find the hidden balance point, they had to disengage from their desire to align with the upright while focusing on the vibrotactors, which indicated the location of the balance point.</p>
<p>When this group was tested on Day 2 in the spaceflight analog condition, they <a href="https://doi.org/10.3389/fphys.2023.1249962">performed significantly better</a> than the group that had the vibrotactors but hadn’t received the training program. Our findings suggest that simple exposure to sensory augmentation devices will be not be enough training for astronauts to rely on the device when they cannot rely upon their own senses. </p>
<p>Also, cognitive trust in the device may not be enough to ensure reliance. Instead, astronauts will need specialized training that requires disengaging from one sense while focusing on feedback from the device.</p><img src="https://counter.theconversation.com/content/216950/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vivekanand Vimal receives funding from NASA’s Human Research Program under grant 80NSSC22K0758</span></em></p>When you’re an astronaut landing on the Moon, you can’t rely on the same gravitational cues we have on Earth. But regimented training with sensory devices could one day prevent spatial disorientation.Vivekanand Pandey Vimal, Research Scientist, Brandeis UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2165892023-11-01T17:04:03Z2023-11-01T17:04:03ZThe best techniques for being a cricket fast bowler, according to science<p>Twenty years ago, Shoaib Akhtar became the <a href="https://www.espncricinfo.com/story/shoaib-akhtar-at-100-mph-126897">first person recorded to bowl at 100mph (161km per hour)</a> during the 2003 One-Day International Men’s World Cup match for Pakistan against England. There was an expectation afterwards that this feat would become a regular occurrence.</p>
<p>As humans have continued to run faster, throw further and jump higher, it was believed that this milestone would be a stepping stone consigned to history similar to Roger Bannister <a href="https://www.guinnessworldrecords.com/records/hall-of-fame/first-sub-four-minute-mile">breaking the four-minute mile</a>. It was thought it might also act as a catalyst for serious worldwide improvement in fast bowling.</p>
<p>However, despite continuing improvement in the athletic ability of fast bowlers, the magical three-figure barrier has only been surpassed since by Brett Lee and Shaun Tait – and not for over ten years.</p>
<p>Has cricket fast bowling’s top speed stalled? During the current <a href="https://www.cricketworldcup.com/">2023 One-Day International Men’s World Cup</a> being hosted in India, only a handful of bowlers have produced speeds over 90mph (145km per hour), with the fastest being around 95mph (153 km per hour).</p>
<p>The performance of cricket fast bowlers almost entirely depends on two factors. The first is the amount of momentum developed in the run-up and maintained before the front foot contacting the floor. The second is the technique employed to generate and transfer momentum within the body <a href="https://en.wikipedia.org/wiki/Bowling_action#/media/File:Bowling_action.png">during the bowling phase</a> between the front foot contacting the floor and the release of the ball from the bowler’s hand. </p>
<p><a href="https://journals.humankinetics.com/view/journals/jab/29/1/article-p78.xml">Previous research</a> has highlighted that the fastest elite male bowlers generate more momentum in their run-up, adopting a movement strategy that aims to maintain and transfer this momentum into the throw instead of generating additional momentum from their muscles.</p>
<h2>Testing the limits</h2>
<p>To investigate the limits of fast bowling performance, a <a href="https://linkinghub.elsevier.com/retrieve/pii/S0021929023003354">world-leading predictive musculoskeletal computer simulation model</a> of ten elite male fast bowlers (essentially a virtual clone of each bowler) was developed. It then optimised their technique to maximise the release speed of the ball. </p>
<p>Significantly, none of these bowlers were predicted by the computer model to break the 100mph barrier.</p>
<p>To understand why the top speed has stalled, it is important to consider how all the factors influencing human movement patterns affect the technique of fast bowlers. </p>
<p><a href="https://link.springer.com/article/10.2165/00007256-200333040-00001">The behaviour of all our movement patterns</a> is shaped by three types of constraint. The first is organismic: these are constraints on the individual, such as their size, strength and range of motion. The second factor shaping movement patterns is the environment the individual interacts with, including the atmosphere, temperature, equipment and surfaces. The third shaping factor is the task, which involves constraints such as the goal of the activity, the rules and the intensity. </p>
<p>Our previous experiences of the movement – what we have seen, what we have been told and our previous performance of the movement – also affect individual technique in fast bowling.</p>
<p>The innate physiology of the fast bowler, an organismic constraint, provides the only potential area for development in fast bowling. The other constraints, such as environment and task, which often lead to scientific and technological development associated with improvements in other sports, are extremely limited in fast bowling. This is due to the lack of equipment and the simplicity of the activity.</p>
<p>The physiological aspect often considered to be associated with improvements in fast bowling performance is an increase in muscular strength, power and endurance. However, there’s a unique cricket bowling “task” constraint which requires bowlers to maintain a straight arm during the bowling phase. This significantly reduces the time available to complete the throwing movement. </p>
<h2>Explosive activation</h2>
<p>Elite males <a href="https://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1522700">complete the bowling phase in approximately 100 milliseconds</a>. This is similar to the time required to explosively activate a single muscle. This limits the ability of bowlers to develop additional momentum using their muscles in the bowling phase and neutralises the effect of strength increases on ball speed. </p>
<p>This explains why maximising momentum generated during the run-up is preferred over generating muscular momentum during the bowling phase. It also explains why fast bowling top speeds have not increased despite recent advances in fast bowlers’ athletic abilities.</p>
<p>Interestingly, <a href="https://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1522700">research on women fast bowlers</a> has highlighted that bowlers who generate less momentum during the run-up and therefore have more time available to generate additional muscular momentum, adopt a movement pattern <a href="https://journals.assaf.org.za/index.php/sajsm/article/view/15080">more akin to throwing</a>. In this approach, the momentum generated in the run-up is added to via the use of large rotational torso muscles within the bowling phase. </p>
<p>Improvements to the performance of the large rotational torso muscles in men and women could possibly improve the generation of muscular momentum. But this approach is considered a sub-optimal technique by the research that’s been carried out on fast bowling.</p>
<p>A potential mechanism to increase the time available to develop more momentum from muscles would be to increase the range of motion that joints move through during the bowling phase. </p>
<h2>Joint ‘hypermobility’</h2>
<p><a href="https://www.tandfonline.com/doi/full/10.1080/02640414.2023.2200520">Recent research has highlighted</a> that, on average, elite fast bowlers with an increased range of motion in the hip and shoulder had greater ball release speeds. It was also suggested that the bowlers’ techniques were probably influenced by their range of motion during their early learning years. </p>
<p>In addition, elbow hyperextension – where the joint travels beyond a straight position – <a href="https://www.tandfonline.com/doi/abs/10.1080/02640414.2015.1137340">has been shown to increase the speed of ball release</a> by up to 5% during the bowling phase. A common misconception, however, is that taller bowlers will bowl faster due to the benefit associated with increased limb length.</p>
<p>Unfortunately, as limbs get longer, they get more difficult to rotate. As muscular strength does not scale equally with limb length this becomes a disadvantage. Thus, an optimal height for fast bowlers probably exists, though we don’t know what it is.</p>
<p>Organismic factors linked with increased ball speed such as body shape, size and hypermobility are largely genetic. Since human evolution is extremely slow, advances in ball release speed are likely to follow at a similar pace. </p>
<p>The 100mph barrier, therefore, should be viewed more as a mountain that requires a once-every-generation bowler to scale rather than a dam in a river. The potential of this peak to grow is limited by the constraints of the task and by our innate physiology.</p><img src="https://counter.theconversation.com/content/216589/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Felton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Why the speed of fast bowling in cricket seems to have stalled.Paul Felton, Senior Lecturer in Biomechanics in the School of Science and Technology, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2143362023-09-26T19:15:12Z2023-09-26T19:15:12ZWildland firefighters face a huge pay cut without action by Congress – in the midst of strenuous, dangerous work during fire season<figure><img src="https://images.theconversation.com/files/550088/original/file-20230925-21-dqz83f.jpg?ixlib=rb-1.1.0&rect=0%2C20%2C1917%2C1256&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Wyoming Hotshot crew conducts night operations on the Pine Gulch fire in Colorado in August 2020.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/50321123752">Kyle Miller, Wyoming Hotshots, USFS</a></span></figcaption></figure><p>Radios crackle with chatter from a wildfire incident command post. Up the fireline, firefighters in yellow jerseys are swinging <a href="https://en.wikipedia.org/wiki/Pulaski_(tool)">Pulaskis</a>, axlike hand tools, to <a href="https://www.nps.gov/articles/wildland-fire-fireline-construction.htm">carve a fuel break</a> into the land.</p>
<p>By 10 a.m., these firefighters have already hiked 3 miles up steep, uneven terrain and built nearly 1,200 feet of <a href="https://www.nps.gov/articles/wildland-fire-fireline-construction.htm">fireline</a>.</p>
<p>It’s physically exhausting work and essential for protecting communities as wildfire risks rise in a warming world. Hotshot crews like this one, the U.S. Forest Service’s <a href="https://www.fs.usda.gov/detail/lolo/fire/?cid=FSEPRD745300">Lolo Hotshots</a>, are the elite workforce of the forests. When they’re on the fireline, their bodies’ total <a href="https://doi.org/10.1002/cphy.c220016">daily energy demands</a> can rival that of the cyclists in the Tour de France, as my team’s research with wildland fire crews shows.</p>
<figure class="align-center ">
<img alt="A row of firefighters in yellow long-sleeve shirts, heavy packs and helmets hacks away a fireline on a forest slope." src="https://images.theconversation.com/files/550090/original/file-20230925-29-t4mhgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550090/original/file-20230925-29-t4mhgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550090/original/file-20230925-29-t4mhgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550090/original/file-20230925-29-t4mhgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550090/original/file-20230925-29-t4mhgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550090/original/file-20230925-29-t4mhgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550090/original/file-20230925-29-t4mhgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ruby Mountain Hotshots construct a fireline during the Dixie Fire in 2021.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/51434898834">Joe Bradshaw/BLM</a></span>
</figcaption>
</figure>
<p>These firefighters are also caught in Congress’ latest budget battle, where <a href="https://theconversation.com/kevin-mccarthys-leadership-is-an-open-question-as-budget-shutdown-looms-and-gop-infighting-takes-center-stage-213951">demands by far-right House members</a> to slash federal spending could lead to a governmentwide shutdown after the fiscal year ends on Sept. 30, 2023.</p>
<p>After extreme fire seasons in 2020 and 2021, Congress <a href="https://www.whitehouse.gov/briefing-room/statements-releases/2022/06/21/fact-sheet-biden-harris-administration-announces-new-pay-raises-supports-for-wildland-firefighter-workforce-from-bipartisan-infrastructure-law/">funded a temporary bonus</a> that boosted average U.S. Forest Service wildland firefighter pay by either 50% or US$20,000, whichever was lower. But that increase expires after Sept. 30, knocking many federal firefighters back to earning the <a href="https://www.gao.gov/products/gao-23-105517">minimum $15 per hour</a>. </p>
<p><a href="https://www.cbo.gov/publication/59513">Legislation to make the raise permanent</a> is <a href="https://theintercept.com/2023/07/28/kyrsten-sinema-bill-firefighter-pay/">pending before Congress</a>, which is now preoccupied. A <a href="https://www.cnn.com/2023/09/05/politics/congress-wrestles-over-firefighter-pay/index.html">short-term pay boost</a> may be possible, but that doesn’t solve the long-term pay problem. And if the government shuts down, federal firefighters will be working without immediate pay. The National Federation of Federal Employees warns that a large number of <a href="https://www.latimes.com/california/story/2023-09-25/pay-cuts-possible-exodus-of-federal-firefighters">firefighters could quit</a> if their pay also drops.</p>
<h2>Firefighters push their bodies to extremes</h2>
<p>Life on the fireline is demanding. Pack straps dig into the neck and shoulders with each swing of the Pulaski. It’s a constant reminder that everything wildland firefighters need, they carry – all day.</p>
<p>The critical water and food items, supplies, extra gear and fireline tools – Pulaskis, chain saws and fuel – add up to an average gear weight often exceeding 50 pounds.</p>
<p><a href="https://doi.org/10.1016/j.wem.2018.03.006">Hiking with a load</a> and <a href="https://doi.org/10.1071/WF9970069">digging firelines</a> with hand tools burns about 6 to 14 calories per minute. Heart rates rise in response to an increased pace of digging.</p>
<figure class="align-center ">
<img alt="A firefighter in the woods loaded with gear, including chain saw, fuel canister and full backpack." src="https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A Lakeview Hotshots firefighter carries equipment and fuel for containing the Cedar Creek fire near Oakridge, Ore., in 2022.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/hotshot-firefighter-works-to-contain-the-cedar-creek-fire-news-photo/1243179718">Dan Morrison / AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>Measured with the same techniques used to quantify the <a href="http://doi.org/10.1055/s-2007-1024951">energy demands of Tour de France riders</a>, wildland firefighters demonstrate an average total energy expenditure approaching <a href="https://pubmed.ncbi.nlm.nih.gov/12048336/">4,000 to 5,000 calories per day</a>. Some days can <a href="https://doi.org/10.1016/j.wem.2014.12.010">exceed the Tour’s average of about 6,000 calories</a>, equivalent to around 12 <a href="https://www.mcdonalds.com/us/en-us/meal/hamburger-happy-meal.html">McDonald’s Happy Meals</a>. Add to that a <a href="https://doi.org/10.1249/01.MSS.0000089348.39312.4D">daily water need of 1.5</a> to <a href="https://doi.org/10.1016/j.wem.2014.12.010">over 2 gallons</a>.</p>
<p>This isn’t just for a few days. Fire season in the western United States can last five months or more, with most Hotshot crews accumulating four to five times the number of operational days of the 22-day Tour de France and over 1,000 hours of overtime.</p>
<h2>The physical demand of a day on the fireline</h2>
<p>My team has been measuring the physical strain and total energy demands of work on an active wildfire, with the goal of finding ways to improve firefighter fueling strategies and health and safety on the line.</p>
<p>The crew members we work with are outfitted with a <a href="https://equivital.com/mobile-physiological-monitoring">series of lightweight monitors</a> that measure heart rate, as well as movement patterns and speed, using GPS. Each participant swallows a temperature-tracking sensor before breakfast that will record core body temperature each minute throughout the work shift. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dozen firefighters, some leaning on their Pulaski tools, look at a map of the fire. They're standing in a wooded area with tall pines behind them." src="https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Firefighters are often working in rough forest terrain involving long hikes and steep slopes. Here, the Ruby Mountain Hotshot crew gets a briefing on the Dixie Fire in California in 2021.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/51434899564">Joe Bradshaw/BLM</a></span>
</figcaption>
</figure>
<p>As the work shift progresses, the Hotshots constantly monitor their surroundings and <a href="https://doi.org/10.1249/mss.0b013e318040b2fb">self-regulate</a> their <a href="https://doi.org/10.1016/j.wem.2020.01.009">nutrient</a> and <a href="https://doi.org/10.1580/07-WEME-OR-114.1">fluid intake</a>, knowing their shift could last 12 to 16 hours.</p>
<p>During intense activity in high heat, their <a href="https://doi.org/10.1580/07-WEME-OR-114.1">fluid intake</a> can increase to 32 ounces per hour or more.</p>
<p>The highest-intensity activity is generally during the <a href="https://doi.org/10.1016/j.wem.2018.03.006">early morning hike to the fireline</a>. However, the metabolic demands can sharply increase if crews are forced into a rapid <a href="https://www.publish.csiro.au/wf/WF02025">emergency evacuation from the fire</a>.</p>
<p>My <a href="https://doi.org/10.1002/cphy.c220016">team’s research</a> has found that the most effective way for wildland firefighters to stay fueled is to eat small meals frequently throughout the work shift, similar to the patterns perfected by riders in the Tour. This <a href="https://doi.org/10.1093/ajcn/76.1.120">preserves cognitive health</a>, helping firefighters stay focused and sharp for making potentially lifesaving decisions and keenly aware of their ever-dynamic surroundings, and boosts their <a href="https://doi.org/10.1249/mss.0b013e318040b2fb">work performance</a>. It also helps slow the depletion of <a href="https://doi.org/10.1016/j.wem.2010.09.019">important muscle fuel</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Lists of details about wildland firefighter loads like weight, energy demand, water budget, and heart rate." src="https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=566&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=566&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=566&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=712&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=712&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=712&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Resource demands on a wildland firefighter.</span>
<span class="attribution"><span class="source">Christopher Durdle, Brent Ruby</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Although crews gradually <a href="https://doi.org/10.1016/j.jtherbio.2014.08.009">acclimatize to the heat</a> over the season, the risk for <a href="https://doi.org/10.1016/j.wem.2011.01.008">heat exhaustion</a> is ever present if the work rate is not kept in check. This cannot be prevented by simply drinking more water during long work shifts. However, regular breaks and having a strong aerobic capacity provides some protection by <a href="https://doi.org/10.7205/MILMED-D-12-00524">reducing heat stress</a> and overall risk.</p>
<h2>The season takes a toll</h2>
<p>Hotshots are physically fit, and they train for the fire season just as many athletes train for their competition season. Most crew members are hired temporarily during the fire season – typically from <a href="https://www.epa.gov/climate-indicators/climate-change-indicators-wildfires">May to October, but that’s expanding as the planet warms</a>. And there are <a href="https://www.fs.usda.gov/managing-land/fire/safety/wct">distinct fitness requirements for the job</a>. The physical preparations are demanding, take months and are expected, even when temporary crew members are not officially employed by the agencies.</p>
<p>Still, with the immense physical demands of the job, crew members often experience a <a href="https://doi.org/10.1097/JOM.0000000000001535">decay in metabolic and cardiovascular health</a> and an <a href="https://doi.org/10.1097/JOM.0000000000002446">increase in cholesterol, blood lipids and body fat</a>. It is unclear why such a hardworking job often makes firefighters less healthy, requiring an off-season reset to recover, retrain and rebuild.</p>
<p>The season causes damage. This unfolds counter to the commonly accepted benefits of <a href="https://pubmed.ncbi.nlm.nih.gov/25905196/">regular exercise</a>. <a href="https://doi.org/10.1080/08958370600985875">Pollutant and smoke exposure</a>, lapses in <a href="https://doi.org/10.1249/MSS.0b013e31817f4d58">nutrition</a>, <a href="https://doi.org/10.1097/JOM.0000000000001175">sleep disorders</a> and <a href="https://doi.org/10.1080/08039488.2017.1368703">chronic stress</a> during the season seem to gradually poke holes in the Hotshot armor.</p>
<figure class="align-center ">
<img alt="Three firefighters lounge on air mattresses while reading. Tents are behind them, and boots are in the foreground." src="https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">‘Home’ on the firelines is typically groups of tents and air mattresses.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/WesternWildfires/0dff6baed4fb4394a72b99895035a1db/photo">AP Photo/Ted S. Warren</a></span>
</figcaption>
</figure>
<p>Progressive intervention strategies can help, such as educational programs on specific physical training and nutritional needs, mindfulness training to reduce the risk of job-oriented anxiety and depression, and emotional support for crew members and families. However, these require agency and congressional investment, a commitment beyond ensuring pay raises remain intact. Removing either is synonymous with taking away critical tools for the job on the firelines. </p>
<p>Developing offseason practices that pay close attention to both physical and mental health recovery can help limit harm to firefighters’ health. Many Hotshots have bounced back and <a href="https://www.govexec.com/workforce/2023/01/federal-firefighter-groups-find-flaws-watchdogs-conclusions-recruitment-retention-challenges/382428/">returned season after season</a>.
However, a government shutdown and failure to act on pay for front-line fire crews could <a href="https://www.gao.gov/products/gao-23-105517">worsen crew retention in an already dwindling workforce</a>. </p>
<p><em>This is an update to an article originally published <a href="https://theconversation.com/yellow-jerseys-of-the-fireline-a-day-fighting-wildfires-can-require-as-much-endurance-as-riding-the-tour-de-france-201079">Aug. 8, 2023</a>.</em></p><img src="https://counter.theconversation.com/content/214336/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brent C. Ruby receives funding from a wide range of DOD agencies to study human performance during environmental stress. </span></em></p>Working a day on the firelines as a wildland firefighter can require the endurance of riding the Tour de France. That takes a toll, as a physiologist explains.Brent C. Ruby, Professor of exercise and work physiology, University of MontanaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2137192023-09-22T12:30:44Z2023-09-22T12:30:44ZAaron Rodgers’ season-ending Achilles tear resurfaces questions about player safety on artificial turf<figure><img src="https://images.theconversation.com/files/549613/original/file-20230921-23-1tbdis.jpg?ixlib=rb-1.1.0&rect=4%2C12%2C2780%2C1882&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">New York Jets quarterback Aaron Rodgers suffered a torn Achilles tendon after being sacked by Buffalo Bills defensive end Leonard Floyd.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/aaron-rodgers-of-the-new-york-jets-is-sacked-during-the-news-photo/1689810103?adppopup=true">Jim McIsaac/Getty Images</a></span></figcaption></figure><p>In the first quarter of his first game as a New York Jet, quarterback Aaron Rodgers dropped back to pass. Buffalo Bills defensive end Leonard Floyd blew past the offensive line and wrapped up Rodgers, dragging him awkwardly to the ground. Rodgers got up, before falling back to the turf, grimacing in pain. </p>
<p>Just like that, the Jets lost their biggest offseason acquisition <a href="https://www.usatoday.com/story/graphics/2023/09/18/aaron-rodgers-complete-achilles-tear-explained/70853550007/">to a season-ending Achilles tendon tear</a>.</p>
<p>Blame quickly circulated. To some football players, it wasn’t Rodgers’ age – the quarterback will turn 40 in December 2023 – nor was it simple bad luck that caused the injury.</p>
<p><a href="https://www.cnn.com/2023/09/13/sport/aaron-rodgers-injury-artificial-turf-nfl-spt-intl/index.html">It was the artificial turf</a> at MetLife Stadium, where the Jets and New York Giants play their home games.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1701402938642415783"}"></div></p>
<p>Two days after the injury, the NFL Players Association <a href="https://www.orlandosentinel.com/2023/09/13/nfl-players-union-renews-call-for-grass-fields-after-aaron-rodgers-injury/">called on the league to convert all playing fields to natural grass</a>. It joined <a href="https://www.si.com/nfl/2014/05/21/nfl-history-95-objects-artificial-turf">a chorus of players and coaches</a> across sports who, for decades, have blamed artificial turf for injuries ranging from sprains and strains to tendon ruptures.</p>
<p><a href="https://scholar.google.com/citations?user=_AxjgecAAAAJ&hl=en">As a physical therapist, researcher</a> and director of performance and sports science, I help elite athletes minimize injury risk and maximize performance. It’s always difficult to tell whether an injury could have been prevented had someone not been playing on a certain surface - particularly because muscle and tendon strength, pliability and stiffness usually play a much more important role.</p>
<p>However, some studies have linked playing on artificial turf to injury risk, though the risk tends to be limited to a few body parts.</p>
<h2>The grass is always greener?</h2>
<p>In 1966, Houston’s Astrodome became the first major sports venue <a href="https://doi.org/10.1177%2F1941738118793378">to install synthetic turf</a>. It was originally called “<a href="https://www.thoughtco.com/history-of-astroturf-1991235">ChemGrass</a>,” though Monsanto, the company that invented it, later rebranded its product as “AstroTurf” due to its association with the Astrodome.</p>
<p>Not everyone was jazzed about the cutting-edge carpet.</p>
<p>“Imagine that – a [US]$45 million ballpark and a 10-cent infield,” <a href="https://sciencehistory.org/stories/magazine/turf-wars/">groused Chicago Cubs manager Leo Durocher</a>. Players said the surface didn’t have the same give as grass – making <a href="https://www.nytimes.com/1975/10/14/archives/astro-turf-is-looming-as-reds-weapon-astro-turf-looming-as-red.html">diving for balls a risky endeavor</a> – and <a href="https://www.latimes.com/archives/la-xpm-1989-10-17-sp-269-story.html">claimed their knees deteriorated</a> from the daily grind of playing on the harder surface. </p>
<p>The technology has come a long way since then. Today’s synthetic turf systems have shock-absorbing technology and glasslike fibers that essentially mimic natural grass. <a href="https://keystonesportsconstruction.com/10-ways-synthetic-turf-fields-beat-the-competition-grass-fields/">Its proponents argue</a> that they’re low-maintenance, cost effective and more durable. </p>
<p>Some athletes disagree. Not only do they point out that artificial turf is still a lot different to play on than grass, but they also question the league’s commitment to <a href="https://www.foxnews.com/sports/nfl-players-rip-league-artificial-turf-aaron-rodgers-season-ending-injury-profit-over-people">safety over saving money</a>.</p>
<figure class="align-center ">
<img alt="Panoramic view of domed baseball stadium with bright green artificial grass." src="https://images.theconversation.com/files/549624/original/file-20230921-22-kgyc7o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549624/original/file-20230921-22-kgyc7o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549624/original/file-20230921-22-kgyc7o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549624/original/file-20230921-22-kgyc7o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549624/original/file-20230921-22-kgyc7o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549624/original/file-20230921-22-kgyc7o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549624/original/file-20230921-22-kgyc7o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">When Houston’s Astrodome was built, it was dubbed the ‘Eighth Wonder of the World.’</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/general-view-of-the-astrodome-during-a-houston-astros-game-news-photo/50830647?adppopup=true">Bill Baptist/MLB via Getty Images</a></span>
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</figure>
<p>So what does the evidence show?</p>
<p><a href="https://doi.org/10.1177/0363546519833925">There have been studies</a> looking at the rate of injury on different playing surfaces. A handful have found that the overall incidence of football injuries is significantly higher on artificial playing surfaces. </p>
<p>However, orthopedic resident Heath Gould – a former college football player – <a href="https://doi.org/10.1177%2F2473011421S00217">led a review of existing studies</a> and found that most studies identified similar rates of injury on natural grass compared with artificial turf. There have even been <a href="https://pubmed.ncbi.nlm.nih.gov/20075177/">a few studies</a> that reported a higher overall injury rate on natural grass. </p>
<p>Interestingly, the incidence seemed to be related to specific body parts. There was a higher rate of foot and ankle injuries on artificial turf – both older versions and newer ones – compared with natural grass. <a href="https://doi.org/10.1016/j.eclinm.2023.101956">And a recent meta-analysis</a> observed that the overall incidence of injuries in professional soccer is actually lower on artificial turf than on grass. It concludes that the risk of injury can’t be used as an argument against artificial turf when considering the optimal playing surface for soccer. </p>
<p>These findings suggest that while playing surface is important to take into account when assessing injury risk, other factors must be considered.</p>
<h2>The human factor</h2>
<p>The human body is a kinetic chain that consists of body segments linked together by joints. Those joints need to work together to create and dissipate forces needed for us to move and perform athletic motions. </p>
<p>Any chain, however, is only as strong as its weakest link. The muscles, ligaments and tendons in our bodies play an important role in supporting those links. </p>
<p>For athletes, the stakes are even higher because of the incredible power and momentum they are able to generate and absorb. <a href="https://theconversation.com/stiff-muscles-are-a-counterintuitive-superpower-of-nba-athletes-116252">They rely on muscle, tendon and ligament stiffness</a> in order to take advantage of the elastic energy they create. Like a spring or rubber band, when a muscle is stretched, its stiffness helps create elastic energy that can then be used with a muscle contraction to help athletes run, jump, accelerate or decelerate. </p>
<p><a href="https://www.doi.org/10.2519/jospt.2018.7192">Research I conducted with colleagues</a> found that injuries can occur when there is too much stiffness or compliance in these tissues. In fact, we’ve found that <a href="https://doi.org/10.1123/jab.2022-0088">Achilles tendon ruptures</a> in professional basketball players tend to occur when the ankle flexes beyond the muscle and tendon’s ability to withstand the forces incurred with certain maneuvers.</p>
<p>Certainly, several other variables factor into injuries: muscular strength, power, flexibility, body type and tissue elasticity.</p>
<h2>What gives?</h2>
<p>Playing surface is another important aspect of this equation. </p>
<p>Think about the contact point between the athlete and the surface that they’re playing on. This represents an additional link in the chain because forces must be exchanged between the player and the ground.</p>
<p><a href="https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/newtons-laws-of-motion/">As Isaac Newton noted</a>, “For every action there is an equal and opposite reaction.” </p>
<p>The playing surface must be firm enough to allow an athlete to push off to accelerate or jump. At the same time, the surface must be compliant enough to be able to absorb forces when a player lands or slows down. There is a sweet spot between the ability for playing surfaces to offer enough resistance and support, but also absorb forces. </p>
<p>Therein lies the question as to whether artificial turf is appropriate and safe enough for athletes. The research might be somewhat hazy, but Rodgers’ Achilles tendon rupture did occur in a part of the body <a href="https://pubmed.ncbi.nlm.nih.gov/35593739/">that is correlated with more injuries on artificial turf</a>. </p>
<p>It’s encouraging that playing surface technology continues to evolve. But replicating mother nature isn’t easy.</p><img src="https://counter.theconversation.com/content/213719/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philip Anloague does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Two days after Rodgers’ injury, the NFL players union called on the league to convert all playing fields to natural grass.Philip Anloague, Adjunct Professor of Physical Therapy, University of DaytonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2108082023-09-13T20:05:28Z2023-09-13T20:05:28ZDoes running water really trigger the urge to pee? Experts explain the brain-bladder connection<figure><img src="https://images.theconversation.com/files/547929/original/file-20230913-19-o53nya.jpg?ixlib=rb-1.1.0&rect=103%2C103%2C5647%2C3733&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>We all know that feeling when nature calls – but what’s far less understood is the psychology behind it. Why, for example, do we get the urge to pee just before getting into the shower, or when we’re swimming? What brings on those “nervous wees” right before a date?</p>
<p>Research suggests our brain and bladder are in constant communication with each other via a neural network called the <a href="https://www.einj.org/journal/view.php?doi=10.5213/inj.2346036.018">brain-bladder axis</a>. </p>
<p>This complex web of circuitry is comprised of sensory neural activity, including the sympathetic and parasympathetic nervous systems. These neural connections allow information to be sent <a href="https://doi.org/10.3390/diagnostics12123119">back and forth</a> between the brain and bladder. </p>
<p>The brain-bladder axis not only facilitates the act of peeing, but is also responsible for telling us we need to go in the first place. </p>
<h2>How do we know when we need to go?</h2>
<p>As the bladder fills with urine and expands, this activates special receptors detecting stretch in the nerve-rich lining of the bladder wall. This information is then relayed to the “periaqueductal gray” – a part of the brain in the brainstem which <a href="https://www.nature.com/articles/nrn2401">constantly monitors</a> the bladder’s filling status. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=570&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=570&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547931/original/file-20230913-19-2kgkhk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=570&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The periaqueductal gray is a section of gray matter located in the midbrain section of the brainstem.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Brainstem#/media/File:1311_Brain_Stem.jpg">Wikimedia/OpenStax</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Once the bladder reaches a certain threshold (roughly 250-300ml of urine), another part of the brain called the “pontine micturition centre” is activated and signals that the bladder needs to be emptied. We, in turn, <a href="https://pubmed.ncbi.nlm.nih.gov/16254993/">register this</a> as that all-too-familiar feeling of fullness and pressure down below.</p>
<p>Beyond this, however, a range of situations can trigger or exacerbate our need to pee, by increasing the production of urine and/or stimulating reflexes in the bladder.</p>
<h2>Peeing in the shower</h2>
<p>If you’ve ever felt the need to pee while in the shower (no judgement here) it may be due to the sight and sound of running water. </p>
<p>In a 2015 study, <a href="https://doi.org/10.1371/journal.pone.0126798">researchers demonstrated</a> that males with urinary difficulties found it easier to initiate peeing when listening to the sound of running water being played on a smartphone. </p>
<p>Symptoms of overactive bladder, including urgency (a sudden need to pee), have also been <a href="https://www.alliedacademies.org/articles/environmental-cues-to-urgency-and-incontinence-episodes-in-chinesepatients-with-overactive-urinary-bladder-syndrome.html">linked to</a> a range of environmental cues involving running water, including washing your hands and taking a shower.</p>
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Read more:
<a href="https://theconversation.com/does-it-matter-if-you-sit-or-stand-to-pee-and-what-about-peeing-in-the-shower-206869">Does it matter if you sit or stand to pee? And what about peeing in the shower?</a>
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<p>This is likely due to both physiology and psychology. Firstly, the sound of running water may have a relaxing <em>physiological</em> effect, increasing activity of the parasympathetic nervous system. This would relax the bladder muscles and prepare the bladder for emptying.</p>
<p>At the same time, the sound of running water may also have a conditioned <em>psychological</em> effect. Due to the countless times in our lives where this sound has coincided with the actual act of peeing, it may trigger an instinctive reaction in us to urinate. </p>
<p>This would happen in the same way <a href="https://www.simplypsychology.org/pavlov.html">Pavlov’s dog learnt</a>, through repeated pairing, to salivate when a bell was rung.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547933/original/file-20230913-21-yn86yb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Over our lifetimes we may become conditioned to associate peeing with running water, due to the concurrence of these events.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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</figure>
<h2>Cheeky wee in the sea</h2>
<p>But it’s not just the sight or sound of running water that makes us want to pee. Immersion in cold water has been shown to cause a “cold shock response”, <a href="https://pubmed.ncbi.nlm.nih.gov/19945970">which activates</a> the sympathetic nervous system. </p>
<p>This so-called “fight or flight” response drives up our blood pressure which, in turn, causes our kidneys to filter out more fluid from the bloodstream to stabilise our blood pressure, in a process called “<a href="https://link.springer.com/article/10.1007/BF00864230">immersion diuresis</a>”. When this happens, our bladder fills up faster than normal, triggering the urge to pee. </p>
<p>Interestingly, immersion in very warm water (such as a relaxing bath) may also increase urine production. In this case, however, it’s due to activation of the parasympathetic nervous system. <a href="https://doi.org/10.1007/s004210050065">One study</a> demonstrated an increase in water temperature from 40°C to 50°C reduced the time it took for participants to start urinating. </p>
<p>Similar to the effect of hearing running water, the authors of the study suggest being in warm water is calming for the body and activates the parasympathetic nervous system. This activation can result in the relaxation of the bladder and possibly the pelvic floor muscles, bringing on the urge to pee.</p>
<h2>The nervous wee</h2>
<p>We know stress and anxiety can cause bouts of nausea and butterflies in the tummy, but what about the bladder? Why do we feel a sudden and frequent urge to urinate at times of heightened stress, such as before a date or job interview?</p>
<p>When a person becomes stressed or anxious, the body goes into fight-or-flight mode through the activation of the sympathetic nervous system. This triggers a cascade of physiological changes designed to prepare the body to face a perceived threat.</p>
<p>As part of this response, the muscles surrounding the bladder may contract, leading to a more urgent and frequent need to pee. Also, as is the case during immersion diuresis, the increase in blood pressure associated with the stress response may <a href="https://doi.org/10.1172/JCI102496">stimulate</a> the kidneys to produce more urine.</p>
<h2>Some final thoughts</h2>
<p>We all pee (most of us several times a day). Yet <a href="https://doi.org/10.5489/cuaj.1150">research has shown</a> about 75% of adults know little about how this process actually works – and even less about the brain-bladdder axis and its role in urination. </p>
<p><a href="https://www.continence.org.au/about-us/our-work/key-statistics-incontinence#:%7E:text=Urinary%20incontinence%20affects%20up%20to,38%25%20of%20Australian%20women1.">Most Australians</a> will experience urinary difficulties at some point in their lives, so if you ever have concerns about your urinary health, it’s extremely important to consult a healthcare professional. </p>
<p>And should you ever find yourself unable to pee, perhaps the sight or sound of running water, a relaxing bath or a nice swim will help with getting that stream to flow.</p>
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Read more:
<a href="https://theconversation.com/is-urine-sterile-do-urine-therapies-work-experts-debunk-common-pee-myths-191862">Is urine sterile? Do urine 'therapies' work? Experts debunk common pee myths</a>
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<img src="https://counter.theconversation.com/content/210808/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Helen O'Connell is the current president of The Urological Society of Australia and New Zealand (USANZ).</span></em></p><p class="fine-print"><em><span>David Homewood, James Overs, and Simon Robert Knowles do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A shower, a swim, a warm bath: there are a number of common pee triggers. So how much of our need to pee comes down to psychology?James Overs, Research Assistant, Swinburne University of TechnologyDavid Homewood, Urology Research Registrar, Western Health, Melbourne HealthHelen Elizabeth O'Connell AO, Professor, University of Melbourne, Department of Surgery. President Urological Society Australia and New Zealand, The University of MelbourneSimon Robert Knowles, Associate Professor and Clinical Psychologist, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2010792023-08-08T12:28:10Z2023-08-08T12:28:10ZYellow jerseys of the fireline: A day fighting wildfires can require as much endurance as riding the Tour de France<figure><img src="https://images.theconversation.com/files/516189/original/file-20230319-26-kbr57v.jpg?ixlib=rb-1.1.0&rect=0%2C3%2C2047%2C1333&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ruby Mountain hotshots construct a fire line during the Dixie Fire in 2021.
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/51434898834">Joe Bradshaw/BLM</a></span></figcaption></figure><p>For three weeks in July, the world’s most elite bike racers climb steep mountains and sprint along historic cobblestones to capture the coveted <a href="https://en.wikipedia.org/wiki/General_classification_in_the_Tour_de_France">yellow jersey</a> or the race leader in the Tour de France. It’s a 22-day feat of human endurance that requires constant eating and drinking to manage the <a href="https://doi.org/10.1055/s-2007-1024951">average daily energy demand</a> of about 6,000 calories, equivalent to around 12 <a href="https://www.mcdonalds.com/us/en-us/meal/hamburger-happy-meal.html">McDonald’s Happy Meals</a>, and just over 1.5 gallons of water.</p>
<p>Nearly 5,000 miles away in the mountains of North America, radios crackle with chatter from a wildfire incident command post, air operations and other crews fighting a wildfire. Up the fireline, the swings of <a href="https://en.wikipedia.org/wiki/Pulaski_(tool)">Pulaskis</a>, axlike hand tools, are <a href="https://www.nps.gov/articles/wildland-fire-fireline-construction.htm">carving a fuel break</a> into the land. The weather forecast predicts a high of nearly 100 degrees Fahrenheit (38 C) with wind, a combination that can push the fire high up into the canopy of dense lodgepole pines on the mountainside.</p>
<p>The yellow jerseys here are sooty, sweat-stained and <a href="https://www.nwcg.gov/sites/default/files/committee/docs/fsppes-2022-modified-shirt-tech-tip.pdf">flame-resistant</a>, with a strong, earthy odor.</p>
<p>Hotshot crews like this one are the elite workforce of the forest, and the demand on their bodies can rival that of the cyclists in the Tour de France, as <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/cphy.c220016">my team’s research</a> shows.</p>
<p>On this morning, the Hotshot crew has already hiked 3 miles up steep, uneven terrain and built nearly 1,200 feet of fire line. It is not yet 10 a.m. The day is just beginning, the first day of a 14-day rollout.</p>
<h2>Measuring the physical strain</h2>
<p>The dew hangs heavy on the inside of the small tent as the 4:30 a.m. alarm disrupts my intermittent sleep. The sounds of sleeping bag and tent zippers signals the beginning of a new day in a remote Montana fire camp.</p>
<p>Using a headlamp, I arrange the sample collection tubes in a plastic rack and wait for a few members of the <a href="https://www.lolohotshots.com/">Lolo Hotshots</a> to wander through my field laboratory to drop off an early morning urine sample. </p>
<p>The crew is participating in a study that my team from Montana is conducting to measure the physical strain and total energy demands of work on an active wildfire, with the goal of finding ways to improve firefighter fueling strategies and ultimately health and safety on the line.</p>
<figure class="align-center ">
<img alt="A firefighter in the woods loaded with gear, including chain saw, fuel canister and full backpack." src="https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517270/original/file-20230323-1736-9e0l7h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A Lakeview Hotshots firefighter carries equipment and fuel for containing the Cedar Creek fire near Oakridge, Ore., in 2022.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/hotshot-firefighter-works-to-contain-the-cedar-creek-fire-news-photo/1243179718">Dan Morrison / AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>Crew members are outfitted with a <a href="https://equivital.com/mobile-physiological-monitoring">series of lightweight monitors</a> that measure heart rate, as well as movement patterns and speed using GPS. Each swallows a temperature-tracking sensor before breakfast that will transmit measures of core body temperature each minute throughout the work shift. </p>
<p>Just before 6 a.m., the crew heads west in their <a href="https://www.bmefire.com/apparatus/crew-carrier/">crew carrier rigs</a> into the adjacent wilderness. They have lines to dig and a fire to contain.</p>
<h2>Burning 6-14 calories per minute</h2>
<p>On the fire line, pack straps dig into the neck and shoulders with each swing of the Pulaski. It’s a constant reminder that everything wildland firefighters need, they carry, all day.</p>
<p>The critical water and food items, supplies, extra gear, and fire line tools – Pulaskis, chain saws, and fuel – add up to an average gear weight often exceeding 50 pounds.</p>
<p><a href="https://doi.org/10.1016/j.wem.2018.03.006">Hiking with a load</a> and <a href="https://doi.org/10.1071/WF9970069">digging firelines</a> with hand tools burns about 6 to 14 calories per minute. Heart rates rise in response to an increased pace of digging. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dozen firefighters, some leaning on their Pulaski tools, look at a map of the fire. They're standing in a wooded area with tall pines behind them." src="https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516191/original/file-20230319-26-8hpr9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Firefighters are often working in rough forest terrain involving long hikes and steep slopes. Here, the Ruby Mountain Hotshot Crew gets a briefing on the Dixie Fire in California in 2021.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/51434899564">Joe Bradshaw/BLM</a></span>
</figcaption>
</figure>
<p>Measured with the same techniques used to quantify the <a href="http://doi.org/10.1055/s-2007-1024951">energy demands of Tour de France riders</a>, wildland firefighters demonstrate an average total energy expenditure approaching <a href="https://pubmed.ncbi.nlm.nih.gov/12048336/">4,000 to 5,000 calories per day</a>. Some days can <a href="https://doi.org/10.1016/j.wem.2014.12.010">exceed the Tour’s average of about 6,000 calories</a>. Add to that a daily water need of <a href="https://doi.org/10.1249/01.MSS.0000089348.39312.4D">1.5</a> to over <a href="https://doi.org/10.1016/j.wem.2014.12.010">2 gallons</a>. </p>
<p>This isn’t just for a few days. Fire season in the western United States can last five months or more, with most Hotshot crews accumulating four to five times the number of operational days of the 22-day Tour de France and over 1,000 hours of overtime.</p>
<figure class="align-center ">
<img alt="Silhouettes of five firefighters, one with a headlamp lighting the way, walking through a wooded field with fire burning in the background." src="https://images.theconversation.com/files/516190/original/file-20230319-8066-paqnw4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516190/original/file-20230319-8066-paqnw4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516190/original/file-20230319-8066-paqnw4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516190/original/file-20230319-8066-paqnw4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516190/original/file-20230319-8066-paqnw4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516190/original/file-20230319-8066-paqnw4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516190/original/file-20230319-8066-paqnw4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A Wyoming Hotshots crew conducts night operations on the Pine Gulch fire in Colorado in August 2020.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/50321123752">Kyle Miller, Wyoming Hotshots, USFS</a></span>
</figcaption>
</figure>
<p>Every year, on average, about <a href="https://sgp.fas.org/crs/misc/IF10244.pdf">60,000 wildfires will burn</a> across roughly 70 million acres in the western U.S. Drying grasses and forests create fuel for the spark of a lightning strike, power line or carelessly abandoned campfire, and windy summer weather can spread that into a blaze. When those fires could threaten communities, the Hotshots are mobilized.</p>
<h2>Impact on the wildland firefighter’s body</h2>
<p>As the work shift progresses, the Hotshots constantly monitor their surroundings and <a href="https://pubmed.ncbi.nlm.nih.gov/17545892/">self-regulate</a> <a href="https://doi.org/10.1016/j.wem.2020.01.009">nutrient</a> and <a href="https://doi.org/10.1580/07-WEME-OR-114.1">fluid intake</a>, knowing their shift will last 12 to 16 hours.</p>
<p>During intense activity in high heat, their <a href="https://doi.org/10.1580/07-WEME-OR-114.1">fluid intake</a> can increase to 32 ounces per hour or more.</p>
<p>The highest-intensity activity is generally during the <a href="https://doi.org/10.1016/j.wem.2018.03.006">early morning hike to the fire line</a>. However, the metabolic demands can sharply increase if crews are forced into a rapid <a href="https://www.publish.csiro.au/wf/WF02025">emergency evacuation from the fire</a>, as more than <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/cphy.c220016">25 years of wildland firefighter physiology research</a> shows.</p>
<p>The most effective way for wildland firefighters to stay fueled is to eat small meals frequently throughout the work shift, similar to the patterns perfected by riders in the Tour. This <a href="https://doi.org/10.1093/ajcn/76.1.120">preserves cognitive health</a>, helping firefighters stay focused and sharp for making potentially lifesaving decisions and keenly aware of their ever-dynamic surroundings, and boosts <a href="https://doi.org/10.1249/mss.0b013e318040b2fb">work performance</a>. It also helps slow the depletion of <a href="https://doi.org/10.1016/j.wem.2010.09.019">important muscle fuel</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Lists of details about wildland firefighter loads like weight, energy demand, water budget, and heart rate." src="https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=566&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=566&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=566&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=712&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=712&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518540/original/file-20230330-2194-t2x9hy.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=712&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Resource demands on a wildland firefighter.</span>
<span class="attribution"><span class="source">Christopher Durdle, Brent Ruby</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Despite the physical and emotional stress of being in an active fire, the firefighters’ <a href="https://doi.org/10.1016/j.wem.2014.12.010">heart rates rarely exceed 160 beats per minute</a>, about 70% to 80% of maximal heart rate and an intensity common during a higher-intensity training run. Their heart rates are mostly maintained between 100 and 140 beats per minute, typical of a brisk walk or hike, but they maintain that for hours.</p>
<p>Although crews gradually <a href="https://doi.org/10.1016/j.jtherbio.2014.08.009">acclimatize to the heat</a> over the season, the risk for <a href="https://doi.org/10.1016/j.wem.2011.01.008">heat exhaustion</a> is ever present if the work rate is not kept in check. This cannot be prevented by simply drinking more water during long work shifts. However, regular breaks and having a strong aerobic capacity provides some protection by <a href="https://doi.org/10.7205/MILMED-D-12-00524">reducing heat stress</a> and overall risk.</p>
<h2>The season takes a toll</h2>
<p>Hotshots are physically fit, and they train for the fire season just as many athletes train for their competition season. Most crew members are hired temporarily during the fire season – typically from <a href="https://www.epa.gov/climate-indicators/climate-change-indicators-wildfires">May to October, but expanding as the planet warms</a>. And there are <a href="https://www.fs.usda.gov/managing-land/fire/safety/wct">distinct fitness requirements for the job</a>.</p>
<p>Still, with the immense physical demands of the job, crew members often experience a <a href="https://doi.org/10.1097/JOM.0000000000001535">decay in metabolic and cardiovascular health</a> and an <a href="https://doi.org/10.1097/JOM.0000000000002446">increase in cholesterol, blood lipids and body fat</a>. It is unclear why such a hardworking job often makes firefighters less healthy, requiring an off-season reset to recover, retrain and rebuild.</p>
<figure class="align-center ">
<img alt="A man wearing a head lamp leans over a set of vials with an eyedropper, while a firefighter in a yellow jacket sits nearby." src="https://images.theconversation.com/files/516412/original/file-20230320-24-f9imbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516412/original/file-20230320-24-f9imbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516412/original/file-20230320-24-f9imbc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516412/original/file-20230320-24-f9imbc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516412/original/file-20230320-24-f9imbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516412/original/file-20230320-24-f9imbc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516412/original/file-20230320-24-f9imbc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Getting samples before firefighters head out to the fire lines, as the author, Brent Ruby, is doing here, often means working in the dark.</span>
<span class="attribution"><span class="source">Courtesy of Brent Ruby</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The season causes damage. This unfolds counter to the commonly accepted benefits of <a href="https://pubmed.ncbi.nlm.nih.gov/25905196/">regular exercise</a>. <a href="https://doi.org/10.1080/08958370600985875">Pollutant and smoke exposure</a>, lapses in <a href="https://doi.org/10.1249/MSS.0b013e31817f4d58">nutrition</a>, <a href="https://doi.org/10.1097/JOM.0000000000001175">sleep disorders</a> and <a href="https://doi.org/10.1080/08039488.2017.1368703">chronic stress</a> during the season seems to gradually poke holes in the Hotshot armor.</p>
<p>Progressive intervention strategies can help, such as educational programs to inform specific physical training and nutritional needs, mindfulness training to reduce the risk of job-oriented anxiety and depression and emotional support for individual crew members and families.</p>
<p>Developing off-season practices that pay close attention to both physical and mental health recovery can help limit harm to firefighters’ health. Many Hotshots bounce back and <a href="https://www.govexec.com/workforce/2023/01/federal-firefighter-groups-find-flaws-watchdogs-conclusions-recruitment-retention-challenges/382428/">return season after season</a>.</p>
<h2>Back in camp</h2>
<p>A 14-hour intervention with the land is physically and emotionally exhausting.</p>
<figure class="align-center ">
<img alt="Three firefighters lounge on air mattresses while reading. Tents are behind them, and boots are in the foreground." src="https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517271/original/file-20230323-2606-r5besf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">‘Home’ on the firelines is typically groups of tents and air mattresses.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/WesternWildfires/0dff6baed4fb4394a72b99895035a1db/photo">AP Photo/Ted S. Warren</a></span>
</figcaption>
</figure>
<p>Back in camp, the crew provides another urine sample, and I download their monitors’ data. Their fireline stories have all the elements of American folklore and Western novels, and they bounce between excitement about the events of the day and wondering what the data from their sensors and tests might show. I will use that data combined with our previous research to help crews develop early-season training and advanced nutrition strategies. </p>
<p>A large, warm meal starts to reload precious muscle fuel. In a few hours, a new shift will begin for the Hotshots, and another day in the yellow jersey.</p><img src="https://counter.theconversation.com/content/201079/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brent C. Ruby currently receives funding from the Air Force Research Labs and The US Army Medical and Materiel Command. The research in wildland fire has been funded by the US Forest Service, the US Army, the US Air Force, the Office of Naval Research, and the Gatorade Sports Science Institute</span></em></p>Twenty-five years of research show what it takes to fuel wildland firefighters through an average day, and the toll the long seasonal work takes on their bodies.Brent C. Ruby, Research Professor, School of Integrative Physiology and Athletic Training, University of MontanaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1990822023-05-02T21:44:36Z2023-05-02T21:44:36ZDoes our gut microbiota really influence our health and life expectancy?<figure><img src="https://images.theconversation.com/files/507937/original/file-20230202-11974-o90i7b.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C991%2C561&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Certain factors can disrupt the gut microbiota. These include our diet, alcohol consumption, antibiotics and inflammatory bowel disease.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>The intestinal microbiota is the set of bacteria and viruses that live inside your gut. Microbiota perform a variety of functions, including digesting food and protecting against specific pathogens. </p>
<p>There are several things that can <a href="https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/fecal-transplant">disrupt the gut microbiota</a>, including diet, alcohol consumption, antibiotics and inflammatory bowel disease. These cause imbalances, known as “dysbiosis” which, in turn, are associated with a <a href="https://doi.org/10.1128/mBio.01492-17">wide array of chronic diseases</a>. </p>
<p>In the last decade, the results of hundreds of studies in animal models have suggested that gut dysbiosis may play a role in several metabolic disturbances. Furthermore, in rodents, the implantation of certain bacteria <a href="https://doi.org/10.1038/nm.4236">could influence weight and metabolic profile</a>. What’s more, transferring the gut microbiota from a thin mouse to a heavy mouse allows it to lose weight. Is this too good to be true?</p>
<p>Respectively a student and a full professor in the Department of Medicine at Université Laval, our goal is to identify new therapeutic targets for chronic diseases and healthy life expectancy by using an approach based on genetic epidemiology. This short article aims to summarize and contextualize our recent research work <a href="https://doi.org/10.1186/s12967-022-03799-5">on the gut microbiota</a>.</p>
<h2>The importance of a causal link</h2>
<p>Scientists have suggested that eating certain foods such as dietary fibre, antioxidant-rich fruits and red meat may have an effect <a href="https://doi.org/10.1056/NEJMoa1109400">on the gut microbiota</a>. Some even suggest that microbiota could become a therapeutic target for the prevention or treatment of certain chronic diseases. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="conceptual illustration of the gut microbiome" src="https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507397/original/file-20230131-16-arvjen.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The gut microbiota is the set of bacteria and viruses in our gut. It is involved in various functions, such as the digestion of food and protection against certain pathogens.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>For the microbiota to become a therapeutic target of interest, it is essential to establish a causal link between the characteristics of the gut microbiota and chronic diseases. A causal link suggests that modifying the microbiota <a href="https://doi.org/10.1016/j.cell.2019.12.025">would decrease the risk of developing a disease</a>. However, while several observational (non-experimental) studies in humans have identified statistical associations between <a href="https://doi.org/10.1016/j.febslet.2014.09.039">various markers of gut microbiota and chronic disease</a>, causality has not been clearly established. </p>
<p>For example, it is not known whether gut dysbiosis is the cause or consequence of disease (reverse causation). It is also not known whether both are influenced by other “confounding” factors that are associated with both gut microbiota and chronic disease. One could think, for example, of the quality of <a href="https://doi.org/10.1038/s41586-020-2881-9">our diet, our weight or our alcohol consumption</a>. </p>
<p>So, the aim of our work was to determine whether there is a direct and causal relationship between gut microbiota and metabolic markers such as weight, eight chronic diseases and human longevity using a genetic approach called Mendelian randomization.</p>
<h2>The power of genetic data</h2>
<p>Mendelian randomization attempts to establish causal links from genetic data. To do this, Mendelian randomization uses genetic variants (frequent changes in our genome sequence called nucleotide polymorphisms) that are strongly associated with a risk factor (gut microbiota), to establish a causal link with a dependent variable (health markers and diseases), <a href="https://theconversation.com/voici-comment-les-lois-de-la-genetique-nous-aident-a-prevenir-les-maladies-chroniques-144153">as described in a recent article</a>. Since the variations in our genome are established at the time of embryo formation and remain stable throughout our lives, this natural randomization experiment is not subject to reverse causality bias, since the presence of disease does not influence our genetic code. It is also not subject to the effect of confounding factors, since the genetic variations used are specifically associated with the characteristics of the gut microbiota. </p>
<p>We included genetic data from tens of thousands of individuals from several cohorts. We identified genetic variants associated with 10 fecal and blood metabolites. The metabolites included are small molecules produced by the gut microbiota that have previously been associated with gut dysbiosis and certain diseases. We also identified genetic variants of dozens of microbial taxa (e.g. a species, genus or family of bacteria). We studied nine cardiometabolic traits (weight, blood pressure, blood lipids, insulin, etc.) as well as eight chronic diseases: Alzheimer’s disease, depression, Type 2 diabetes, fatty liver disease, atherosclerotic coronary artery disease, stroke, osteoporosis and renal failure. We also studied the effect of these factors associated with gut microbiota on healthy life expectancy and longevity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="figure representing several molecules" src="https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=642&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=642&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=642&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=807&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=807&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507393/original/file-20230131-12649-n9up99.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=807&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Small organic molecules called metabolites are produced by gut bacteria. These molecules could reach organs such as the liver and the brain. However, their role in the development of chronic diseases and life expectancy is controversial.</span>
<span class="attribution"><span class="source">(Benoît Arsenault)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>We hypothesised that, in the light of previously published data, a causal link would be revealed between gut dysbiosis and chronic diseases associated with aging.</p>
<p>However, contrary to our hypothesis, this Mendelian randomization analysis did not show significant effects of gut microbiota on metabolic factors and chronic diseases. Seven associations between certain microbial parameters and chronic diseases associated with aging appear to be potentially causal, but their effect is small and we cannot rule out the possibility that these associations happened by chance. Overall, the results offer little support for the hypothesis that the gut microbiota has a significant effect on our weight, metabolism and risk of developing chronic diseases.</p>
<h2>Results that call for caution</h2>
<p>These results suggest that the previously observed associations may not be causal. The associations could be explained by the diseases themselves (reverse causality bias) or by confounding factors (confounding bias) such as diet, medication, smoking, metabolic health, or others. However, these findings are consistent with the results of four recent randomized clinical trials showing that transferring gut microbiota from thin to heavyweight individuals does not lead to <a href="https://doi.org/10.3390/nu11102291">any weight loss or significant improvement in metabolic profile</a>.</p>
<p>Mendelian randomization is a method that has several advantages over observational studies. However, these results need to be contextualized. It is entirely possible that the genetic parameters we used to predict the metabolites and microbial species associated with gut dysbiosis do not fully capture the complexity of the gut microbiota. This would diminish our ability to identify meaningful associations. Therefore, studies with larger sample sizes and better characterization of the gut microbiota and its metabolites will be needed to determine whether certain gut bacteria play a key role in the etiology (the study of causes) of chronic disease and longevity.</p>
<p>Although the impact of gut dysbiosis on chronic disease appears to be limited, gut health is important for other aspects of human health. For example, the microbiota prevents other harmful bacteria from colonizing our gut. In addition, it allows us to digest certain nutrients (e.g. dietary fibre) that would otherwise <a href="https://doi.org/10.1136/bmj.k2179">be rejected by our bodies</a>. </p>
<p>Therapies that modulate the gut microbiota have recently been approved by U.S. health authorities for the prevention of <em>C. difficile</em> infections (a bacterium that causes diarrhea and other serious intestinal diseases). Our results, along with results from clinical studies less prone to reverse causality and confounding bias, do not, however, support a significant effect of gut dysbiosis on chronic disease. </p>
<p>These results support the conclusion that the potential of the microbiota as a therapeutic target for chronic diseases is, at present, low. We urge health professionals and the general public to be cautious about diagnostic tests based on gut microbiota to diagnose health problems that are not validated by the relevant health authorities. </p>
<p>Most importantly, we urge health professionals to avoid recommending specific interventions based on the mere fact that they would influence the parameters of the gut microbiota.</p><img src="https://counter.theconversation.com/content/199082/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Éloi Gagnon has received funding from the Fonds de recherche du Québec - Santé (FRQS).</span></em></p><p class="fine-print"><em><span>Benoit Arsenault has received research funding from the Canadian Institutes of Health Research, the Fonds de recherche du Québec - Santé, the Institut universitaire de cardiologie et de pneumologie de Québec Foundation, Pfizer and Silence Therapeutics.</span></em></p>A new study shows that the gut microbiota has little or no effect on our weight, metabolism and risk of developing chronic diseases.Éloi Gagnon, PhD Candidate, Université LavalBenoit Arsenault, Chercheur au Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec et Professeur titulaire au Département de médecine, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2035382023-04-21T12:40:48Z2023-04-21T12:40:48ZKeeping NBA players on the court is no small ‘feet’<figure><img src="https://images.theconversation.com/files/521420/original/file-20230417-16-xu2g2y.jpg?ixlib=rb-1.1.0&rect=546%2C7%2C3302%2C2186&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Boston Celtics center Robert Williams III falls to the court after suffering a toe injury during a playoff game in May 2021.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/robert-williams-iii-of-the-boston-celtics-reacts-after-news-photo/1318749877?adppopup=true">Maddie Malhotra/Getty Images</a></span></figcaption></figure><p>The NBA playoffs provide a stage for some of the biggest and tallest athletes in the world. With an <a href="https://www.hoopsaddict.com/average-nba-players-shoe-size/">average height of 6 feet, 7 inches and an average weight of 225 pounds</a>, players have a lot of skin, bone and muscle to support. </p>
<p>That’s why their feet play such an outsize role – literally and figuratively. </p>
<p>As a <a href="https://scholar.google.com/citations?view_op=list_works&hl=en&user=_AxjgecAAAAJ">physical therapist</a> and <a href="https://www.researchgate.net/profile/Philip-Anloague">researcher</a> who works closely with NBA athletes, I know just how difficult it is to maintain the health of players who are on the higher end of the foot-size spectrum.</p>
<p>And so while fans eagerly anticipate eye-popping dunks and crafty assists, I’ll be keeping an eye on the footwork of players like <a href="https://www.blazersedge.com/2023/3/9/23632448/kevin-durant-injury-news-phoenix-suns-ankle-warm-up-out">Kevin Durant</a>, <a href="https://www.inquirer.com/sixers/joel-embiid-injury-stats-sixers-20220502.html">Joel Embiid</a> and <a href="https://www.sportingnews.com/us/nba/news/lebron-james-foot-injury-timeline-return-latest-updates-lakers/vvvgzwzwzyy85emnklhjrtef">Lebron James</a>, each of whom has had challenges keeping their feet healthy.</p>
<h2>The importance of a strong foundation</h2>
<p>NBA players’ bodies take a beating. </p>
<p>They jump and come crashing down to the court up to 70 times per game, with centers – typically the tallest players on the court – <a href="https://doi.org/10.1123/jab.10.3.222">usually jumping the most</a>. </p>
<p>When players land, the impact on the ground can be as high as <a href="https://doi.org/10.1123/jab.10.3.222">four to six times</a> their body weight. The average player also changes direction <a href="https://theconversation.com/stiff-muscles-are-a-counterintuitive-superpower-of-nba-athletes-116252">every two to three seconds</a>, requiring stopping, turning and accelerating. Together, the jumps, twists, dekes and sprints put immense pressure on players’ foot, ankle and knee joints.</p>
<p>Like a tall building, basketball players need a solid foundation to support their massive bodies and withstand the power that is generated by all of this movement. </p>
<p>This is where the feet come in. The average shoe size of NBA players is close to a <a href="https://www.hoopsaddict.com/average-nba-players-shoe-size/">U.S. size 15</a>. NBA Hall-of-Famers Shaquille O'Neal and Bob Lanier famously wore <a href="https://www.hoopsaddict.com/average-nba-players-shoe-size/">size 22 shoes</a>. Among current players, Kevin Durant (18), Andre Drummond (19), Brook and Robin Lopez (20), Karl Anthony Towns (20) and Tacko Fall (22) lead the pack. The typical <a href="https://www.healthline.com/health/average-shoe-size-for-men#by-height">shoe size</a> for an American adult male is 10.5.</p>
<figure class="align-center ">
<img alt="Man poses with large shoe and championship ring." src="https://images.theconversation.com/files/521419/original/file-20230417-16-hkye8m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521419/original/file-20230417-16-hkye8m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=503&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521419/original/file-20230417-16-hkye8m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=503&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521419/original/file-20230417-16-hkye8m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=503&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521419/original/file-20230417-16-hkye8m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=633&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521419/original/file-20230417-16-hkye8m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=633&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521419/original/file-20230417-16-hkye8m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=633&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shaquille O'Neal’s massive feet are the stuff of legend.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/reebok-classic-and-shaquille-oneal-launch-the-new-shaq-news-photo/642706244?adppopup=true">Josh Brasted/Getty Images</a></span>
</figcaption>
</figure>
<p>Having big feet means having big bones that act as levers to create forces needed for athletic maneuvers. The foot’s 26 bones are intricately linked together with a series of 33 joints and bound together by <a href="https://doi.org/10.2519/jospt.2018.7192">soft tissues</a> like muscles, tendons and ligaments. The big toe, the arch of <a href="https://scholar.google.com/citations?view_op=view_citation&hl=en&user=_AxjgecAAAAJ&citation_for_view=_AxjgecAAAAJ:WF5omc3nYNoC">the midfoot</a> and the ankle are the gears that facilitate motion. </p>
<p>The soft tissue that connects these joints acts like a spring. Energy must be transferred from one joint to the other in a leverlike system that allows athletes to propel themselves forward when running and jumping. Likewise, these joints need to work together to absorb the shock of landing, slowing down or changing directions.</p>
<p>If this structure is not sound, the entire process can break down.</p>
<h2>What goes up must come down</h2>
<p>According to sports medicine specialist Mark C. Drakos, <a href="https://doi.org/10.1177/1941738109357303">62% of injuries</a> in the NBA occur below the waist, with foot and ankle injuries accounting for over 22% of them. Ankle injuries are the most common: A player has a <a href="https://doi.org/10.1177/0363546519864678">25.8% chance</a> of incurring one over the course of a season.</p>
<p><a href="https://doi.org/10.1177/1941738117738988">Stress fractures</a>, while less common, can be particularly debilitating, lingering for weeks or months. The most <a href="https://doi.org/10.1371/journal.pone.0201758">common bones</a> in the feet and lower leg to experience stress fractures are the navicular, talus, tibia and fibula. </p>
<p>Orthopedic surgeon <a href="https://surgery.mcmaster.ca/bio/dr.-moin-khan">Moin Kahn</a> conducted a case study and found that <a href="https://www.doi.org/10.1177/1941738109357303">only 30% of the athletes</a> who incurred a stress fracture from 2005 to 2015 were able to return to their previous level of play a year after their injury.</p>
<p>Having big feet doesn’t mean that an NBA athlete is destined to have an injury. But many big men have had their struggles. This list includes former players Bill Walton, Arvydas Sabonis, Yao Ming and Greg Oden, all of whom wore size 19 shoes. </p>
<p>Standing at 7 feet, 3 inches, NBA prospect Victor Wembanyama has already had his fair share of <a href="https://www.sbnation.com/nba/2022/8/3/23289223/victor-wembanyama-injury-history-muscle-psoas-back-nba-draft-2023">health issues</a>, including a fibular stress fracture. He wears a size 20.5 shoe.</p>
<h2>Getting off on the right foot</h2>
<p>Our research team has been studying joint range of motion, arch mobility, and foot and ankle mechanics in NBA players <a href="https://scholar.google.com/citations?view_op=list_works&hl=en&user=_AxjgecAAAAJ">to help athletes mitigate these injury risks</a>. </p>
<p>Part of that work involves building a database that includes the normal clinical measurements for elite basketball players – big toe extension, arch mobility, ankle flexion, hamstring flexibility and hip range of motion. </p>
<p>Understanding normal physical dimensions helps physical therapists and trainers to understand the risk of injury based on vulnerabilities in a player’s physical makeup. </p>
<p>For example, the average range of the big toe’s extension for the general population is 60 degrees. However, <a href="https://scholar.google.com/citations?view_op=list_works&hl=en&user=_AxjgecAAAAJ">our research</a> shows that the average NBA front court player has motion that is about 40 degrees. This means that the typical NBA player has feet and ankles that are stiffer than the average person’s. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/lYrA30qcvK4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Kevin Durant tears his Achilles tendon during Game 5 of the 2019 NBA Finals.</span></figcaption>
</figure>
<p>While this stiffness can be advantageous and work like a coiled spring that helps a basketball player run and jump, physical therapists must constantly work on these muscles to loosen them up. That’s because too much stiffness can cause <a href="https://journals.lww.com/nsca-scj/fulltext/2014/10000/lower_extremity_stiffness__effects_on_performance.12.aspx">bone injuries</a>.</p>
<p>Understanding what is happening during the heat of the action is also important. </p>
<p>We found that <a href="https://doi.org/10.1123/jab.2022-0088">Achilles tendon tears</a> tend to occur when the ankle bends more than 48 degrees. We suspect that this can happen when players’ ankles aren’t stiff enough: The tendon can’t adequately withstand the forces it encounters during game play.</p>
<p>The foot – a complex network of bones, joints and tissue – is ultimately only as strong as its weakest link. And the health of a team’s feet can end up being the one thing standing between them and a championship.</p><img src="https://counter.theconversation.com/content/203538/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philip Anloague does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The gargantuan feet of NBA players are the stuff of legend. But nearly two-thirds of their injuries occur below the waist, and they have a 25.8% chance of incurring an ankle injury every season.Philip Anloague, Associate Provost; Associate Professor of Physical Therapy, University of DaytonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1965572023-03-27T19:00:33Z2023-03-27T19:00:33ZWhat causes hiccups and how can you get rid of them?<figure><img src="https://images.theconversation.com/files/513100/original/file-20230302-24-dgnskj.jpg?ixlib=rb-1.1.0&rect=81%2C114%2C5381%2C3522&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/funny-woman-politely-covering-her-mouth-1900937419">Shutterstock</a></span></figcaption></figure><p>We all get hiccups from time to time, and sometimes they just won’t seem to go away. </p>
<p>Hiccups are <a href="https://pubmed.ncbi.nlm.nih.gov/8947969/">involuntary contractions</a> of the diaphragm – the muscle separating your chest from your abdomen, which plays a key role in breathing – followed by a sudden closure of the vocal cords. </p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5677923/">medical term</a> for hiccups is singultus. This derives from the Latin word <em>singult</em> which means “to catch ones breath while sobbing”. </p>
<p>For most of us, hiccups are annoying and don’t last that long. But for some people, they can be persistent, lasting more than two days. </p>
<p>The good news is, there are simple ways to alleviate regular hiccups – and treatments for when they persist. </p>
<h2>What causes hiccups?</h2>
<p>Hiccups are caused by a <a href="https://pubmed.ncbi.nlm.nih.gov/1592073/">reflex arc</a>: a neuromotor pathway that translates a sensation into a physical response. The sensations in this arc come from the brain, ear, nose and throat, diaphragm and organs in the chest and abdomen. </p>
<p>The sensation signals travel to a part of the brain which, along with the top of the spinal cord, is known as the “hiccup centre”. </p>
<p>From the hiccup centre, the signals travel back out to the diaphragm and the muscles that lay between your ribs (intercostal muscles), causing them to twitch. </p>
<p>The twitching of these muscles draws air into the lungs and this sudden inhalation makes the opening between the vocal cords, or glottis, close tightly shut. This rapid closure makes the “hic” sound. </p>
<figure class="align-center ">
<img alt="Sonographer persons pregnancy ultrasound" src="https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Even fetuses get the hiccups.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/professional-doctor-screening-pregnant-woman-by-594048134">Shutterstock</a></span>
</figcaption>
</figure>
<p>Anything that affects the arc can lead to hiccups. The <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">most common</a> is stretching the stomach from eating a large meal or drinking soft drinks. This means sensation signals from the stomach can trigger off the reflex arc. </p>
<p>Consuming hot chilli pepper, alcohol, smoking, and over-excitement can also <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">trigger</a> the reflex arc, leading to hiccups. </p>
<p>Hiccups have even been <a href="https://pubmed.ncbi.nlm.nih.gov/7383483/">observed</a> in healthy fetuses during prenatal ultrasound checks. In fact, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1891574/pdf/v041p00712.pdf">some researchers</a> believe hiccups are a mechanism to help prepare the lungs for breathing shortly after birth. </p>
<h2>How long will they last? And what can you do about them?</h2>
<p>An attack of hiccups that lasts less than 48 hours is generally <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">unconcerning</a>. Such an attack usually ends by itself. </p>
<p>Where it doesn’t resolve by itself, there are <a href="https://pubmed.ncbi.nlm.nih.gov/25055206/">ways</a> to suppress the reflex arc. The <a href="https://my.clevelandclinic.org/health/treatments/23209-valsalva-maneuver">Valsalva manoeuvre</a>, consuming ice-cold drinks and gentle eyeball pressure are thought to increase the activity of a long nerve (vagus) to the brain. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=856&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=856&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=856&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1076&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1076&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1076&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Manoeuvres such as rebreathing into a paper or plastic bag work by <a href="https://pubmed.ncbi.nlm.nih.gov/29729130/">increasing the carbon dioxide concentration</a> in the blood. This <a href="https://pubmed.ncbi.nlm.nih.gov/22523721/">helps to suppress</a> the movements of the muscles associated with hiccups. However, rebreathing carries a small but serious risk of <a href="https://www.sciencedirect.com/science/article/abs/pii/S0196064489805153">heart attack</a> so should only be performed under medical supervision. </p>
<p>However there is <a href="https://www.tandfonline.com/doi/full/10.1080/0964704X.2019.1708161">very limited evidence</a> to show these manoeuvres and interventions work. </p>
<h2>When should we get worried about hiccups?</h2>
<p>If hiccups last <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3006663/">longer than two days</a>, they are called persistent hiccups. If they <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3006663/">last beyond two months</a> they are known as intractable hiccups.
Persistent and intractable hiccups, known collectively as chronic hiccups, can be quite distressing and may signify a serious underlying cause, so it’s important to see your doctor. </p>
<p>People with chronic hiccups will undergo a comprehensive investigation. Their medical history will often give valuable clues to triggers. Certain medications such as anti-epileptic drugs, alcohol, smoking and recreational drug use are <a href="https://pubmed.ncbi.nlm.nih.gov/28759492/">all associated</a> with hiccups. </p>
<p>As organs in the chest and abdomen are involved in the reflex arc, <a href="https://pubmed.ncbi.nlm.nih.gov/28759492/">investigations of these organs</a> such as lung imaging or upper endoscopy (where a tube with a tiny camera is inserted into the throat to view the upper digestive tract), may be required.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/20427147/">One study</a> from France found 80% of patients with chronic hiccups had abnormalities in their oesophagus and stomach, with reflux disease being the most common finding. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-gastric-reflux-18791">Explainer: what is gastric reflux?</a>
</strong>
</em>
</p>
<hr>
<p>Your clinician will also inspect your <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">ear, nose and throat</a>, as irritation of the ear by a foreign body or infection of the throat can be triggers for hiccups. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">Imaging of the brain</a> may be necessary, especially if there are concerning signs such as changes in speech and weakness of facial and limb muscles. </p>
<figure class="align-center ">
<img alt="Iced water on a table" src="https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Drinking ice cold water helps some people.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/xUmStcovVvY">Giorgio Trovato/Unsplash</a></span>
</figcaption>
</figure>
<h2>How are chronic hiccups treated?</h2>
<p>After a thorough investigation, the underlying cause should be treated, where possible. </p>
<p>People suffering from hiccups often have problems with <a href="https://pubmed.ncbi.nlm.nih.gov/20427147/">gastric reflux</a>, so treatment may include a short course of anti-reflux medication. </p>
<p>Other medications with a strong evidence base that are used to treat hiccups include the anti-nausea drug <a href="https://pubmed.ncbi.nlm.nih.gov/25069531/">metoclopramide</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/25052238/">baclofen</a>, which is used to treat muscle spasticity (excessive tightness or tone).</p>
<p>There is <a href="https://pubmed.ncbi.nlm.nih.gov/28759492/">emerging evidence</a> that gabapentin, used to treat seizures, may also be effective for hiccups. </p>
<h2>What treatments might we see in future?</h2>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/35760460/">Researchers</a> have recently developed a rigid drinking tube with an inlet valve that requires active suction effort to draw water from a cup into the mouth. This tube has been called <a href="https://hiccaway.com/">forced inspiratory suction and swallow tool</a>, or FISST. </p>
<p>FISST is thought to stop the hiccup reflex arc by stimulating the sensory nerves to cause contraction of the diaphragm and glottis. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1408954166714667019"}"></div></p>
<p>In <a href="https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2781196">one study</a>, of the 249 participants who trialled FISST, just over 90% reported results better than home remedies. </p>
<p>However, the FISST research so far hasn’t compared it to a control group who didn’t receive the treatment, so it’s unclear how much more effective it is than a placebo, or dummy version. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-we-burp-137493">Curious Kids: why do we burp?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/196557/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vincent Ho does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There are simple ways to alleviate regular hiccups – and treatments for when they persist.Vincent Ho, Associate Professor and clinical academic gastroenterologist, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1965252023-01-05T11:54:10Z2023-01-05T11:54:10ZUrban light pollution is a danger for marine ecosystems – new research<figure><img src="https://images.theconversation.com/files/501350/original/file-20221215-15-2eals8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5982%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artificial light is an emerging threat for marine ecosystems in coastal waters (Kochi, India).</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/marine-drive-kochi-kerala-india-784637686">Vinu Sebastian/Shutterstock</a></span></figcaption></figure><p>Cities are artificially lit to allow humans to make use of the night. This light pollution means that stars are often barely visible in urban skies. But reduced stargazing is not the only <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.13927">impact of artificial light at night</a>. </p>
<p>Urban development in coastal areas is increasingly exposing marine ecosystems to artificial light. This exposure is particularly acute in and near some of the world’s largest coastal cities and may carry physiological and behavioural consequences for the organisms that inhabit their coastal waters. </p>
<p>The <a href="https://pml.ac.uk/">Plymouth Marine Laboratory</a>, where I lead the Marine Biogeochemistry team, last year published an atlas of <a href="https://online.ucpress.edu/elementa/article/9/1/00049/119144/A-global-atlas-of-artificial-light-at-night-under">artificial light at night under the sea</a>. The atlas reveals that at a depth of 1 metre, light pollution affects 1.9 million sq km of the world’s coastal seas. This is equivalent to 3.1% of global <a href="https://emodnet.ec.europa.eu/en/map-week-%E2%80%93-exclusive-economic-zones#:%7E:text=This%20is%20called%20a%20country's,lies%20its%20Exclusive%20Economic%20Zone.">exclusive economic zones</a> (the areas of the ocean owned by coastal nations). </p>
<p>Such research has confirmed that light pollution is widespread and expanding. But the difference between the intensity and cycles of natural and unnatural light has to this point been understudied. Quantifying this would allow a better understanding of the impact of expansive urbanised coastlines on the ecology of marine ecosystems. </p>
<p>Together with colleagues from the Universities of Plymouth and Strathclyde, <a href="https://online.ucpress.edu/elementa/article/10/1/00042/194863/Disruption-of-marine-habitats-by-artificial-light">we quantified</a> the magnitude of the natural and unnatural light reaching the marine ecosystems of a group of seven coastal cities with more than 10 million inhabitants: Tokyo, Shanghai, Mumbai, New York, Buenos Aires, Lagos and Los Angeles. </p>
<p>Our research showed that for these cities, dosages of artificial light at night on the surface of the sea are up to six times greater than moonlight. Moonlight intensity only exceeded artificial lighting within a period of three days from the brightest full moons.</p>
<figure class="align-center ">
<img alt="Shanghai skyline at night from the sea." src="https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shanghai’s skyline illuminated at night.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/shanghai-bund-garden-bridge-lujiazui-skyline-190208075">ArtisticPhoto/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Illuminating coastal waters</h2>
<p>Our model, which included inputs for lunar, artificial light and both daylight and twilight solar sources alongside seasonal and tidal changes in the distribution of light, was applied to each city over the course of 2020. In 15-minute time intervals we then determined the intensity of these light sources both above the sea’s surface and in the intertidal zone. This refers to the points on the shore which are covered, generally twice a day, by the tide. </p>
<p>We also applied the model to Plymouth, a coastal city in the west of England with a population of 230,000. Natural and artificial light sources have been studied here from 2001 to 2020 in order to capture the variability in tidal and lunar cycles. This fieldwork allowed us to ensure that our model provided accurate predictions.</p>
<p>In Plymouth, artificial light at night dosages generally ranked sixth across all of the cities studied. The city has a relatively northerly latitude, meaning it has long nights during the autumn and winter months. Yet summertime full moons in Plymouth shine with an intensity close to that of artificial light because the moon is close to the horizon all night with a longer atmospheric path length.</p>
<p>But the marine ecosystems likely to be most affected by light pollution are those in the coastal waters of Los Angeles, New York, Buenos Aires, Shanghai and Mumbai. Factors including tidal range and water clarity interact with the high intensity brightness of artificial urban lighting to impact marine ecosystems in these locations.</p>
<h2>Impact on marine ecosystems</h2>
<p>Natural sources of light at night have seasonal cycles. Nighttime light exposure has therefore historically been dependent on the moon and its cycle of waxing, waning and elevation in the sky. Artificial light sources, in contrast, have a fixed position irrespective of the season and shine with the same intensity throughout the night and all year round. </p>
<p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16264">Scientific research</a> has shown that light pollution can mask the natural cycle of the moon and can affect coastal organisms. This occurs at a variety of scales, from a hyperlocal (underneath street lights) to a regional and even global scale.</p>
<p>Marine organisms, including coral reefs, rely on natural light cycles to regulate their physiological and biological processes. Several coral species simultaneously <a href="https://www.sciencedirect.com/science/article/pii/S0960982220315827">release their reproductive cells</a> – called gametes – on cues from the lunar cycle.</p>
<p>Key maintenance processes in coral, such as <a href="https://www.frontiersin.org/articles/10.3389/fphys.2021.695083/full">symbiosis</a>, can also be sensitive to artificial lighting. Symbiosis describes the close relationship between the two organisms that make up coral. </p>
<p>The spectral composition of artificial light at night (its red, green and blue light components) illuminating seafloor habitats may also disrupt <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.14146">visually guided ecological processes</a>. Predators that usually feed in the day such as the herring gull may be able to see prey that would ordinarily be camouflaged at night, such as marine snails. </p>
<figure class="align-center ">
<img alt="A yellow and black street sign warning people that turtles are nesting on the beach and that street lights will be turned off." src="https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artificial light can disorientate turtle hatchlings.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fort-lauderdale-florida-january-23-2014-175410500">Serenethos/Shutterstock</a></span>
</figcaption>
</figure>
<p>Illuminating coastal environments can also alter the bodily functions of many marine animals. Exposure to artificial light can reduce the <a href="http://dx.doi.org/10.1098/rsbl.2019.0272">reproductive success of fish</a>. And research has also found that it can <a href="http://dx.doi.org/10.1016/0006-3207(91)90053-C">disorientate turtle hatchlings</a> and affect their ability to reach the safety of the ocean.</p>
<p>Some species are highly sensitive to even low levels of light. The daily migration of zooplankton, which are a key part of the marine food chain, can be disrupted by artificial light. <a href="https://www.nature.com/articles/s42003-020-0807-6">Research in the Arctic</a> has observed that zooplankton move away from the working light of a ship at depths of at least 200 metres.</p>
<p>Measuring light pollution in nature is a challenge because of the low intensities of light encountered. This is particularly true at greater depths. </p>
<p>But overcoming these challenges is essential to facilitate a better understanding of the ecological impact of light pollution. Research such as ours will guide biologists on future research into the impact of light pollution on marine ecosystems. It will also provide urban planners with the information necessary to balance coastal urban development with the protection of marine ecosystems.</p><img src="https://counter.theconversation.com/content/196525/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Smyth receives funding from the UK Natural Environment Research Council (grants NE/S003568/1 and NE/X006271/1).</span></em></p>Artificial lighting from cities illuminates coastal waters and can change the physiology and behaviour of marine organisms.Tim Smyth, Head of Science: Marine Biogeochemistry and Observations, Plymouth Marine LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1830342023-01-04T19:22:03Z2023-01-04T19:22:03ZWhat happens to your body on a long-haul flight?<figure><img src="https://images.theconversation.com/files/466912/original/file-20220603-12-qlkzez.jpg?ixlib=rb-1.1.0&rect=442%2C0%2C4566%2C2046&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/passengers-wearing-protective-medical-masks-during-1721222605">Shutterstock</a></span></figcaption></figure><p>If crowded airports are a sign, Australians are keen to get back into the skies. And if you’re flying long haul, in a few years you could have an even longer option.</p>
<p>Qantas <a href="https://australianaviation.com.au/2022/05/video-inside-qantas-project-sunrise-a350-1000s/">has announced</a> from <a href="https://www.qantasnewsroom.com.au/media-releases/qantas-announces-project-sunrise-aircraft-order-for-non-stop-flights-to-australia/">late 2025</a>, it will fly passengers on non-stop flights from Australia’s east coast to London that would see you in the air for more than 19 hours in one stretch. That’s compared with current flights that take the best part of 24 hours but are broken up into shorter legs.</p>
<p>So what will happen to your body during one of these longer flights? Is it any different to what happens when you fly long-haul now?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/in-for-the-long-haul-the-challenge-to-fly-non-stop-from-australia-to-anywhere-in-the-world-85981">In for the long-haul: the challenge to fly non-stop from Australia to anywhere in the world</a>
</strong>
</em>
</p>
<hr>
<h2>1. You can become dehydrated</h2>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551461/">Dehydration</a> is common on long-haul flights. It can explain why your throat, nose and skin can feel dry on an aeroplane. The longer the flight, the greater the risk of dehydration.</p>
<p>That’s because of <a href="https://www.ncbi.nlm.nih.gov/books/NBK207472/">low levels of humidity</a> in the cabin compared with what you’d expect on the ground. This is mostly because a lot of the air circulating through the cabin is drawn from the outside, and there’s not a lot of moisture in the air at high altitudes.</p>
<p>You also risk dehydration by not drinking enough water, or drinking too much alcohol (alcohol is a diuretic, resulting in an increase in fluid lost).</p>
<p>So drink water before you jump on the plane. During the flight, you’ll also need to drink more water than you usually would.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Air steward picking up bottle of water from drinks trolley on plane" src="https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490580/original/file-20221019-15-atspyy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Make sure you drink enough water before and during the flight. But avoid drinking too much alcohol.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/stewardess-take-water-bottle-trolley-cart-1992757658">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-do-i-tell-if-im-dehydrated-107437">Health Check: how do I tell if I'm dehydrated?</a>
</strong>
</em>
</p>
<hr>
<h2>2. The cabin can play havoc with your ears, sinuses, gut and sleep</h2>
<p>As the cabin pressure changes, the gas in our bodies reacts accordingly. It expands as the aircraft climbs and pressure decreases, and the opposite occurs as we descend. This can lead to common problems such as:</p>
<ul>
<li><p><a href="https://my.clevelandclinic.org/health/diseases/17929-airplane-ear">earaches</a> – when the air pressure either side of your eardrum is different, placing pressure on the eardrum</p></li>
<li><p><a href="https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-017-0788-0">headaches</a> – can be caused by expanding air trapped in your sinuses</p></li>
<li><p>gut problems – just accept that you’re going to fart more.</p></li>
</ul>
<p>You can also feel more sleepy than usual. That’s due to the body not being able to absorb as much oxygen from the cabin air at altitude than it would on the ground. Slowing down is the body’s way of protecting itself, and this can make you feel sleepy.</p>
<p>The good news is that most of these problems won’t necessarily be more pronounced on longer flights. They’re mainly an issue as the plane climbs and descends.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-happens-when-you-hold-in-a-fart-98310">Health Check: what happens when you hold in a fart?</a>
</strong>
</em>
</p>
<hr>
<h2>3. You could develop blood clots</h2>
<p>Blood clots, associated with being immobile for long periods, are usually a big concern for passengers. These include clots that form in the leg (<a href="https://theconversation.com/explainer-what-is-deep-vein-thrombosis-11140">deep vein thrombosis</a> or DVT) that can travel to the lung (where it’s known as a <a href="https://www.mayoclinic.org/diseases-conditions/pulmonary-embolism/symptoms-causes/syc-20354647">pulmonary embolism</a>).</p>
<p>If you don’t move around on the plane, and the more of the following <a href="https://search.informit.org/doi/epdf/10.3316/informit.666315070819684">risk factors</a> you have, the greater the chance of blood clots developing:</p>
<ul>
<li><p>older age</p></li>
<li><p>obesity </p></li>
<li><p>previous history or a family history of clots </p></li>
<li><p>certain types of clotting disorders</p></li>
<li><p>cancer</p></li>
<li><p>recent immobilisation or surgery</p></li>
<li><p>pregnancy or recently given birth</p></li>
<li><p>hormone replacement therapy or oral contraceptive pill.</p></li>
</ul>
<p>According to a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9149067/">review</a> in 2022, combining data from 18 studies, the longer you travel, the greater the risk of blood clots. The authors calculated there was a 26% higher risk for every two hours of air travel, starting after four hours. </p>
<p>So what about the risk of clots on these longer flights? We won’t know for sure until we start studying passengers on them.</p>
<p>Until that evidence comes in, the current advice still applies. Keep moving, stay hydrated and limit alcohol consumption.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-deep-vein-thrombosis-11140">Explainer: what is deep vein thrombosis?</a>
</strong>
</em>
</p>
<hr>
<p>There’s also <a href="https://www.cochrane.org/CD004002/PVD_compression-stockings-preventing-deep-vein-thrombosis-dvt-airline-passengers">evidence</a> for wearing compression stockings to prevent blood clots. These stockings are said to promote blood flow in the legs and to help blood return to the heart. This would normally happen by muscle contractions from moving or walking.</p>
<p>A 2021 <a href="https://www.cochrane.org/CD004002/PVD_compression-stockings-preventing-deep-vein-thrombosis-dvt-airline-passengers">Cochrane review</a> combined the results of nine trials with 2,637 participants who were randomised to wear compression stockings (or not) on flights lasting more than five hours.</p>
<p>No participants developed symptomatic DVTs. But there was evidence people who wore the stockings considerably reduced their chance of developing clots without symptoms, and we know that any clot can potentially grow, move and subsequently, cause symptoms. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person putting on compression stockings" src="https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490582/original/file-20221019-26-5j0gnp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Compression stockings reduce your risk of developing a DVT, according to a review of the evidence.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-puts-compression-stocking-on-her-1712032240">Shutterstock</a></span>
</figcaption>
</figure>
<p>So if you are concerned about your risk of developing blood clots, see your GP before you fly.</p>
<p>Usually if you do develop a blood clot, you won’t know about it until after the flight, as the clot takes time to form and travel. So keep an eye out for symptoms after the flight – pain and swelling in a leg (often just the one), chest pain, coughing and shortness of breath. And seek emergency health care if you do.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/blood-clots-five-reasons-they-may-happen-157197">Blood clots: five reasons they may happen</a>
</strong>
</em>
</p>
<hr>
<h2>4. Then there’s jet lag, radiation, COVID</h2>
<p>Then there’s <a href="https://www.mayoclinic.org/diseases-conditions/jet-lag/symptoms-causes/syc-20374027#:%7E:text=Drink%20plenty%20of%20water%20before,it's%20nighttime%20at%20your%20destination.">jet lag</a>, which is a stranger to few of us. This is a disconnect between the time your body thinks it is and the time by the clock, as you cross time zones.</p>
<p>Longer flights mean you are more likely (but not always) to cross more time zones. Jet lag will usually become more problematic when you cross three or more, especially if you’re travelling east.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/travelling-these-holidays-follow-tips-the-socceroos-use-to-conquer-jet-lag-87582">Travelling these holidays? Follow tips the Socceroos use to conquer jet lag</a>
</strong>
</em>
</p>
<hr>
<p>And if you take long-haul flights very often, it’s reasonable to assume that the longer you’re in the air, the greater the exposure to <a href="https://www.cdc.gov/niosh/topics/aircrew/cosmicionizingradiation.html">cosmic radiation</a>. As the name suggests, this is radiation that comes from space, which may increase the risk of cancer and reproductive issues. We don’t know what level of exposure is safe.</p>
<p>However, unless you fly frequently it’s unlikely to be a problem. If you’re pregnant or have other concerns, have a chat to your GP before you fly. </p>
<p>And don’t forget COVID. Take the usual precautions – wash your hands regularly, wear a mask and don’t fly if you’re unwell.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/want-to-cut-your-chance-of-catching-covid-on-a-plane-wear-a-mask-and-avoid-business-class-180333">Want to cut your chance of catching COVID on a plane? Wear a mask and avoid business class</a>
</strong>
</em>
</p>
<hr>
<h2>In a nutshell</h2>
<p>Research into how the body reacts to these longer, non-stop flights between Australia and Europe is in its early stages. <a href="https://www.qantasnewsroom.com.au/media-releases/qantas-to-operate-project-sunrise-research-flights-direct-new-york-london-to-australia/">Teams in Australia</a> are looking at this now.</p>
<p>Until then, if you’re taking a regular long-haul flight, the advice is relatively simple.</p>
<p>Follow the advice the airlines give you, and see your GP before you travel if necessary. During flight, make that extra effort to move about the cabin, drink water, wear a mask and practise good hand hygiene.</p>
<p>And see a doctor immediately for any worrying symptoms after your flight, as blood clots can take hours or even days to form, grow and move along your veins.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/which-medicines-dont-go-well-with-flying-90222">Which medicines don’t go well with flying?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/183034/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>I am a medical doctor specialising in General Practice and Aerospace Medicine, as well as a professional pilot currently working as a flight instructor and charter pilot across regional Australia. </span></em></p>No, you’re not imagining it. Your body does some weird things up in the air. Here’s a guide to the common and merely embarrassing to the rare, but serious.Tony Schiemer, Commercial Pilot | Aerospace Medicine Specialist | Clinical Lecturer, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1960162022-12-13T22:56:16Z2022-12-13T22:56:16ZWhy does the Alzheimer’s brain become insulin-resistant?<figure><img src="https://images.theconversation.com/files/499100/original/file-20221205-26-1etuem.jpg?ixlib=rb-1.1.0&rect=7%2C7%2C988%2C555&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Type 2 diabetes, characterised in its advanced stages by insulin resistance, is an important risk factor for Alzheimer's disease.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>As the population ages, the number of people with <a href="https://braininstitute.ca/research-data-sharing/neurodegenerative-disorders">neurodegenerative diseases</a>, such as <a href="https://alzheimer.ca/en/about-dementia/what-alzheimers-disease">Alzheimer’s disease</a>, increases. Approximately <a href="https://www.canada.ca/en/public-health/services/publications/diseases-conditions/dementia-highlights-canadian-chronic-disease-surveillance.html">75,000 Canadians</a> are diagnosed with Alzheimer’s disease each year and experience a decline in their cognitive abilities. The ordeal usually lasts for several years while their family members watch helplessly.</p>
<p>Neurodegenerative diseases are characterized by <a href="https://www.sciencedirect.com/science/article/abs/pii/S0924977X13001107">proteinopathies</a> — abnormal accumulations of proteins in the brain that impair the functioning of <a href="https://cancer.ca/en/cancer-information/resources/glossary/n/neuron">neurons</a>. The most widely studied therapeutic approach to developing drugs for Alzheimer’s is to try to reduce the aggregation of <a href="https://canjhealthtechnol.ca/index.php/cjht/article/view/eh0103/683">amyloid-beta peptide</a> and <a href="https://nouvelles.umontreal.ca/en/article/2022/10/20/unlocking-the-mysteries-of-tauopathies-a-protein-that-gives-hope/">tau protein</a> in neurons.</p>
<p>However, in order to reach their targets, the drugs must first cross the <a href="https://www.theglobeandmail.com/canada/article-toronto-researchers-look-at-new-approach-for-treating-alzheimers/">blood-brain barrier</a> (BBB) from the blood to the brain. This is because <a href="https://www.biorxiv.org/content/10.1101/2020.12.10.419598v1.full">endothelial cells</a>, cells that line the tiniest blood vessels in the brain, regulate the exchange between blood and the brain. They maintain a balance that allows access to essential molecules such as glucose, but restrict the passage of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3494002/">most pharmaceuticals</a>, including the new and <a href="https://www.ft.com/content/32478dbf-7270-4eb6-a576-663a47a3603e">much-hyped</a> drug <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2212948">lecanemab</a>.</p>
<p>When these brain endothelial cells become diseased, the balance is upset. The brain struggles to get the substances it needs back into the circulation and rejects those that might harm it.</p>
<p>The brain and the other organs of the body are thus in constant communication, while in health or in disease.</p>
<p>As experts in neurodegenerative diseases and the BBB, we have conducted a study on insulin receptor dysfunction in Alzheimer’s disease.</p>
<h2>Insulin and the brain</h2>
<p><a href="https://www.healthlinkbc.ca/health-topics/types-insulin">Insulin</a> is an essential hormone for life. It is best known for its effect on the regulation of <a href="https://www.diabetescarecommunity.ca/living-well-with-diabetes-articles/blood-sugar-levels-in-canada/?gclid=Cj0KCQiAyracBhDoARIsACGFcS4fee8N8dfBJj9HKxpUiGlNO6RANNF9BiZN52dsd6oxqgLCW7Od_WsaArF9EALw_wcB">blood sugar</a> and remains an essential part of the pharmaceutical treatment of <a href="https://www.healthlinkbc.ca/health-topics/types-insulin">diabetes</a>. In recent decades, researchers have noted vascular and metabolic abnormalities <a href="https://pubmed.ncbi.nlm.nih.gov/30022099/">in a high proportion of patients with dementia</a>.</p>
<p>Indeed, Type 2 diabetes, characterized in the later stages by <a href="http://www.diabetesclinic.ca/en/diab/1basics/insulin_resistance.htm">insulin resistance</a>, is a major risk factor for Alzheimer’s disease. There is some evidence to suggest that the <a href="https://pubmed.ncbi.nlm.nih.gov/29377010/">Alzheimer’s brain is less responsive to insulin</a>. Conversely, studies have shown that insulin can <a href="https://pubmed.ncbi.nlm.nih.gov/32730766/">improve memory</a>, prompting the development of clinical trials on the effect of insulin on Alzheimer’s disease.</p>
<p>Yet we still don’t know what cell types and mechanisms are involved in the action — and loss of action — of insulin in the brain. The vast majority of insulin is produced by the <a href="https://pancreaticcancercanada.ca/the-pancreas/">pancreas</a> and secreted into the bloodstream. Therefore, to affect the brain, insulin must first interact with the BBB and its endothelial cells, which are in contact with the blood and can take up insulin through <a href="https://pubmed.ncbi.nlm.nih.gov/36280236/">receptors</a>.</p>
<h2>Alzheimer’s and the insulin receptor</h2>
<p>In order to measure the amount of these insulin receptors in the brain, <a href="https://doi.org/10.1093/brain/awac309">we performed analyses directly in human tissues</a>. These samples came from a <a href="https://www.rushu.rush.edu/research/departmental-research/religious-orders-study">cohort</a> of over a thousand people who agreed to donate their brains after death. We have access to them through a partnership with researchers at Rush University in Chicago.</p>
<p>We found that the <a href="https://healthenews.mcgill.ca/new-insights-into-how-insulin-interacts-with-its-receptor/">insulin-binding receptor</a> is predominantly located in the microvessels, so, within the BBB itself. Moreover, the abundance of this receptor is decreased in Alzheimer’s patients. This decrease could lead to the loss of insulin response in the Alzheimer brain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="schematic" src="https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=781&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=781&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=781&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=982&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=982&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499093/original/file-20221205-15238-9izujo.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=982&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The brain insulin receptor is located mainly at the BBB, and its ability to respond to blood insulin is diminished in Alzheimer’s disease.</span>
<span class="attribution"><span class="source">(Manon Leclerc)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Insulin receptor dysfunction</h2>
<p>In order to better control the experimental variables and measure the response of the insulin receptor, we then tested our hypotheses in mice. The <em>in situ</em> cerebral perfusion technique consists of injecting insulin directly into the carotid artery (an artery located in the neck) so that it reaches the brain in its entirety. We have shown that circulating insulin mainly activates receptors located on the cerebral microvessels.</p>
<p>Although it was generally accepted that insulin crosses the BBB to reach cells such as neurons deeper in the brain tissue, our results show that the proportion of insulin that crosses the BBB is low.</p>
<p>These two observations thus confirm that the majority of insulin must interact with cells in the BBB before it can exert an action on the brain.</p>
<p>We then applied the same method to <a href="https://www.criver.com/products-services/research-models-services/genetically-engineered-model-services/transgenic-mouse-rat-model-creation/transgenic-mice?region=3601">transgenic mice</a>, which were genetically modified to model Alzheimer’s disease. We found that the response to insulin at the BBB was dysfunctional, with no activation of the insulin receptor in these diseased mice.</p>
<p>Thus, in both humans and rodents, the brain insulin receptor is located primarily at the BBB, and its ability to respond to blood insulin is impaired in Alzheimer’s disease.</p>
<h2>A significant breakthrough</h2>
<p>In sum, our results suggest that alterations in the number, structure and function of insulin receptors at the level of BBB endothelial cells may contribute to the cerebral insulin resistance observed in Alzheimer’s disease.</p>
<p>Alzheimer’s research efforts are currently focused on drugs that, in order to reach their therapeutic target, the neurons, must first cross the BBB, which severely restricts their passage. By targeting the metabolic dysfunction of the brain instead, we propose a research alternative that has two major advantages.</p>
<p>The first is that we can use treatments that do not have to cross the BBB barrier, since it is the endothelial cells themselves that become the therapeutic target. The second involves <a href="https://www.nature.com/articles/nrd.2018.168">“drug repurposing,”</a> which consists of taking advantage of the phenomenal therapeutic arsenal already approved to fight diabetes and obesity, but using this in the context of Alzheimer’s.</p>
<p>It should be remembered that the few drugs available to us provide only a modest improvement in symptoms. Combating insulin resistance in the brain would make it possible to break the vicious circle between neuropathology (disease that affects the brain) and diabetes, and in theory slow down the progression of the disease.</p>
<h2>The work is not finished</h2>
<p>On the basic research side, we will continue to study the mechanisms downstream from the microvessels to understand the action of insulin on the deep layers of the brain.</p>
<p>We hope that clinical research will follow suit with human studies to repurpose drugs that target certain metabolic diseases, such as diabetes, towards fighting Alzheimer’s.</p>
<p>In the meantime, while waiting for pharmaceutical solutions, each of us would do well to adopt the preventive cocktail that we all know well: a healthy diet combined with frequent physical and mental exercise.</p><img src="https://counter.theconversation.com/content/196016/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frederic Calon has received funding from: Canadian Institutes of Health Research (CIHR), Natural Sciences and Engineering Research Council of Canada (NSERC), Fonds de la recherche du Québec en santé (FRQS), Alzheimer Society of Canada.</span></em></p><p class="fine-print"><em><span>Manon Leclerc has received scholarships from the Fondation du CHU de Québec and the Fonds de Recherche du Québec - Santé (FRQS).</span></em></p><p class="fine-print"><em><span>Vincent Emond ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Impaired insulin receptors in the blood vessels between the blood and the brain may contribute to the insulin resistance observed in Alzheimer’s disease.Frederic Calon, Professeur, Université LavalManon Leclerc, PhD student, Université LavalVincent Emond, Professionnel de recherche, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1936132022-11-14T18:23:13Z2022-11-14T18:23:13ZWhy South Asians are at increased risk for diabetes: A complex interplay of genetics, diet and history<figure><img src="https://images.theconversation.com/files/493649/original/file-20221105-25-6t92cl.jpg?ixlib=rb-1.1.0&rect=2%2C2%2C1524%2C1020&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Person having their blood glucose level measured with a glucometer.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/why-south-asians-are-at-increased-risk-for-diabetes--a-complex-interplay-of-genetics--diet-and-history" width="100%" height="400"></iframe>
<p>In 2021, there were <a href="https://www.diabetesatlas.org">537 million adults living with diabetes</a>, of which approximately 90 per cent had Type 2 diabetes. When someone has Type 2 diabetes, specialized cells within the pancreas known as “beta cells” produce insufficient amounts of insulin.</p>
<p><a href="https://doi.org/10.1038%2Fs41591-021-01418-2">Insulin is a hormone</a> that travels through the bloodstream and tells other cells to take excess sugar out of the blood and use this sugar as energy, making sure the body keeps doing everything it needs to. </p>
<p>Individuals with Type 2 diabetes are “insulin resistant,” meaning cells do not adequately recognize insulin. These individuals require more insulin than normal to regulate blood sugar levels. When beta cells fail to compensate for the increased insulin demand, blood sugar levels rise, adversely affecting organ function.</p>
<p>Globally, the South Asian community is composed of over two billion individuals. In Canada, <a href="https://www.diabetes.ca/DiabetesCanadaWebsite/media/Advocacy-and-Policy/Backgrounder/2022_Backgrounder_Canada_English_1.pdf">14.4 per cent of South Asians have Type 2 diabetes</a>, the highest prevalence of any other ethnic group in the country.</p>
<p>As a member of the South Asian community, it is incredibly common for me (Lahari Basu) to learn that someone I know has been diagnosed with Type 2 diabetes. When I joined <a href="http://www.bruinlab.com/">Dr. Jenny Bruin’s lab</a> at Carleton University to study diabetes for my PhD, I was intrigued by this question: Why are South Asians disproportionately impacted by Type 2 diabetes?</p>
<p>That answer lies in a web of genetic, behavioural and cultural factors.</p>
<h2>Genetic variants</h2>
<p>In 2013, researchers confirmed that South Asians are particularly insulin resistant. Compared to Caucasians, <a href="https://doi.org/10.1016/j.metabol.2013.10.008">South Asians had higher insulin concentrations in their blood after ingesting sugar</a>. This means that South Asian individuals require more insulin to regulate their blood sugar levels, a characteristic of Type 2 diabetes.</p>
<p>There are numerous possible explanations for this, but genetic variants could be one culprit. Variation, or mutations, in genes can alter cell function. In the case of beta cells, genetic variants can lead to inappropriate levels of insulin secretion and insulin resistance.</p>
<figure class="align-center ">
<img alt="Cropped image of a young man in a plaid shirt holding an insulin pen" src="https://images.theconversation.com/files/494899/original/file-20221111-2672-d6vtg1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/494899/original/file-20221111-2672-d6vtg1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/494899/original/file-20221111-2672-d6vtg1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/494899/original/file-20221111-2672-d6vtg1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/494899/original/file-20221111-2672-d6vtg1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/494899/original/file-20221111-2672-d6vtg1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/494899/original/file-20221111-2672-d6vtg1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Individuals with Type 2 diabetes are insulin resistant, meaning cells do not adequately recognize insulin. Some people with Type 2 diabetes inject insulin with an insulin pen.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>It turns out that South Asians have <a href="https://doi.org/10.1038/s42003-022-03248-5">acquired mutations in various genes required for proper beta cell function</a>. They also have a higher prevalence of mutations in a <a href="https://doi.org/10.1038%2Fng.921">gene called GRB14</a>, resulting in increased insulin resistance.</p>
<p>Although not all South Asians have these mutations, a significant proportion do. There are also likely other gene variants that have yet to be uncovered in this population. These gene variants begin to paint an interesting picture of how genetic predisposition increases their risk of developing diabetes.</p>
<h2>Physiological adaptations</h2>
<p>Genetic variants only explain a small part of the increased insulin resistance in South Asian individuals. This observed insulin resistance may also have historical context.</p>
<p>South Asians have faced multiple famines throughout history. The recurrence of depleted food sources and malnutrition led to the development of a <a href="https://doi.org/10.2337%2Fdc11-0442">starvation adaptation</a>. This adaptation allowed them to efficiently process food and store fat during times of abundance, providing an advantage during famine.</p>
<p>Now, with urbanization and migration, this trait can be detrimental to South Asians. The adaptation does not bode well in a world with increased access to high-fat foods. Combined with modern-day diets, this adaptation can result in <a href="https://doi.org/10.1007/s00125-022-05803-5">increased fat storage and abdominal obesity in South Asian individuals</a>, leading to greater risk of insulin resistance and diabetes.</p>
<h2>Cultural differences</h2>
<p>Food plays an important social role in South Asian culture. For as long as I can remember, big family dinners were integral to my lifestyle and cultural identity. For us, food is a way to communicate, to honour ancestors and to celebrate.</p>
<p>The staples of South Asian cuisine include white rice, flatbreads and potatoes, with most cooking being done in clarified butter. This diet is influenced from a time before refrigerators and food abundance, focusing on shelf-stable, self-preserving foods. Diets high in carbohydrates and fat have been <a href="https://doi.org/10.1017/s0007114508073649">linked to increased insulin resistance and decreased metabolism</a> (the process of converting food into energy).</p>
<h2>Culture-centred treatment</h2>
<figure class="align-right ">
<img alt="A woman in a green shirt listening to a man in a white coat with his back to the camera" src="https://images.theconversation.com/files/494900/original/file-20221111-11-bzc8rr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/494900/original/file-20221111-11-bzc8rr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/494900/original/file-20221111-11-bzc8rr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/494900/original/file-20221111-11-bzc8rr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/494900/original/file-20221111-11-bzc8rr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/494900/original/file-20221111-11-bzc8rr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/494900/original/file-20221111-11-bzc8rr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Implementing treatment programs that focus on the culture of the patients can help approach diabetes management in a new light.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>There is clearly a complex relationship between South Asian ethnicity and diabetes risk. The interplay of culture and genetics presents a unique challenge for this community. For many, <a href="https://doi.org/10.1002/pdi.619">unfamiliarity with diabetes</a> may prevent them from getting the care they need.</p>
<p>Implementing <a href="https://doi.org/10.1186/s12992-019-0451-4">treatment programs that focus on the culture of the patients</a> can help approach diabetes management in a new light. Healthier versions of traditional foods, familiar languages and being cognizant of cultural barriers can help South Asians with diabetes understand the seriousness of the condition, their predisposition to it, and how to manage their symptoms.</p>
<h2>A call for South Asian-centric research</h2>
<p>As a South Asian woman studying diabetes, learning about this phenomenon opened my eyes to how little we know about ethnicity-specific diabetes risk. <a href="https://doi.org/10.1136%2Fbmjopen-2016-014889">South Asians are severely underrepresented in clinical research</a>. To truly understand the complex relationship between Type 2 diabetes and South Asians, it is vital to conduct clinical studies that specifically target this ethnic group.</p>
<p>A better scientific understanding of the link between South Asians and increased Type 2 diabetes and implementing culture-centred management programs can help alleviate the mystery and stigma behind this phenomenon.</p><img src="https://counter.theconversation.com/content/193613/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer Bruin receives funding from the Canadian Institutes of Health Research (CIHR), Natural Sciences and Engineering Research Council of Canada (NSERC), and JDRF. </span></em></p><p class="fine-print"><em><span>Lahari Basu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>In Canada, 14.4 per cent of South Asians have Type 2 diabetes, the highest prevalence of any other ethnic group in the country. Why is this population so disproportionately affected by diabetes?Lahari Basu, PhD Candidate, Department of Biology and Institute of Biochemistry, Carleton UniversityJennifer Bruin, Associate professor, Department of Biology and Institute of Biochemistry, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1886012022-08-18T01:20:30Z2022-08-18T01:20:30ZLying down, sitting, leaning over? What science says about the best way to take your medicine<figure><img src="https://images.theconversation.com/files/479516/original/file-20220817-18222-qj3sxa.jpg?ixlib=rb-1.1.0&rect=1%2C2%2C997%2C772&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-senior-man-taking-medicines-horizontal-62995330">Shutterstock</a></span></figcaption></figure><p>When pharmacists dispense tablets or capsules they commonly advise when and how often to take them, and if this needs to be with or without food. </p>
<p>You generally don’t hear them tell you to lean to one side when swallowing. But preliminary research from Johns Hopkins University in the United States <a href="https://aip.scitation.org/doi/full/10.1063/5.0096877">suggests</a> this might improve how fast your medicine is absorbed and gets to work.</p>
<p>The results are based on a computer simulation, rather than in actual patients, and may not equate to the real world. So it’s too early to suggest you strike a yoga pose when taking your medicine. </p>
<p>But your posture can be important when taking pills or capsules, for comfort or safety.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-time-of-day-should-i-take-my-medicine-125809">What time of day should I take my medicine?</a>
</strong>
</em>
</p>
<hr>
<h2>What happens when you swallow your medicine?</h2>
<p>Once you swallow a tablet or capsule, it moves down the throat to the stomach. There, a tablet swells and disintegrates, or a capsule breaks open. The drug can then dissolve and your body can absorb it.</p>
<p>Most drugs do not start being absorbed until they reach the small intestine. However, some drugs, such as aspirin, are likely to be absorbed in the stomach because of its acidic environment.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"726886205082595328"}"></div></p>
<p>A number of other factors can also affect where and how a drug is absorbed. </p>
<p>These include how fast the tablet disintegrates to release the drug, how fast the swallowed contents move from the stomach to the small intestine, the amount of food and drink consumed before taking the medicine, and how easily the drug is absorbed across the gut lining.</p>
<h2>How about this latest study?</h2>
<p>The US researchers <a href="https://publishing.aip.org/publications/latest-content/body-posture-affects-how-oral-drugs-absorbed-by-stomach/">used computer simulations</a> to investigate how posture affects how drugs <a href="https://aip.scitation.org/doi/full/10.1063/5.0096877">are absorbed</a>. </p>
<p>The researchers used software they developed to simulate several ways of taking a pill: staying upright, leaning to the left or right, or leaning backwards.</p>
<p>They showed leaning 45 degrees to the right favoured a faster movement of stomach contents into the duodenum (the first part of the small intestine). This would allow the pill to be absorbed more quickly and start to take effect.</p>
<p>The results could be important for medicines that you’d want to act quickly, such as pain medicines, or ones used to treat a heart attack. </p>
<p>There is already some <a href="https://pubmed.ncbi.nlm.nih.gov/18936930/">earlier evidence</a> from real patients suggesting posture may influence how medicines are absorbed. This includes the option of leaning to the right. But the authors acknowledge many factors influence absorption, not just posture.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-is-it-ok-to-chew-or-crush-your-medicine-39630">Health Check: is it OK to chew or crush your medicine?</a>
</strong>
</em>
</p>
<hr>
<h2>When is it best to sit or stand?</h2>
<p>Sometimes your pharmacist may advise you to swallow your medicine sitting, standing, or lying down for reasons other than speeding up absorption. </p>
<p>For example, certain drugs are more likely to cause side effects such as <a href="https://www.healthdirect.gov.au/gord-reflux">heartburn</a>, where stomach acid leaks from the stomach and moves up into the oesophagus (food pipe).</p>
<p>These include non-steroidal anti-inflammatory drugs, such as <a href="https://www.healthdirect.gov.au/ibuprofen">ibuprofen</a> (Nurofen), <a href="https://www.healthdirect.gov.au/medicines/medicinal-product/aht,20761/diclofenac">diclofenac</a> (Voltaren), and iron supplements. </p>
<p>So if this is a problem for you, it may help to take these medicines sitting or standing, and not lying down straight away afterwards. That’s because your stomach acid is less likely to leak back up into your oesophagus. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Elderly woman sitting down at table with pill and cup" src="https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479518/original/file-20220817-1490-bjhdxn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some medicines can irritate the throat or cause heartburn. So it’s best to take these upright.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/old-woman-taking-pills-her-country-218558989">Shutterstock</a></span>
</figcaption>
</figure>
<p>Some medicines can irritate the throat if they become stuck. This is because they damage the protective mucosal barrier that lines your oesophagus and stomach, causing irritation and inflammation. </p>
<p>For these medicines it is important to take these sitting up or standing, and remaining upright for 30 minutes afterwards.</p>
<p>These include the antibiotic <a href="https://www.healthdirect.gov.au/doxycycline">doxycycline</a>, and drugs known as bisphosphonates (for osteoporosis), such as <a href="https://www.healthline.com/health/drugs/risedronate-oral-tablet">risedronate</a> (Actonel) and <a href="https://www.healthdirect.gov.au/medicines/brand/amt,39580011000036106/alendronate-sandoz">alendronate</a> (Fosamax).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-older-people-get-osteoporosis-and-have-falls-68145">Why older people get osteoporosis and have falls</a>
</strong>
</em>
</p>
<hr>
<h2>How about lying down?</h2>
<p><a href="https://www.healthdirect.gov.au/medicines/brand/amt,3285011000036105/nitrolingual">Glyceryl trinitrate</a> (Nitrolingual) is an under-the-tongue spray. It’s prescribed to people with <a href="https://www.heartfoundation.org.au/bundles/your-heart/angina">angina</a>, a type of chest pain caused by an underlying heart problem. </p>
<p>Pharmacists advise patients to sit or lie down before using this spray as it can cause a sudden drop in blood pressure, making you feel very dizzy. </p>
<p>Other heart medicines, such as diuretics, are also known to cause dizziness. Although you don’t usually need to take these medications lying down, if you do become dizzy it is best to sit or lie down, and ensure you stand up slowly afterwards.</p>
<p>There are also <a href="https://www.medsafe.govt.nz/profs/puarticles/march2017/medicineinducedvertigo.htm">medications</a> that can cause drowsiness or make you feel “woozy”. These can include strong pain killers (such as opiates), sleeping tablets, some epilepsy medications, or drugs for certain mental health conditions, such as anxiety or schizophrenia. </p>
<p>These don’t need to be swallowed while lying down, but lying down can help if you become dizzy or drowsy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Woman lying on side in bed holding glass of water and a pill" src="https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479519/original/file-20220817-18377-wztyfz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some medicines can make you dizzy. So you can lie down after taking them.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mature-woman-taking-medicine-home-closeup-776225686">Shutterstock</a></span>
</figcaption>
</figure>
<h2>What if I’m not sure?</h2>
<p>Next time your pharmacist dispenses your medicine, unless they provide specific guidance about sitting, standing or lying down, you are generally safe to take it whichever way is most comfortable.</p>
<p>So how about this latest evidence suggesting leaning to the right might help? At this stage, you likely won’t hear your doctor or pharmacist recommend you should lean over to take your medicines until further research is done. </p>
<p>But next time you need to take a medicine for pain, as long as it is not uncomfortable, feel free to try this to see if your pain is relieved faster.</p><img src="https://counter.theconversation.com/content/188601/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elise Schubert is a registered pharmacist and a PhD Candidate receiving scholarship from the University of Sydney and Canngea Pty Ltd.</span></em></p><p class="fine-print"><em><span>Associate Professor Wheate in the past has received funding from the ACT Cancer Council, Tenovus Scotland, Medical Research Scotland, Scottish Crucible, and the Scottish Universities Life Sciences Alliance. He is a Fellow of the Royal Australian Chemical Institute, a member of the Australasian Pharmaceutical Science Association, and member of the Australian Institute of Company Directors. Nial is the science director of Canngea Pty Ltd, chief scientific officer of Vairea Skincare LLC, and a Standards Australia panel member for sunscreen agents.</span></em></p><p class="fine-print"><em><span>Associate Professor Tina Hinton has previously received funding from the Schizophrenia Research Institute (formerly Neuroscience Institute of Schizophrenia and Allied Disorders). She is currently a Board member of the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists. </span></em></p>Sometimes, it’s best to take your medicine sitting up. Other times, lying down is safer. Here’s what we know so far.Elise Schubert, Pharmacist and PhD Candidate, University of SydneyNial Wheate, Associate Professor of the Sydney Pharmacy School, University of SydneyTina Hinton, Associate Professor of Pharmacology, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1833542022-05-24T03:10:02Z2022-05-24T03:10:02ZWhy do my armpits smell? And would using glycolic acid on them really work?<figure><img src="https://images.theconversation.com/files/464442/original/file-20220520-25-f6x9om.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5760%2C3819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>You showered this morning, are wearing fresh clothes and having an otherwise normal day, when suddenly you notice <em>that</em> stench. </p>
<p>Why do our armpits smell, and why more at some times than others? </p>
<p>It all comes down to an oily secretion from special glands beneath our skin, which are very prevalent under the armpits, and more active at certain times.</p>
<p>And despite what you might have heard on Instagram or TikTok, wiping under your arms with glycolic acid is not the best long-term solution.</p>
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<strong>
Read more:
<a href="https://theconversation.com/explainer-why-do-i-sweat-so-much-and-how-can-i-stop-it-22060">Explainer: why do I sweat so much and how can I stop it?</a>
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<h2>The oily paste</h2>
<p>The main sweat glands (called “eccrine” sweat glands) covering most of our body secrete primarily water, which is odourless and evaporates to cool us down.</p>
<p>However, our body is also equipped with a second type of sweat gland, called “apocrine sweat glands”.</p>
<p>They’re mostly around areas with lots of hair follicles, such as the armpits and groin. These glands secrete an oily compound, and become more active in response to stress, fear, anxiety, pain, and sexual stimulation. </p>
<p>Initially odourless, this oily secretion provides great food for bacteria living on our skin.</p>
<p>The bacteria convert this sweat into <a href="https://asm.org/Articles/2021/December/Microbial-Origins-of-Body-Odor">fatty acids</a>, and compounds that produce scents, giving off an odour with smell traces reminiscent of onion, cumin, and rotten meat. </p>
<p>The type of bacteria is relatively consistent between people, but the balance between each type can be different.</p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0022202X1534687X">Genetics</a> play a prominent role in how we smell.</p>
<p>And because our apocrine glands respond to emotions, our thoughts and lifestyle can influence on their activity.</p>
<p>Even some foods, such a lot of <a href="https://academic.oup.com/chemse/article/31/8/747/364338">red meat</a>, can alter the smell.</p>
<p>For both men and women, underarm hair can also cause a more prominent <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4793925/">smell</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464438/original/file-20220520-18-bg50yc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Our apocrine glands respond to emotions.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-our-toes-and-fingers-get-wrinkly-in-the-bath-120229">Curious Kids: why do our toes and fingers get wrinkly in the bath?</a>
</strong>
</em>
</p>
<hr>
<h2>But what’s the role of this smell?</h2>
<p>Apocrine sweat glands don’t generally activate until puberty, which is why body odour isn’t really a concern when we’re young.</p>
<p>The scent also changes with the production of hormones.</p>
<p>For example, during the menstrual cycle, the most “attractive” smell occurs around the time of <a href="https://academic.oup.com/beheco/article/15/4/579/205993">ovulation</a>, when women are <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1439-0310.2006.01125.x">most fertile</a>. However, the sexual function of body odour doesn’t appear to play a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6773238/">major role</a> in humans.</p>
<p>Nonetheless, there may be some social relevance to our unique scent. Newborn babies can recognise their mother’s armpit smells a few weeks <a href="https://pubmed.ncbi.nlm.nih.gov/4075877/">after delivery</a>, and mothers can distinguish the smell of their own baby by about <a href="https://academic.oup.com/chemse/article/31/8/747/364338">three weeks</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-causes-dry-lips-and-how-can-you-treat-them-does-lip-balm-actually-help-161264">What causes dry lips, and how can you treat them? Does lip balm actually help?</a>
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<h2>How to avoid the odour?</h2>
<p>Our sweat gland secretions are odourless, so the longer the bacteria on our skin have to process the oils, the more scented compounds they can produce. </p>
<p>That’s why showering every day helps reduce odour.</p>
<p>Antiperspirants reduce the amount of sweat released by the glands. This is usually due to ingredients such as aluminium, which form a temporary blockage in the glands.</p>
<p>Deodorants work to mask the odours with stronger, pleasant scents. They often also contain alcohols or ingredients that can turn your skin slightly acidic, or make the area less hospitable to bacteria.</p>
<p>Choose clothing wisely. If your skin is moist for a long time it gives bacteria a chance to grow. Clean clothes that allow for good airflow can help keep you smelling fresher for longer during the <a href="https://www.health.qld.gov.au/news-events/news/whats-the-go-with-body-odour">day</a>. </p>
<p>Caffeine, some medications, as well as some illicit drugs such as methamphetamine, MDMA, heroin and cocaine can increase sweating, which will affect body odour.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&rect=0%2C37%2C4991%2C3659&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&rect=0%2C37%2C4991%2C3659&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=445&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=445&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=445&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=559&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=559&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463858/original/file-20220518-16-50xwdr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=559&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Our sweat gland secretions are odourless, so the longer the bacteria on our skin has to process the oils, the more scented compounds it can produce.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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Read more:
<a href="https://theconversation.com/curious-kids-why-do-we-have-eyebrows-157047">Curious Kids: why do we have eyebrows?</a>
</strong>
</em>
</p>
<hr>
<h2>What about antiperspirants and glycolic acid?</h2>
<p>You may have heard antiperspirants containing aluminium could cause cancer. The Cancer Council has <a href="https://www.cancer.org.au/iheard/can-deodorants-and-antiperspirants-with-aluminium-cause-cancer">called</a> this a myth and a rumour, with <a href="https://www.cancer.gov/about-cancer/causes-prevention/risk/myths/antiperspirants-fact-sheet">no scientific studies</a> specifically linking the use of these products to <a href="https://www.cancer.org.au/iheard/can-deodorants-and-antiperspirants-with-aluminium-cause-cancer">cancer</a>.</p>
<p>Nonetheless, it is wise to consider the cosmetics or chemicals we put on our skin. If you find your antiperspirant or deodorant is causing irritation or rashes, try a product with different ingredients or consult a doctor.</p>
<p>A recent <a href="https://www.refinery29.com/en-au/tiktok-the-ordinary-glycolic-acid-natural-deodorant">trend</a> on Tik Tok and Instagram suggests using glycolic acid (often used as an exfoliant for the face) on the armpits to reduce smell.</p>
<p>Theoretically, adding this chemical to your armpit will alter the environment under the arms. This can inhibit bacteria growth, and assist to reduce body odour. However, it could irritate the skin, particularly under the arms where there is a lot of friction, and especially if the area was recently shaved.</p>
<p>It will also not inhibit the amount you sweat.</p>
<p>Glycolic acid straight from the bottle will not act for long, as sweat from the armpits will dilute and neutralise its activity. This means even if it works temporarily, you’ll likely be back to your odorous ways pretty soon.</p>
<p>If you’re aiming to avoid chemical products, the best steps to an odour-free life are the obvious ones. Shower daily with soap (and dry off thoroughly), wear breathable fabrics (like cotton, linen or moisture-wicking sportswear), keep your clothes clean, reduce stress and limit your caffeine intake.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-know-hand-dryers-can-circulate-germs-through-the-air-why-are-they-still-used-everywhere-157410">We know hand dryers can circulate germs through the air. Why are they still used everywhere?</a>
</strong>
</em>
</p>
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<p><em>Thank you to PhD Candidate Charlotte Phelps for her assistance with this article.</em></p><img src="https://counter.theconversation.com/content/183354/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christian Moro does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It all comes down to an oily secretion from special glands beneath our skin, which are very prevalent under the armpits, and more active at certain times.Christian Moro, Associate Professor of Science & Medicine, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1817032022-04-29T12:21:31Z2022-04-29T12:21:31ZGilbert Gottfried and the mechanics of crafting one of the most memorable voices of all time<figure><img src="https://images.theconversation.com/files/460333/original/file-20220428-12-yk51sc.jpg?ixlib=rb-1.1.0&rect=13%2C8%2C2982%2C1985&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Marlee Matlin covers her ears as Gottfried performs during the Comedy Central Roast of Donald Trump in 2011.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/ComedyCentralRoastofDonaldTrump/9f6393d4b209436788f830ae5dfd82cf/photo?Query=gilbert%20gottfried&mediaType=photo&sortBy=arrivaldatetime:desc&dateRange=Anytime&totalCount=154&currentItemNo=131">AP Photo/Charles Sykes</a></span></figcaption></figure><p>Though Gilbert Gottfried’s voice has alternatively been described as “<a href="https://variety.com/2022/film/news/gilbert-gottfried-dead-dies-comedian-aladdin-1235231387">shrill</a>,” “<a href="https://www.looper.com/132868/whatever-happened-to-gilbert-gottfried/">annoying</a>” and “<a href="https://www.cnn.com/2022/04/12/entertainment/gilbert-gottfried-death/index.html">grating</a>,” you can’t say it isn’t memorable.</p>
<p>Gottfried, <a href="https://www.nytimes.com/2022/04/12/arts/gilbert-gottfried-dead.html">who died on April 12, 2022</a>, didn’t naturally sound this way. Watch him perform as a cast member during on the sixth season of “<a href="https://www.youtube.com/watch?v=idtrUge0wAQ">Saturday Night Live</a>,” and you’ll hear a voice that sounds downright angelic by comparison. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/idtrUge0wAQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Gilbert Gottfried’s brief run as a cast member on ‘Saturday Night Live’ occurred before the development of his signature voice.</span></figcaption>
</figure>
<p>But as he developed his comic persona, that distinctive sound made its way into his performances in stand-up comedy, advertising, television and film – perhaps most famously as Iago in “<a href="https://www.imdb.com/title/tt0103639/?ref_=nv_sr_srsg_0">Aladdin</a>,” Mr. Peabody in “<a href="https://www.imdb.com/title/tt0100419/?ref_=nv_sr_srsg_2">Problem Child</a>” and as a <a href="https://www.youtube.com/watch?v=j8PGzYwTsqM">squawking duck</a> in advertisements for the insurance giant Aflac. </p>
<p>Clearly, Gottfried figured out how to create a character that perfectly synced a personality with a voice that matched – a particularly valuable skill for actors that requires a combination of technique and instinct.</p>
<h2>The smooth operators</h2>
<p>In 2001, the Center for Voice Disorders at Wake Forest University <a href="https://newsroom.wakehealth.edu/News-Releases/2002/01/Americans-Speak-Out-Select-the-Best-and-Worst-Voices-in-America-In-Online-Polling">surveyed Americans</a> asking them who possessed the best and worst voices. The actors with the three best voices were James Earl Jones, Sean Connery and Julia Roberts. </p>
<p>The worst? Leading the pack was Fran Drescher of “<a href="https://www.imdb.com/title/tt0106080/">The Nanny</a>” fame, followed by Roseanne Barr and – you guessed it – Gilbert Gottfried.</p>
<p><a href="https://sc.edu/study/colleges_schools/artsandsciences/theatre_and_dance/our_people/directory/tobolski_erica.php">As a voice specialist</a> who teaches acting, voice and speech, I work with students and clients who often want to sound more like Connery and Roberts, and less like Gottfried.</p>
<p>Three distinct subsystems are involved in vocal production: the larynx, <a href="https://medlineplus.gov/ency/imagepages/19708.htm">or voice box</a>, which houses the vocal folds; the lungs and diaphragm in breathing; and areas where sounds resonate, or the vocal tract.</p>
<p>Speaking well involves a mix of understanding this vocal anatomy, utilizing proper breathing techniques and learning how to speak without excess tension. Collectively, these elements are known as <a href="https://voicefoundation.org/health-science/voice-disorders/anatomy-physiology-of-voice-production/the-voice-mechanism/">the voice mechanism</a>. </p>
<p>If a student or client comes into a session seeking a more effective voice, it’s these fundamentals that will be addressed. When these elements work together, they create a balanced vocal quality, one that’s generally perceived as confident and professional – think <a href="https://www.youtube.com/watch?v=RIiNuLgUInk">Morgan Freeman</a>. </p>
<h2>Developing a character</h2>
<p>But there’s a special niche for voices that are unusual.</p>
<p>The very skills that an actor learns to create a melodious voice can also be manipulated for a character voice – which is exactly what Gottfried was able to do, along with other actors who developed memorable characters, such as Jim Carrey in “<a href="https://www.imdb.com/title/tt0110475/?ref_=vp_close">The Mask</a>” and Eartha Kitt as Yzma in “<a href="https://www.youtube.com/watch?v=IHA2rNGUusU">The Emperor’s New Groove</a>.” Meryl Streep has been especially adept at creating unique voices for a number of roles, but one that stands out to me is her portrayal of Margaret Thatcher in “<a href="https://www.youtube.com/watch?v=dnwG9lTd4-M">The Iron Lady</a>.”</p>
<p>Understanding what you can change – and how to change it – is the key. </p>
<p>In my voice-over class, for example, I introduce a range of vocal qualities that can be mined to develop new voices. Five of the most common are a hoarse voice, a breathy one, a creaky one – also known as <a href="https://www.youtube.com/watch?v=4L7-9N1xQZA">vocal fry</a> – a voice that incorporates hypernasality and one that accentuates hyponasality, which refers to how most people sound when they have a cold.</p>
<p>One of the best and most immediate ways to change your voice is by placing it in a specific resonating area of the body – such as the sinuses or throat – or by changing how the vocal folds vibrate. </p>
<p>In a class on character voice, I coach students to direct the sound of their voice into their nasal cavity for a hypernasal sound, and into the back of their throat, the pharyngeal cavity, for a hyponasal sound. </p>
<p>To trigger a hypernasal sound, you could quack like a duck – “Aflac!” – or mimic <a href="https://www.imdb.com/name/nm0002121/">Margaret Hamilton’s</a> Wicked Witch of the West from “The Wizard of Oz” with the phrase “I’ll get you, my pretty!”</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/OQ_g6NOo7yo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Wicked Witch of the West in ‘The Wizard of Oz’ possesses the hallmarks of the hypernasal sound.</span></figcaption>
</figure>
<p>For a hyponasal sound, pinch your nostrils together so no sound comes through the nasal passage, and you’ll sound like you have a stuffy nose. Widening the back of your throat while you speak will create a sound similar to that of Lenny from “Loony Tunes.” </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/bs-Q0JmWjj0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Sounding droopy and dopey like Lenny can involve accentuating a hyponasal sound.</span></figcaption>
</figure>
<p>Want to sound like <a href="https://www.imdb.com/name/nm0001413/">Julie Kavner’s</a> rendition of Marge Simpson, who speaks with a creaky voice? Relax your throat and say “uhhh” in a very low pitch. The vocal folds are short and thick and create a slow vibration. </p>
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<figcaption><span class="caption">Marge Simpson pushes back against suggestions that she sounds like Vice President Kamala Harris.</span></figcaption>
</figure>
<p>To achieve a breathy quality, sigh out an easy “hahhh” with half voice and half breath. Marilyn Monroe singing “<a href="https://www.youtube.com/watch?v=iH3oOVKt0WI">Happy Birthday</a>” to President John F. Kennedy captures this vocal quality perfectly. </p>
<p>If Gilbert Gottfried were to walk into my classroom and ask me to analyze his character voice, I would describe it as a combination of hypernasality and raspy, with a bit of stridency thrown in. He speaks in a relatively high pitch with little modulation and stays at a consistently high volume. </p>
<p>Of course, Gottfried perfected this sound, and it worked in tandem with his brand of humor. If you were to develop something similar, just make sure you could figure out when to hit the “off” switch.</p>
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<figcaption><span class="caption">Gilbert Gottfried as Mr. Peabody in ‘Problem Child.’</span></figcaption>
</figure>
<p>[<em>Over 150,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-150ksignup">Sign up today</a>.]</p><img src="https://counter.theconversation.com/content/181703/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erica Tobolski does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Though it was exceedingly grating, the late comedian was able to perfect a sound that worked in tandem with his brand of humor.Erica Tobolski, Professor of Theatre and Dance, University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1658672022-03-01T13:37:54Z2022-03-01T13:37:54ZWhat you eat can reprogram your genes – an expert explains the emerging science of nutrigenomics<figure><img src="https://images.theconversation.com/files/442404/original/file-20220124-23298-1b8yqek.jpg?ixlib=rb-1.1.0&rect=51%2C0%2C5700%2C3754&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Along with calories and nutrients, food can influence the genetic blueprints that shape who you are.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cropped-image-of-hands-preparing-food-on-table-royalty-free-image/664647131?adppopup=true">Maskot via Getty Images</a></span></figcaption></figure><p><a href="https://theconversation.com/lo-que-usted-come-puede-reprogramar-sus-genes-un-experto-explica-la-ciencia-emergente-de-la-nutrigenomica-202423">Leer en español.</a> </p>
<p>People typically think of food as calories, energy and sustenance. However, the latest evidence suggests that food also “talks” to our genome, which is the genetic blueprint that directs the way the body functions down to the cellular level. </p>
<p>This communication between food and genes may affect your <a href="https://doi.org/10.1016/j.tibs.2020.04.002">health, physiology and longevity</a>. The idea that food delivers important messages to an animal’s genome is the focus of a field known as <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/nutrigenomics">nutrigenomics</a>. This is a discipline still in its infancy, and many questions remain cloaked in mystery. Yet already, we researchers have learned a great deal about how <a href="https://doi.org/10.1016/j.tibs.2020.04.002">food components affect the genome</a>.</p>
<p>I am a <a href="https://sites.lsa.umich.edu/dus-lab/">molecular biologist</a> who <a href="https://scholar.google.com/citations?user=MbZxwzMAAAAJ&hl=en">researches the interactions</a> <a href="https://doi.org/10.1016/j.tem.2020.11.011">among food</a>, <a href="https://doi.org/10.1016/j.neuint.2021.105099">genes</a> and <a href="https://doi.org/10.3389/fnbeh.2021.746299">brains</a> in the effort to better understand how food messages affect our biology. The efforts of scientists to decipher this transmission of information could one day result in healthier and happier lives for all of us. But until then, nutrigenomics has unmasked at least one important fact: Our <a href="https://www.youtube.com/watch?v=FmKPgBoCgKU">relationship with food is far more intimate</a> than we ever imagined. </p>
<h2>The interaction of food and genes</h2>
<p>If the idea that food can drive biological processes by interacting with the genome sounds astonishing, one need look no further than a beehive to find a proven and perfect example of how this happens. Worker bees labor nonstop, are sterile and live only a few weeks. The queen bee, sitting deep inside the hive, has a life span that lasts for years and a fecundity so potent she gives birth to an entire colony. </p>
<p>And yet, worker and queen bees are genetically identical organisms. They become two different life forms because of the <a href="https://doi.org/10.1126/science.1153069">food they eat</a>. The queen bee feasts on <a href="https://doi.org/10.1038/nature10093">royal jelly</a>; worker bees feed on nectar and pollen. Both foods provide energy, but royal jelly has an extra feature: <a href="https://doi.org/10.1038/embor.2011.9">its nutrients can unlock the genetic instructions</a> to create the anatomy and physiology of a queen bee. </p>
<p>So how is food translated into biological instructions? Remember that <a href="https://doi.org/10.1016/j.tibs.2020.04.002">food is composed of macronutrients</a>. These include carbohydrates – or sugars – proteins and fat. Food also contains micronutrients such as vitamins and minerals. These compounds and their breakdown products can trigger <a href="https://doi.org/10.1016/j.tem.2020.11.011">genetic switches that reside in the genome</a>. </p>
<figure class="align-center ">
<img alt="Two shopping carts lined up, one filled with fruits and vegetables, the other with sweets and high-fat foods." src="https://images.theconversation.com/files/444859/original/file-20220207-25-1ick4pa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444859/original/file-20220207-25-1ick4pa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444859/original/file-20220207-25-1ick4pa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444859/original/file-20220207-25-1ick4pa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444859/original/file-20220207-25-1ick4pa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444859/original/file-20220207-25-1ick4pa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444859/original/file-20220207-25-1ick4pa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The field of nutrigenomics aims to decipher how different types of foods transmit different – and important – messages to our cells.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/healthy-vs-unhealthy-shopping-trolleys-royalty-free-image/108821364?adppopup=true">Peter Dazeley/The Image Bank via Getty Images</a></span>
</figcaption>
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<p>Like the switches that control the intensity of the light in your house, genetic switches determine how much of a certain gene product is produced. Royal jelly, for instance, contains compounds that <a href="https://doi.org/10.1038/embor.2011.9">activate genetic controllers</a> to form the queen’s organs and sustain her reproductive ability. In humans and mice, byproducts of the amino acid methionine, which are abundant in meat and fish, are known to influence genetic dials that are <a href="https://doi.org/10.1016/j.tibs.2020.04.002">important for cell growth and division</a>. And vitamin C plays a role in keeping us healthy by <a href="https://doi.org/10.3389/fgene.2021.675780">protecting the genome from oxidative damage</a>; it also promotes the function of cellular pathways that can repair the genome if it does get damaged.</p>
<p>Depending on the type of nutritional information, the genetic controls activated and the cell that receives them, the messages in food can influence <a href="https://doi.org/10.1038/nrm4048">wellness, disease risk and even life span</a>. But it’s important to note that to date, most of these studies have been conducted in animal models, like bees. </p>
<p>Interestingly, the ability of nutrients to alter the flow of genetic information can span across generations. Studies show that in humans and animals, <a href="http://dx.doi.org/10.1136/jmedgenet-2014-102577">the diet of grandparents</a> influences the activity of genetic switches and the disease risk and mortality of grandchildren. </p>
<h2>Cause and effect</h2>
<p>One interesting aspect of thinking of food as a type of biological information is that it gives new meaning to the idea of a food chain. Indeed, if our bodies are influenced by what we have eaten – down to a molecular level – then what the food we consume “ate” also could affect our genome. For example, compared to milk from grass-fed cows, the milk from grain-fed cattle has different amounts and types of <a href="https://doi.org/10.1186/1475-2891-9-10">fatty acids and vitamins C and A </a>. So when humans drink these different types of milk, their cells also receive different nutritional messages. </p>
<p>Similarly, a human mother’s diet changes the levels of fatty acids as well as vitamins such as B-6, B-12 and folate that are found in her breast milk. This could alter the type of nutritional messages reaching the baby’s own genetic switches, although whether or not this has an effect on the child’s development is, at the moment, unknown. </p>
<figure class="align-center ">
<img alt="A smiling young girl drinking a glass of milk through a straw." src="https://images.theconversation.com/files/444867/original/file-20220207-69470-1qxu7h7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444867/original/file-20220207-69470-1qxu7h7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444867/original/file-20220207-69470-1qxu7h7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444867/original/file-20220207-69470-1qxu7h7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444867/original/file-20220207-69470-1qxu7h7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444867/original/file-20220207-69470-1qxu7h7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444867/original/file-20220207-69470-1qxu7h7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Food information derived from animals – such as cow’s milk – is transferred to the person drinking the milk.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/girl-drinking-milk-royalty-free-image/75939350?adppopup=true">Image Source/DigitalVision via Getty Images</a></span>
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</figure>
<p>And, maybe unbeknownst to us, we too are part of this food chain. The food we eat doesn’t tinker with just the genetic switches in our cells, but also with those of <a href="https://doi.org/10.1126/science.1223813">the microorganisms living in our guts, skin and mucosa</a>. One striking example: In mice, the breakdown of short-chain fatty acids by gut bacteria <a href="https://doi.org/10.1096/fj.14-259598">alters the levels of serotonin</a>, a brain chemical messenger that regulates mood, anxiety and depression, among other processes.</p>
<h2>Food additives and packaging</h2>
<p>Added ingredients in food can also alter the flow of genetic information inside cells. Breads and cereals <a href="https://doi.org/10.3945/an.114.007443">are enriched with folate</a> to prevent birth defects caused by deficiencies of this nutrient. But some scientists hypothesize that high levels of folate <a href="https://doi.org/10.1093/ajcn/87.3.517">in the absence of other naturally occurring micronutrients</a> such as vitamin B-12 could contribute to the higher incidence of colon cancer in Western countries, possibly by affecting the <a href="https://doi.org/10.1093/ajcn/nqaa259">genetic pathways that control growth</a>. </p>
<p>This could also be true with chemicals found in food packaging. Bisphenol A, or BPA, a compound found in plastic, <a href="https://doi.org/10.1016/j.bbi.2011.02.005">turns on genetic dials</a> in mammals that are critical to development, <a href="https://doi.org/10.3390/ijms21165761">growth and fertility</a>. For example, some researchers suspect that, <a href="https://doi.org/10.1111/1541-4337.12388">in both humans and animal models</a>, BPA influences the age of sexual differentiation and decreases fertility by making genetic switches more likely to turn on.</p>
<p>All of these examples point to the possibility that the genetic information in food could arise not just from its molecular composition – the amino acids, vitamins and the like – but also from the agricultural, environmental and economic policies of a country, or the lack of them.</p>
<p>Scientists have only recently begun decoding these genetic food messages and their role in health and disease. We researchers still don’t know precisely how nutrients act on genetic switches, what their rules of communication are and how the diets of past generations influence their progeny. Many of these studies have so far been done only in animal models, and much remains to be worked out about what the interactions between food and genes mean for humans. </p>
<p>What is clear though, is that unraveling the mysteries of nutrigenomics is likely to empower both present and future societies and generations.</p><img src="https://counter.theconversation.com/content/165867/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Dus receives funding from the National Science Foundation, the National Institute of Health, the Sloan Foundation, the Rita Allen Foundation, and the Klingenstein Foundation. She is affiliated with The University of Michigan, Ann Arbor. She is on the Advisory Board for the Trends in Endocrinology & Metabolism journal, the Editorial Board for the Chemical Senses journal, and the Advisory Board for the University of Michigan Museum of Natural History.</span></em></p>Scientists are just beginning to decode the genetic messages in your food – and how that may affect your health.Monica Dus, Associate Professor of Molecular, Cellular, and Developmental Biology, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1729412022-02-02T13:07:37Z2022-02-02T13:07:37Z50-year-old muscles just can’t grow big like they used to – the biology of how muscles change with age<figure><img src="https://images.theconversation.com/files/443851/original/file-20220201-17-1pp1t44.jpg?ixlib=rb-1.1.0&rect=86%2C0%2C7971%2C5376&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Why is it harder to build muscle as you age?</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/senior-male-bodybuilder-flexing-his-biceps-royalty-free-image/1310652763?adppopup=true"> DjelicS/iStock via Getty Images</a></span></figcaption></figure><p>There is perhaps no better way to see the absolute pinnacle of human athletic abilities than by watching the Olympics. But at the Olympics – and at almost all professional sporting events – you rarely see a competitor over 40 years old and almost never see a single athlete over 50. This is because with every additional year spent on Earth, bodies age and muscles don’t respond to exercise the same as they used to. </p>
<p>I lead a team of scientists who study the health benefits of <a href="https://hnrca.tufts.edu/mission/">exercise, strength training and diet in older people</a>. We investigate how older people respond to exercise and try to understand the underlying biological mechanisms that cause muscles to increase in size and strength after resistance or strength training.</p>
<p>Old and young people build muscle in the same way. But as you age, many of the biological processes that turn exercise into muscle become less effective. This makes it harder for older people to build strength but also makes it that much more important for everyone to continue exercising as they age.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman spotting someone doing a bench press." src="https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443854/original/file-20220201-17-1ljwx0x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lifting weights and doing pushups and other strength training exercises cause muscles to grow in size and strength.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/wide-shot-of-woman-spotting-friend-bench-pressing-royalty-free-image/1346267080?adppopup=true">Thomas Barwick/Digital Vision via Getty Images</a></span>
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<h2>How the body builds muscle</h2>
<p>The exercise I study is the type that makes you stronger. Strength training includes exercises like pushups and situps, but also weightlifting and resistance training using bands or workout machines.</p>
<p>When you do strength training, over time, exercises that at first felt difficult become easier as your muscles increase in strength and size – a process called hypertrophy. Bigger muscles simply have larger muscle fibers and cells, and this allows you to lift heavier weights. As you keep working out, you can continue to increase the difficulty or weight of the exercises as your muscles get bigger and stronger.</p>
<p>It is easy to see that working out makes muscles bigger, but what is actually happening to the cells as muscles increase in strength and size in response to resistance training?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram showing how muscle contraction can move an arm." src="https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=607&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=607&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=607&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=763&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=763&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443857/original/file-20220201-27-l8le9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=763&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Muscles move your limbs and body by contracting or releasing.</span>
<span class="attribution"><a class="source" href="https://openstax.org/books/anatomy-and-physiology/pages/preface">J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix via OpenStax</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Any time you move your body, you are doing so by shortening and pulling with your muscles – a process called contraction. This is how muscles spend energy to generate force and produce movement. Every time you contract a muscle – especially when you have to work hard to do the contraction, like when lifting weights – the action causes <a href="https://doi.org/10.1038/s42255-020-00290-7">changes to the levels of various chemicals in your muscles</a>. In addition to the chemical changes, there are also specialized receptors on the surface of muscle cells that detect when you move a muscle, generate force or otherwise <a href="https://doi.org/10.1007/s00223-014-9921-0">alter the biochemical machinery within a muscle</a>. </p>
<p>In a healthy young person, when these chemical and mechanical sensory systems detect muscle movement, they turn on a number of specialized chemical pathways within the muscle. These pathways in turn trigger the production of more proteins that get incorporated into the muscle fibers and cause the muscle to increase in size.</p>
<p>These cellular pathways also turn on genes that code for specific proteins in cells that make up the muscles contracting machinery. This activation of gene expression is a longer-term process, with genes being <a href="https://doi.org/10.1016/j.cmet.2015.05.011">turned on or off for several hours</a> after a single session of resistance exercise. </p>
<p>The overall effect of these many exercise-induced changes is to cause your muscles to get bigger.</p>
<h2>How older muscles change</h2>
<p>While the basic biology of all people, young or old, is more or less the same, something is behind the lack of senior citizens in professional sports. So what changes in a person’s muscles as they age?</p>
<p>What my colleagues and I have found in our research is that in young muscle, a little bit of exercise produces a strong signal for the many <a href="https://doi.org/10.1152/ajpregu.00324.2003">processes that trigger muscle growth</a>. In older people’s muscles, by comparison, the <a href="https://doi.org/10.1152/japplphysiol.01383.2003">signal telling muscles to grow is much weaker</a> for a given amount of exercise. These changes begin to occur when a person reaches around 50 years old and become more pronounced as time goes on.</p>
<p>In a recent study, we wanted to see if the changes in signaling were accompanied by any changes in which genes – and how many of them – respond to exercise. Using a technique that allowed us to measure changes in thousands of genes in response to resistance exercise, we found that when younger men exercise, there are changes in the expression of more than 150 genes. When we looked at older men, we found <a href="https://doi.org/10.1096/fj.14-254490">changes in the expression of only 42 genes</a>. This difference in gene expression seems to explain, at least partly, the more visible variation between how young and old people respond to strength training.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An older woman in a swimsuit flexing and showing off muscles." src="https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443859/original/file-20220201-28-r1wl98.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Strength training can help maintain overall fitness and allow you to keep doing other things you love as you age.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/older-caucasian-woman-flexing-her-muscles-on-beach-royalty-free-image/526298515">Peathegee Inc via Getty Images</a></span>
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<h2>Staying fit as you age</h2>
<p>When you put together all of the various molecular differences in how older adults respond to strength training, the result is that <a href="https://doi.org/10.1093/gerona/glp146">older people do not gain muscle mass as well as young people</a>.</p>
<p>But this reality should not discourage older people from exercising. If anything, it should encourage you to exercise more as you age. </p>
<p>Exercise still remains one of the <a href="https://www.nia.nih.gov/health/exercise-physical-activity">most important activities older adults can do for their health</a>. The work my colleagues and I have done clearly shows that although the responses to training lessen with age, they are by no means reduced to zero.</p>
<p>We showed that older adults with mobility problems who participate in a regular program of aerobic and resistance exercise can <a href="https://doi.org/10.1001/jama.2014.5616">reduce their risk of becoming disabled by about 20%</a>. We also found a similar 20% reduction in risk of becoming disabled among <a href="https://doi.org/10.7326/M16-2011">people who are already physically frail</a> if they did the same workout program.</p>
<p>While younger people may get stronger and build bigger muscles much faster than their older counterparts, older people still get incredibly valuable health benefits from exercise, including improved strength, physical function and reduced disability. So the next time you are sweating during a workout session, remember that you are building muscle strength that is vital to maintaining mobility and good health throughout a long life.</p><img src="https://counter.theconversation.com/content/172941/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roger Fielding receives funding from USDA, NIH, Biophytis, Nestle', Lonza. </span></em></p>As people age, the chemical signaling pathways in muscles become less potent, and it gets harder to build muscle and maintain strength. But the health benefits of strength training only increase with age.Roger Fielding, Senior Scientist Team Lead Nutrition Exercise Physiology and Sarcopenia Team Jean Mayer USDA Human Nutrition Research Center on Aging, Professor of Medicine, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1756102022-01-27T19:01:09Z2022-01-27T19:01:09ZGut microbes help hibernating ground squirrels emerge strong and healthy in spring<figure><img src="https://images.theconversation.com/files/442826/original/file-20220126-27-13smcdk.jpg?ixlib=rb-1.1.0&rect=63%2C369%2C3142%2C1959&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When not hibernating, ground squirrels need to feast to store energy.</span> <span class="attribution"><a class="source" href="https://doi.org/10.1126/science.abh2950">Robert Streiffer</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Ground squirrels spend the end of summer gorging on food, preparing for hibernation. They need to store a lot of energy as fat, which becomes their primary fuel source underground in their hibernation burrows all winter long.</p>
<p>While hibernating, ground squirrels enter <a href="https://doi.org/10.1111/brv.12137">a state called torpor</a>. Their metabolism drops to as low as just 1% of summer levels and their body temperature can <a href="https://doi.org/10.1152/physrev.00008.2003">plummet to close to freezing</a>. Torpor greatly reduces how much energy the animal needs to stay alive until springtime.</p>
<p>That long fast comes with a downside: no new input of protein, which is crucial to maintain the body’s tissues and organs. This is a particular problem for muscles. In people, long periods of inactivity, like prolonged bed rest, <a href="https://doi.org/10.1186/s13728-015-0036-7">lead to muscle wasting</a>. But muscle wasting is minimal in hibernating animals. Despite as much as six to nine months of inactivity and no protein intake, they preserve muscle mass and performance remarkably well – a very handy adaptation that helps ensure a successful breeding season come spring.</p>
<p>How do hibernators pull this off? It’s been <a href="https://doi.org/10.1086/650471">a real head-scratcher</a> <a href="https://doi.org/10.1152/ajpregu.1991.261.5.R1214">for hibernation biologists for decades</a>. <a href="https://scholar.google.com/citations?user=TUVZbtcAAAAJ&hl=en&oi=ao">Our research</a> <a href="https://scholar.google.com/citations?user=zuJyGe8AAAAJ&hl=en&oi=ao">team tackled</a> this question by investigating how hibernating animals might be getting a major assist <a href="https://doi.org/10.1126/science.abh2950">from the microbes that live in their guts</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="small mammal curled into a ball, nestled in wood chips" src="https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The 13-lined ground squirrel shows minimal signs of muscle wasting, even after hibernating for up to six months.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1126/science.abh2950">Robert Streiffer</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>A nitrogen-recycling system</h2>
<p>We knew from previous research that a hibernator’s <a href="https://doi.org/10.1016/j.cbpa.2020.110875">gastrointestinal system undergoes dramatic changes</a> in its structure and function from summer feeding to winter fasting. And it’s not only the animals who are fasting all winter long – their gut microbes are, too. Along with our microbiology collaborators, we figured out that <a href="https://doi.org/10.1146/annurev-nutr-071816-064740">winter fasting changes the gut microbiome</a> quite a bit.</p>
<p>And then we wondered … could gut microbes play a functional role in the process of hibernation itself? Could certain bacteria help keep muscle and other tissues working when the mostly immobile animals aren’t eating?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="brown cow munching grass" src="https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=843&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=843&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=843&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microbes in their guts help ruminants, including cows, hold on to the nitrogen they need to build proteins.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/brown-cow-royalty-free-image/1219160750">Lemanieh/ iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Biologists had previously identified a clever trick in ruminant animals, such as cattle, that helps them survive times when protein intake in the diet is low or protein needs are especially high, such as during pregnancy. A process <a href="https://doi.org/10.1079/NRR200498">called urea nitrogen salvage</a> allows the animal to recoup nitrogen – a critical ingredient for building protein – that would otherwise be excreted in urine as the waste product urea. Instead, the urea’s nitrogen is retained in the body and used to make amino acids, the building blocks of proteins.</p>
<p>This salvage operation depends on the chemical breakdown of urea molecules to release their nitrogen. But here’s the kicker: Chemical breakdown of urea requires urease, an enzyme that animals do not produce. So how does a cow, for instance, get that nitrogen out of urea?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="ball and stick model of a chemical structure" src="https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A model of the urea molecule, with two nitrogen atoms (in blue) along with a carbon (gray), an oxygen (red) and four hydrogen (white) atoms.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/urea-molecule-royalty-free-illustration/147217473">LAGUNA DESIGN/Science Photo Library via Getty Images</a></span>
</figcaption>
</figure>
<p>It turns out certain microbes that are normal residents of animals’ guts can do just that. They make the urease enzyme and use it to chemically split urea molecules, freeing up the nitrogen, which becomes part of ammonia molecules. Microbes then absorb ammonia and use it to make new protein for themselves.</p>
<p>Peculiarities of the ruminant digestive system allow those animals to benefit greatly from this process. But for other animals – like hibernators and us – it was less clear whether and how the urea nitrogen could make its way into the animals’ bodies to support protein synthesis.</p>
<p>This was our challenge as scientists: Could we demonstrate urea nitrogen recycling in hibernators and show that it is particularly helpful to them the longer they fast?</p>
<h2>Our experimental game plan</h2>
<p>Using the 13-lined ground squirrel, <a href="https://doi.org/10.1126/science.abh2950">we designed experiments to investigate</a> key steps in urea nitrogen salvage.</p>
<p>First, we injected into the squirrel’s bloodstream urea molecules in which the two nitrogen atoms were replaced by a heavier form of nitrogen that naturally occurs only in tiny amounts in the body.</p>
<p>We were able to follow these heavier nitrogen atoms as the injected urea moved from the blood into the gut, then as microbial urease broke down the urea into its component parts, and finally into the squirrels’ tissue metabolites and proteins. Wherever we saw higher levels of the heavier form of nitrogen, we knew that urea was the source of the nitrogen, and therefore gut microbes had to be responsible for getting the urea nitrogen back into the animals’ bodies.</p>
<p>To confirm that the microbes were doing the nitrogen recycling, we compared squirrels that had normal gut microbiomes to squirrels that didn’t. We treated some animals with antibiotics to reduce gut microbes at three times of the year: summer; early winter, when they were one month into fasting and hibernation; and late winter, whwithen they were four months into fasting and hibernation.</p>
<p>In squirrels with normal microbiomes, we saw evidence of urea nitrogen salvage at each step of the process that we tested. But squirrels with depleted microbiomes displayed minimal urea nitrogen salvage. Our observations confirmed that this process was indeed dependent on the gut microbes’ ability to break down urea and liberate its nitrogen in the hibernators’ guts. Hibernators’ liver and muscle tissue incorporated the most urea nitrogen during late winter – that is, the longer they’d been hibernating and without food.</p>
<p>We also found that the ground squirrels contribute to this remarkable symbiosis. During hibernation, their gut cells increase production of proteins called urea transporters. These molecules are lodged in intestinal cell membranes and shepherd urea from the blood into the gut where the microbes that contain urease are found. This assist means that what little urea the animal makes during hibernation has an easier route to the gut.</p>
<p>Finally, we found that it wasn’t just squirrels who benefited from this process. The microbes too were using the urea nitrogen to build their own proteins, showing that urea nitrogen salvage provides both parties with this important molecular building block during the long winter fast.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Fal-vhNgxvs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Every few weeks, hibernating squirrels arouse temporarily, as seen in this time-lapse video. They don’t eat or drink or leave the burrow, but the short increase in body temperature lets enzymes like urease do their jobs.</span></figcaption>
</figure>
<h2>Could this kind of symbiosis help humans?</h2>
<p>This example of hibernator-microbe symbiosis has potential clinical applications. For example, undernourishment, which affects millions of people globally, leads to a progressive decline in muscle mass and compromises health. Sarcopenia, which is muscle wasting that is a natural part of aging, impairs mobility and makes people more susceptible to injury. A detailed understanding of how the hibernator nitrogen salvage system is most effective when the risk of tissue loss and muscle wasting is greatest could lead to new therapeutics to help people in similar situations.</p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>Another potential application is in human spaceflight, during which crew members experience <a href="https://doi.org/10.33549/physiolres.934550">high rates of muscle atrophy</a> because of a microgravity-induced suppression of muscle protein synthesis. Even the extensive exercise regime that astronauts undertake to offset this is insufficient. A microbiome-based countermeasure that facilitates muscle protein synthesis similar to the process we have observed in hibernators may be worth investigating.</p>
<p>These applications, though theoretically possible, are a long way from delivery. But studies in the 1990s demonstrated that humans are capable of <a href="https://doi.org/10.1097/01.mco.0000196142.72985.d3">recycling small amounts of urea nitrogen with the help of their gut microbes</a>. So the necessary machinery is in place – it just needs to be optimized.</p><img src="https://counter.theconversation.com/content/175610/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hannah V. Carey received funding from the U.S. National Science Foundation for this work.</span></em></p><p class="fine-print"><em><span>Matthew Regan receives funding from the Natural Sciences and Engineering Research Council of Canada and the Canadian Space Agency.</span></em></p>Months not eating or moving don’t result in muscle wasting and loss of function for animals that hibernate. New research found gut microbes help their hosts hold onto and use nitrogen to build proteins.Hannah V. Carey, Professor Emeritus of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonMatthew Regan, Assistant Professor of Biological Sciences, Université de MontréalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1738072022-01-12T16:13:38Z2022-01-12T16:13:38ZCover your face, wear a hat and stay hydrated to exercise safely through the winter<figure><img src="https://images.theconversation.com/files/439960/original/file-20220110-25-hc6fgv.jpg?ixlib=rb-1.1.0&rect=0%2C26%2C5835%2C3904&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cold weather exercise can keep us healthy, but there are risks.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Let’s face it, winter in Canada is a reality we can’t ignore. And for many of us, it means getting outside and into the cold for work, chores and exercise. But there are ways to improve your comfort and safety while being active outdoors in cold weather.</p>
<p>First off, “cold” is what physiologists (people who study human function and structure) call a “stressor,” which means your body recognizes cold as something it needs to accommodate to stay in homeostasis (when your body functions are steady). </p>
<p>We can immerse ourselves in different types of cold — including cold air and cold water — where the cold environment can be accentuated by wind and snow or rain. Here are some guidelines for exercising in cold air — there is different advice <a href="https://doi.org/10.1186/2046-7648-3-12">for cold-water swimming</a>.</p>
<p>If you have underlying heart conditions or high blood pressure, talk to your physician about how long you should stay outdoors and what sorts of activities are recommended for you in winter.</p>
<h2>Maintaining core temperature</h2>
<p>Interestingly, in a nude or semi-nude state your body starts to recognize cold as a stressor at about 28.5 C. At this air temperature, your body’s coping mechanisms kick in to ensure your core temperature is maintained. This is why when you step out of a shower, or have few clothes on (like laying on a beach in summer) you will often shiver. </p>
<p>Adding insulative clothing to your body lowers the temperature you start to sense cold stress. In cold weather environments, our bodies produce a lot of heat when using energy to move our muscles for activities like shovelling snow or cross-country skiing. So if we wear proper insulative clothing and do enough muscular work, we can feel quite comfortable — what is called thermal comfort — in cold to very cold weather. </p>
<p>However, there are still ways to reduce risk and improve comfort while exercising outside in cold weather. Here are some things to think about as you make decisions about exercise outdoors in the winter.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A group of people in winter athletic gear stretch" src="https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439963/original/file-20220110-23-seck51.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dressing appropriately for weather conditions can keep you safe and increase your enjoyment of activities.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Cover your skin</h2>
<p>Reduce your exposed skin, everywhere you can. The <a href="https://doi.org/10.1249/JSR.0000000000000907">recently updated guidelines from the American College of Sports Medicine</a> indicate that frostbite, which is a “direct freezing injury … of skin surface” can occur at just -3 C. Tissues with less blood flow, such as hands, feet and head are more vulnerable, especially when the cold air is extreme (less than -15 C air temperature or -27 C wind chill). </p>
<p>Frostbite can be accelerated by contact with cold materials (metal, snow, ice) and by wet skin. Wear insulative clothing that has a high wicking ability to draw moisture off skin, and keep your head, feet and hands covered at all times!</p>
<p>Your face should also be covered for a few reasons. Covering your cheeks, forehead, nose and neck improves regulation of thermal comfort, especially in windy conditions, making activities like tobogganing or alpine skiing more comfortable. The skin on your face can takes a real beating — <a href="https://doi.org/10.1007/s004210050060">even in moderately windy conditions, your face skin temperature can decrease 25 C</a>. </p>
<p>If you have some underlying chronic conditions, including high blood pressure or heart disease, you should cover your face. Exposing a bare face to cold — as little as -5 C — engages parts of the nervous system which can increase blood pressure. Simply wearing a toque and scarf <a href="https://doi.org/10.1007/s00421-009-1176-5">can reduce this increase</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a young child with bare hands and reddened fingertips in the snow" src="https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439962/original/file-20220110-22-71p8rz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Frostbite and frostnip, can result in severe health consequences if not treated quickly with appropriate medical care.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Protect your lungs and breath</h2>
<p>Our lungs are especially vulnerable to cold air environments, where exercise actually increases the stress on the lung in winter conditions. Your lungs, for good reason, want to warm and humidify the air we breathe to body temperature and 100 per cent humidity. They do a really good job of this at rest, but during exercise, it requires more effort to condition the air you breath in. </p>
<p>Add cold air on top of high breathing rates (as seen during exercise) and your lungs are really challenged to warm and humidify each breath. Cooling of the airway is associated with a nervous system response and drying of the airway is associated with an inflammatory response, both <a href="http://dx.doi.org/10.1136/bjsports-2012-091292">which can constrict the lung (often called cold air bronchoconstriction)</a>. </p>
<p>Cold weather activity at less than 0 C, at moderate exercise intensity (brisk walking pace), <a href="https://doi.org/10.1080/22423982.2019.1583528">also results in respiratory symptoms</a> including the very common runny nose and feeling irritated in the nose (itchy, burning sensation). For more intense exercise (like a hard run or cross-country ski) the symptoms increase, and can include excess mucous, productive cough (getting that mucous out) and unproductive cough (irritating cough), chest tightness (trouble breathing), wheeze and sore throat; <a href="http://dx.doi.org/10.1016/j.resp.2019.103262">these symptoms can persist up to 24 hours after a hard cold weather workout</a>. </p>
<p>You can take several actions to reduce these symptoms. First, slowing down your exercise intensity gives your body a chance to condition the air in each breath. Second, covering your mouth with a buff, scarf or <a href="https://skiwax.ca/collections/airtrim">cold-weather mask</a> can help some capture moisture to humidify the next breath in. Third, reducing your total exposure time in cold air, because even 30 minutes of moderate exercise can increase your symptoms and airway constriction. And finally, drink enough water during prolonged bouts of cold weather because you can lose up 100 millilitres of water per hour due to heavy breathing exercise in cold air.</p>
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<figcaption><span class="caption">The Mayo Clinic provides tips on exercising in the cold.</span></figcaption>
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<h2>Being prepared</h2>
<p>Being unprepared in cold weather increases your overall risk of hypothermia and other cold weather related injuries. In fact, more than half of deaths associated with natural weather events are due to cold weather — directly to accidental hypothermia (severe drop in core temperature leading to death) or when <a href="https://doi.org/10.1056/NEJMra1114208">hypothermia exacerbates a pre-existing condition</a>. Note that accidental hypothermia can also occur in moderate cold, <a href="https://doi.org/10.1139/H07-041">which potentially puts outdoor enthusiasts at risk</a>. </p>
<p>It is also well documented that consumption of alcohol is a major risk factor in accidental hypothermia, <a href="https://www.cdc.gov/nchs/data/nhsr/nhsr076.pdf">along with prolonged exposure and inadequate clothing</a>. Other cold weather injuries include frostbite and frostnip, which can result in severe health consequences <a href="https://www.aafp.org/afp/2019/1201/p680.html">if not treated quickly with appropriate medical care</a>. </p>
<p>I hope this has helped you better understand some of the physiology behind how humans interact with cold air environments. More importantly I hope you can use some of these tips to enhance your enjoyment and safety in the winter, especially when the temperature dips well below 0 C.</p><img src="https://counter.theconversation.com/content/173807/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Kennedy receives funding from MITACS. </span></em></p>Preparing for being active in cold weather can help keep us safe and increase our enjoyment.Michael Kennedy, Associate professor, Kinesiology, Sport, and Recreation, University of AlbertaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1646552021-09-13T12:14:14Z2021-09-13T12:14:14ZWhat happens when your foot falls asleep?<figure><img src="https://images.theconversation.com/files/417576/original/file-20210824-17-1ma6ikr.jpg?ixlib=rb-1.1.0&rect=494%2C1005%2C4994%2C2982&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">That pins-and-needles feeling can come from sitting in the same position for a while.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/legs-of-a-girl-wearing-dotted-socks-royalty-free-image/1195442823">Westend61 via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<blockquote>
<p><strong>What happens when your foot falls asleep? – Helen E., age 8, Somerville, Massachusetts</strong></p>
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<p>Imagine you’ve just sat down to watch your favorite TV show. You decide to snuggle in with your legs crisscrossed because you find it more comfortable that way.</p>
<p>When the episode ends, you try to stand up and suddenly your right foot isn’t working. At first you just can’t move it, then it feels like it has pins and needles all over it. For a minute or two it feels uncomfortable and weird, but soon enough you are able to stand up and walk around normally.</p>
<p>What just happened?</p>
<p><a href="https://scholar.google.com/citations?user=gn8ZiLMAAAAJ&hl=en&oi=ao">I’m an exercise physiologist</a> – a scientist who studies what happens to our bodies when we move and exercise. The goal of much of my research has been to understand how the brain talks to and controls the different parts of our bodies. When your foot falls asleep, there is something wrong with the communication between your brain and the muscles in that area.</p>
<p>Every time you decide to move your body, whether it’s standing up, walking around or playing sports, your brain sends signals to your muscles to make sure they move correctly. When the brain is unable to talk with a muscle or groups of muscles, some weird things can happen – including that part of your body getting that weird falling-asleep sensation.</p>
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<figcaption><span class="caption">An animation explains how the nervous system works.</span></figcaption>
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<p>It usually starts with a sense of numbness or tingling in that area. This sensation, which people often also call “pins and needles,” is technically known as <a href="https://www.racgp.org.au/afp/2015/march/paraesthesia-and-peripheral-neuropathy/">paresthesia</a>.</p>
<p>Some people mistakenly think a lack of blood flow causes this feeling. They imagine the “asleep” feeling happens when your blood, which carries nutrients all over your body, is unable to get to your foot. But that’s not right.</p>
<p>When your foot falls asleep, it’s actually because the <a href="https://doi.org/10.2165/00007256-200232060-00003">nerves that connect the brain to the foot</a> are getting squished thanks to the position you’re sitting in. Remember, it’s these nerves that carry messages back and forth to let your brain and your foot communicate with each other. If the nerves have been compressed for a little while, you won’t have much feeling in your foot because it can’t get its normal messages through to your brain about how it feels or if it’s moving.</p>
<p>Once you start to move around again, the pressure on the nerves is released. They “wake up” and you’ll start to notice a “pins and needles” feeling. Don’t worry, that feeling will only last for a few minutes and then everything will feel normal again.</p>
<p>Now comes the important question: Is this dangerous? Most of the time, when your foot, or any other body part, falls asleep, it is temporary and nothing to worry about. In fact, since it lasts for only a minute or two, you may not even remember it happened by the end of the day.</p>
<p>Even though it’s not causing any permanent damage, you might still want to avoid the uncomfortable feeling that comes when your foot falls asleep. Here are a couple of tips that may help:</p>
<ul>
<li>Switch your position often.</li>
<li>Don’t cross your legs for very long.</li>
<li>When you are sitting for a long time, try standing up every so often.</li>
</ul>
<p>You probably can’t 100% prevent your foot from ever falling asleep. So don’t worry when it happens every once in a while. It’ll go away pretty quickly – and maybe it can remind you of all the important brain messages your nerves are usually transmitting without your even noticing.</p>
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<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/164655/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Zachary Gillen does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An exercise physiologist explains how it’s a problem of communication between your brain and your body.Zachary Gillen, Assistant Professor of Exercise Physiology, Mississippi State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1668242021-09-03T01:20:59Z2021-09-03T01:20:59Z3 reasons why Paralympic powerlifters shift seemingly impossible weights<p>Many people viewed the Tokyo Olympics as the pinnacle of human physical achievement. However, Paralympic performances <a href="https://www.tandfonline.com/doi/full/10.1080/2159676X.2012.685102?casa_token=-KzC7booo6UAAAAA%3AXJFvPnhjGPNPl_veEi-J-4913PHa6AQ5JD-MPoGpSL7Vi_H91graW8xI9Taffo78WdrgzzJ-jh0uTHg">often receive less attention</a> despite amazing feats of strength, speed and endurance.</p>
<p>We’ve seen this with powerlifting, which is our area of interest. We’re working with para-athletes to learn more about how some can lift heavier weights than athletes without disabilities. </p>
<p>Here’s what we know so far.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-brief-history-of-the-paralympic-games-from-post-wwii-rehabilitation-to-mega-sport-event-64809">A brief history of the Paralympic Games: from post-WWII rehabilitation to mega sport event</a>
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<h2>Paralympic record breakers</h2>
<p>Many Paralympians out-perform athletes without disabilities in track and road races lasting longer than a minute.</p>
<p>One example is the men’s 800m <a href="https://www.abc.net.au/news/2021-08-24/what-are-the-classifications-for-the-tokyo-paralympics-/100378012">T54 class</a>, where athletes compete in a track wheelchair. Here, the Paralympic record is <a href="https://db.ipc-services.org/sdms/web/record/at/pdf/type/WR/category/out/gender/M/evt/008/age/senior">almost 11 seconds faster</a> than athletes <a href="https://www.worldathletics.org/records/by-category/world-records">without a disability</a>.</p>
<p>In the marathon, the Paralympic world record is a little over <a href="https://db.ipc-services.org/sdms/web/record/at/pdf/type/WR/category/road/evt/MAR/age/senior">1h 20min</a>, set in 1999. This remains <a href="https://www.worldathletics.org/records/by-category/world-records">over 40 minutes quicker</a> than the record for athletes without a disability.</p>
<p>However, athletes who use a wheelchair can maintain speed over longer distances, at least <a href="https://www.nzherald.co.nz/sport/can-disabled-athletes-outcompete-able-bodied-athletes/R3BIYPCSDQ7NQ77XPLDT5SK6LA/">in part</a> due to the advantage offered by purposely designed equipment and technology.</p>
<p>It’s the medium- and long-duration events, rather than the speed and strength sports, where Paralympic athletes tend to perform better than athletes without disabilities.</p>
<p>But there’s one exception — powerlifting.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-paralympics-strive-for-inclusion-but-some-rules-unfairly-exclude-athletes-with-severe-disabilities-166347">The Paralympics strive for inclusion. But some rules unfairly exclude athletes with severe disabilities</a>
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<h2>What’s so special about powerlifting?</h2>
<p>Paralympic powerlifters (or Para-powerlifters) have one or more impairments that would limit their ability to participate in traditional weightlifting. <a href="https://www.paralympic.org/powerlifting/classification">These include</a> impaired muscle function, co-ordination and movement of the hips and legs, or short stature. </p>
<p>They compete in classes according to their bodyweight and bench press as much weight as possible <a href="https://www.paralympic.org/powerlifting/rules">under strict criteria</a>. </p>
<p>Para-powerlifting world records are impressive. Some five out of eight female records and six out of eight male records would be held by Paralympians if they were compared directly to athletes without disabilities. </p>
<p>Our calculations are based on athletes in a similar weight class and compared Paralympians with those competing in <a href="https://www.powerlifting.sport">International Powerlifting Federation</a> competitions.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/first-person-how-the-paralympics-changed-my-life-65047">First person: how the Paralympics changed my life</a>
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</em>
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<p>Records continue to be broken. Take China’s <a href="https://www.paralympic.org/news/world-record-debut-guo-lingling-day-first-time-champions">Guo Lingling</a> who lifted 109kg in the female 41kg weight class at the Tokyo 2020 Paralympics. </p>
<p>This record is more than 2.6 times her bodyweight, a feat that <a href="https://www.tandfonline.com/doi/abs/10.1080/24748668.2018.1496393">would still be impressive</a> for an athlete without a disability during a squat, let alone the bench press.</p>
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<p>In the men’s competition, Paralympians can lift record-breaking weights <a href="https://www.paralympic.org/powerlifting/records">more than 3.8 times</a> their bodyweight. By comparison, the world record for a male athlete without a disability is <a href="https://www.powerlifting.sport/championships/records">about 3.3 times</a> his bodyweight.</p>
<h2>Why are Para-powerlifters so strong?</h2>
<p>Due to lower limb impairments, Para-powerlifters may have a distinct advantage when comparing how much they can lift per kilo of bodyweight. That is, in some instances, lower-limb weight may be significantly less due to poor muscle quality even though automatic bodyweight additions are applied to athletes with amputations.</p>
<p>However, world records are based on the greatest weight lifted in each weight class rather than weight lifted per kilo of bodyweight. This is what makes Para-powerlifting records even more impressive.</p>
<p>So, we’re working with Para-powerlifters to find out more. Here are our three top reasons why they might be able to lift such heavy weights.</p>
<p><strong>1. Leg position</strong></p>
<p>Para-powerlifting rules are similar to those for athletes without disabilities. However, the legs of all Para-powerlifters must be placed or strapped to top of the bench when performing the bench press, rather than on the ground.</p>
<p>But scientific research remains at odds as to how much <a href="https://www.hrpub.org/journals/article_info.php?aid=7784">the legs contribute</a> to powerlifting bench press performance. In fact, some research suggests upper-body muscles are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5765801">better engaged</a> when the legs are not placed on the ground.</p>
<p>In other words, the current evidence cannot say for certain whether leg position gives one group an advantage or disadvantage. We want to find out more.</p>
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<p><strong>2. Short stature may help</strong></p>
<p>In the bench press the athlete lowers the bar to the chest, then pushes it up until the arms are fully extended. A shorter stature may mean some Para-powerlifters have to move the weight a shorter distance away from the chest. By moving through a smaller range, the muscle may be able work better throughout the movement. </p>
<p>Shorter limbs may also make it easier for some Para-powerlifters to overcome the torque (a rotating force on the joints) when lifting the bar.</p>
<p>However, in athletes without a disability <a href="https://pubmed.ncbi.nlm.nih.gov/19826300/">arm length</a> is not a major predictor of bench press performance, and not all Para-powerlifters have a short stature. So, more research is needed.</p>
<p><strong>3. Focusing on the bench press</strong></p>
<p>Para-powerlifters also train solely to perform the bench press. However, many record breaking powerlifters without disabilities also compete in competitions that include <a href="https://twitter.com/IPF_tweet/status/1431587495750348803">the squat</a> <a href="https://twitter.com/IPF_tweet/status/1431236408543428613">and deadlift</a> exercise. </p>
<p>Perhaps focusing on the one event gives Para-powerlifters some advantage.</p>
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<h2>What can we make of this?</h2>
<p>Para-powerlifters show us not all superior world records are confined to endurance sports or influenced by technology. </p>
<p>They also highlight the importance of strength training for people with or without a disability.</p>
<p>Last of all, Para-powerlifters shift our perception of athletes with disabilities by highlighting their extraordinary sporting capabilities.</p><img src="https://counter.theconversation.com/content/166824/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Christopher Latella is currently collaborating with the International Paralympic Committee (Para powerlifting) on scientific research projects related to this article. He has previously (2013-2017) coached able-bodied powerlifting athletes competing in the International Powerlifting Federation. He co-leads a research working group named 'The Strength Initiative' which aims to understand and promote strength training across the lifespan.</span></em></p><p class="fine-print"><em><span>Daniel van den Hoek is currently collaborating with the International Paralympic Committee (Para powerlifting) on scientific research projects related to this article. He co-leads a research working group named 'The Strength Initiative' which aims to understand and promote strength training across the lifespan.</span></em></p>Some Paralympic powerlifters lift heavier weights than athletes without disabilities. Here’s what we know about why this might be.Christopher Latella, Lecturer, Master of Exercise Science (Strength and Conditioning), Edith Cowan UniversityDan van den Hoek, Lecturer, Clinical Exercise Physiology, Australian Catholic UniversityLicensed as Creative Commons – attribution, no derivatives.