tag:theconversation.com,2011:/us/topics/cardiovascular-3002/articlesCardiovascular – The Conversation2024-03-15T12:11:36Ztag:theconversation.com,2011:article/2243502024-03-15T12:11:36Z2024-03-15T12:11:36ZPacemaker powered by light eliminates need for batteries and allows the heart to function more naturally − new research<figure><img src="https://images.theconversation.com/files/580746/original/file-20240308-16-3gcx17.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2000%2C1500&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists have designed a solar panel-like pacemaker that can precisely control heartbeats.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/female-silhouett-and-heart-with-pacemaker-royalty-free-image/1490726996">Eugene Mymrin/Moment via Getty Images</a></span></figcaption></figure><p>By harnessing light, my colleagues <a href="https://scholar.google.com.sg/citations?user=hO6bRlwAAAAJ&hl=en">and I</a> designed a wireless, ultrathin pacemaker that operates like a solar panel. This design not only eliminates the need for batteries but also minimizes disruptions to the heart’s natural function by molding to its contours. Our research, recently <a href="https://doi.org/10.1038/s41586-024-07016-9">published in the journal Nature</a>, offers a new approach to treatments that require electrical stimulation, such as heart pacing.</p>
<p><a href="https://theconversation.com/how-do-pacemakers-and-defibrillators-work-a-cardiologist-explains-how-they-interact-with-the-electrical-system-of-the-heart-217429">Pacemakers are medical devices</a> implanted in the body to regulate heart rhythms. They’re composed of electronic circuits with batteries and leads anchored to the heart muscle to stimulate it. However, leads can fail and damage tissue. The location of the leads can’t be changed once they’re implanted, limiting access to different heart regions. Because pacemakers use rigid, metallic electrodes, they may also damage tissue when <a href="https://www.nhlbi.nih.gov/health/heart-surgery/during">restarting the heart after surgery</a> or <a href="https://www.mayoclinic.org/diseases-conditions/heart-arrhythmia/symptoms-causes/syc-20350668">regulating arrhythmia</a>.</p>
<p>Our team envisioned a leadless and more flexible pacemaker that could precisely stimulate multiple areas of the heart. So we designed a device that <a href="https://doi.org/10.1038/s41586-024-07016-9">transforms light into bioelectricity</a>, or heart cell-generated electrical signals. Thinner than a human hair, our pacemaker is made of an optic fiber and silicon membrane that the <a href="https://tianlab.uchicago.edu/">Tian lab</a> and colleagues at the University of Chicago <a href="https://pme.uchicago.edu/">Pritzker School of Molecular Engineering</a> have spent years developing. </p>
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<figcaption><span class="caption">Like solar panels, this pacemaker is powered by light.</span></figcaption>
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<p>Unlike <a href="https://www.energy.gov/eere/solar/solar-photovoltaic-cell-basics">conventional solar cells</a> that are usually designed to collect as much energy as possible, we tweaked our device to generate electricity only at points where light strikes so it can precisely regulate heartbeats. We did this by using a layer of very small pores that can trap light and electrical current. Only cardiac muscles exposed to light-activated pores are stimulated.</p>
<p>Because our device is so small and light, it can be implanted without opening the chest. We were able to <a href="https://doi.org/10.1038/s41586-024-07016-9">successfully implant it</a> in the hearts of rodents and an adult pig, pacing the beats of different heart muscles. Because <a href="https://theconversation.com/organs-from-genetically-engineered-pigs-may-help-shorten-the-transplant-wait-list-175893">pig hearts</a> are anatomically similar to human hearts, this accomplishment shows our device’s potential to translate to people.</p>
<h2>Why it matters</h2>
<p>Heart disease is the <a href="https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death">leading cause of death around the world</a>. Annually, <a href="https://www.nhlbi.nih.gov/health/heart-surgery">over 2 million people</a> undergo open-heart surgery to treat heart problems, including to <a href="https://theconversation.com/how-do-pacemakers-and-defibrillators-work-a-cardiologist-explains-how-they-interact-with-the-electrical-system-of-the-heart-217429">implant devices</a> that regulate heart rhythms and prevent heart attacks.</p>
<p>Our ultralight device gently conforms to the surface of the heart, enabling less invasive stimulation and improved pacing and synchronized contraction. To reduce postoperative trauma and recovery time, our device can be implanted with a minimally invasive technique.</p>
<h2>What still isn’t known</h2>
<p>Currently, our technology is best first used for urgent heart conditions, including restarting the heart after surgery, heart attack and ventricular defibrillation. We continue to explore its long-term effects and durability in the human body.</p>
<p>The body’s internal environment is <a href="https://doi.org/10.1017/jfm.2022.272">rich in fluids</a> that are disturbed by the heart’s constant mechanical motion. This could potentially compromise the device’s functionality over time. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="ECG reading of patient with pacemaker syndrome" src="https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=303&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=303&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=303&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580750/original/file-20240308-28-ptbgx3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&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">Pacemaker syndrome is a condition that develops from stimulating heart muscles in isolation.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:E00031141_(CardioNetworks_ECGpedia).jpg">Michael Rosengarten BEng, MD.McGill/EKG World Encyclopedia via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>Moreover, researchers don’t fully understand how the body reacts to prolonged exposure to medical devices. The formation of <a href="https://theconversation.com/implants-like-pacemakers-and-insulin-pumps-often-fail-because-of-immune-attacks-stopping-them-could-make-medical-devices-safer-and-longer-lasting-211090">scar tissue</a> around the device after implantation can diminish its sensitivity. We are developing special surface treatments and biomaterial coatings to decrease the likelihood of rejection. </p>
<p>Although the breakdown of our device results in a nontoxic substance the body can safely absorb called <a href="https://doi.org/10.1038/s41578-020-0230-0">silicic acid</a>, evaluating how the body responds to extended implantation is essential to ensure safety and effectiveness.</p>
<h2>What’s next</h2>
<p>To achieve long-term implantation and tailor the device to each patient, we are refining the rate at which it dissolves naturally in the body. We are exploring enhancements to make the device compatible as a wearable pacemaker. This involves integrating a wireless light-emitting diode, or LED, beneath the skin that is connected to the device via an optical fiber.</p>
<p>Our ultimate goal is to broaden the scope of what we call photoelectroceuticals beyond cardiac care. This includes <a href="https://theconversation.com/brain-stimulation-can-rewire-and-heal-damaged-neural-connections-but-it-isnt-clear-how-research-suggests-personalization-may-be-key-to-more-effective-therapies-182491">neurostimulation</a>, neuroprostheses and pain management to treat neurodegenerative conditions such as <a href="https://www.parkinson.org/understanding-parkinsons/statistics">Parkinson’s disease</a>. </p>
<p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take on interesting academic work.</em></p><img src="https://counter.theconversation.com/content/224350/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Pengju Li consults to the Pritzker School of Molecular Engineering. He receives funding from the University of Chicago.</span></em></p>Researchers designed an ultrathin pacemaker that can be implanted via minimally invasive techniques, potentially improving recovery time and reducing the risk of complications.Pengju Li, Ph.D. Candidate in Molecular Engineering, University of Chicago Pritzker School of Molecular EngineeringLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2174292023-12-11T13:12:20Z2023-12-11T13:12:20ZHow do pacemakers and defibrillators work? A cardiologist explains how they interact with the electrical system of the heart<figure><img src="https://images.theconversation.com/files/564019/original/file-20231206-17-jlxwsq.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2113%2C1419&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Electrocardiograms, or ECGs, record the electrical activity of your heart. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/heart-rate-monitor-royalty-free-image/523791776">Randy Faris/The Image Bank via Getty Images</a></span></figcaption></figure><p>Your heart’s job is to keep your pulse steady to pump blood throughout your body. Sometimes your heart rate is slower when you’re relaxing, and sometimes it’s faster when you’re exercising or stressed. If your heart’s ability to keep the beat starts to go awry, <a href="https://scholar.google.com/citations?view_op=list_works&hl=en&user=IM1QEMIAAAAJ">cardiac electrophysiologists like me</a> look for outside help from an implantable device.</p>
<p>There are two common implantable devices for the heart: <a href="https://www.nhlbi.nih.gov/health/pacemakers">artificial pacemakers</a> and <a href="https://www.nhlbi.nih.gov/health/defibrillators">defibrillators</a>. Artificial pacemakers keep blood and oxygen flowing during times of stress. Defibrillators are devices that detect dangerously fast heart rates and deliver shocks like those used during cardiopulmonary resuscitation, also known as CPR, to restart the heart.</p>
<p>Understanding how these devices work requires appreciating how the heart’s electrical system works and the weak links that cause malfunctions.</p>
<h2>The heart’s natural pacemaker system</h2>
<p>Abnormally slow heart rates result from breakdowns in two principal areas of the heart. </p>
<p>First, the <a href="https://www.ncbi.nlm.nih.gov/books/NBK459238/">sinoatrial, or SA, node</a> sets your “resting” heart rate, usually somewhere between 60 and 100 beats per minute. This is the base effort needed to circulate enough blood to sustain normal bodily function. Elevated levels of certain hormones circulating in the body, such as adrenaline and serotonin, can <a href="https://doi.org/10.3389/fphys.2020.00170">increase heart rate above resting levels</a>. </p>
<p>Trained athletes frequently have a lower resting heart rate due to extra physical conditioning. Like any other muscle, the heart becomes stronger with training. Because their heart functions more efficiently, athletes <a href="http://dx.doi.org/10.1136/heart.89.12.1455">require fewer heart beats overall</a> to circulate blood. </p>
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<a href="https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of cross-section of heart showing the SA and AV nodes" src="https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=541&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=541&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=541&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=680&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=680&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564020/original/file-20231206-25-3nscgh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=680&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">Breakdowns in the sinoatrial and atrioventricular nodes can cause heart rate problems.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Conduction_system_en_(CardioNetworks_ECGpedia).png">Rob Kreuger, medical illustrator/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.ncbi.nlm.nih.gov/books/NBK557664/">atrioventricular, or AV, node</a> is the second key area of the heart’s electrical wiring. The atrioventricular node takes information about how fast the heart is beating from the sinoatrial node and relays it to the ventricles, the muscular portions of the heart that allow it to pump blood to the rest of the body. </p>
<p>When the atrioventricular node breaks down, the ventricles don’t receive the electrical signal from the sinoatrial node instructing them to “pump,” or create a heartbeat. This causes heart rate to become dangerously slow. </p>
<h2>When heart rate is too slow</h2>
<p>If resting heart rate is abnormally low or fails to increase with hormonal changes, pacemakers can help keep blood and oxygen circulating at a healthy rate. </p>
<p>Both the SA node and the AV node <a href="https://doi.org/10.1146%2Fannurev-physiol-021119-034453">naturally slow with age</a>, but sometimes this happens at an accelerated pace and leads to abnormally slow heart rates. Slow heart rates can also be caused by other diseases, including <a href="https://www.thyroid.org/patient-thyroid-information/ct-for-patients/february-2020/vol-13-issue-2-p-3-4/">thyroid problems</a> and <a href="https://theconversation.com/lyme-carditis-things-can-get-complicated-when-lyme-disease-affects-heart-function-167045">Lyme disease</a>. In these cases, slow rates are treatable without a pacemaker.</p>
<p>A common <a href="https://www.nhlbi.nih.gov/health/pacemakers/how-it-works">pacemaker system</a> has a battery and two wires that can send and receive electrical signals. One wire rests near the sinoatrial node, and the second in one of the heart’s ventricles. </p>
<p>If the wire near the sinoatrial node doesn’t detect any electrical activity over a set time, the pacemaker’s battery will send an impulse to the ventricle to initiate an electrical signal. Within fractions of a second, the wire in the ventricle should detect that electrical activity. If an impulse is detected, this signifies that the AV node conducted the signal correctly to the rest of the heart, and the pacemaker does not activate. If the wire doesn’t receive this signal, the battery delivers an impulse through the wire directly to the ventricle, causing the muscle to contract and initiate a heartbeat.</p>
<p>The heart’s muscle will only contract in response to a pacemaker impulse if the muscle is otherwise healthy. Pacemakers <a href="https://scienceillustrated.com.au/blog/medicine/ask-us-will-pacemakers-still-work-after-death/">do not keep patients alive</a> if the heart shuts down, such as during a massive infection, blood clot or kidney failure. Pacemakers simply keep the heart rate in a comfortable range if the primary problem in the heart is electrical.</p>
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<a href="https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of cross-section of heart with implanted pacemaker" src="https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=505&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=505&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=505&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=635&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=635&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564018/original/file-20231206-34417-smw7n5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=635&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">Pacemaker electrodes are implanted directly in the heart.</span>
<span class="attribution"><a class="source" href="https://www.nhlbi.nih.gov/sites/default/files/inline-images/images_279.jpg">National Heart, Lung, and Blood Institute</a></span>
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<p>Doctors program a pacemaker’s software so the resting pulse doesn’t drop below a certain rate, commonly 50 to 60 beats per minute. If the resting rate is set at 60 beats per minute, the pacemaker will wait exactly one second before initiating an electrical pulse. The heart’s pulse rate can be higher than this number if the sinoatrial node initiates a heartbeat naturally. If the pacemaker detects activity from the sinoatrial node, it will reset its timer for another full second. </p>
<p>Modern pacemakers also contain sensors to predict whether the heart may benefit from a faster heart rate under certain circumstances. For example, pacemaker batteries <a href="https://doi.org/10.1111/jce.14733">contain accelerometers</a> like those used in pedometers to detect if a person is in motion. If these sensors activate, the pacemaker can raise its minimum rate like how the heart would normally respond to exercise. Sensors can also detect if a person begins to breathe more quickly or if the heart begins to contract more powerfully, all signs normally associated with increases in heart rate. </p>
<h2>When heart rate is too fast</h2>
<p>Like pacemakers, a <a href="https://www.nhlbi.nih.gov/health/defibrillators/how-do-defibrillators-work">cardiac defibrillator</a> comes with a battery and wires that record the heart’s rate. But instead of treating slow heart rates, defibrillators are programmed to detect fast heart rates, usually in the range of 200 beats per minute. Heart rates in this range are often caused by <a href="https://www.ncbi.nlm.nih.gov/books/NBK532954/">ventricular tachycardia</a> or <a href="https://www.ncbi.nlm.nih.gov/books/NBK537120/">ventricular fibrillation</a>, which are potentially lethal heart rhythms resulting from the lower chamber of the heart beating too quickly or quivering.</p>
<p>Certain people are at elevated risk for these types of rhythm disturbances. Many <a href="https://doi.org/10.1093/eurheartj/ehad015">cases of “sudden death”</a> in athletes and other young people are either suspected or proved to be related to ventricular fibrillation. </p>
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<iframe src="https://player.vimeo.com/video/721214086" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Defibrillators deliver an electric charge to restart the heart.</span></figcaption>
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<p>Defibrillators deliver internal shocks to the heart when their sensors detect either ventricular tachycardia or ventricular fibrillation. These shocks stop the heart for a fraction of a second to give the sinoatrial node a chance to resume its normal activity. These shocks <a href="https://abcnews.go.com/Health/HeartRhythmTreatment/story?id=5213935#">can be painful</a>, so doctors usually also prescribe medications or other procedures to help prevent needing the shocks in the first place. </p>
<p>A defibrillator is like a seatbelt: It is reassuring to have, but ideally it never needs to be deployed. </p>
<h2>Beyond the surgery</h2>
<p>Pacemakers and defibrillators do require some maintenance. Certain settings, such as how low the pacemaker will allow the pulse to go, <a href="https://doi.org/10.1111/j.1540-8159.2007.00968.x">can be adjusted over time</a>. Doctors have computers that can communicate with the devices and alter their programming. Some devices use Bluetooth technology. </p>
<p>The battery cannot be recharged and must be replaced, generally after six to 10 years. <a href="https://doi.org/10.1093/europace/eun359">Battery life</a> depends on how frequently the heart requires the pacemaker to initiate heartbeats. <a href="https://doi.org/10.5603/KP.2015.0147">Pacemaker wires</a> occasionally need to be replaced if they fracture or if the insulation wears down after years of bending with each heartbeat. On rare occasions, pacemaker parts are recalled. Usually these parts do not require replacement but <a href="https://doi.org/10.1007%2Fs12471-015-0669-6">may require special attention</a>. More frequent checkups of the electrical “health” of the devices are usually prescribed for early detection of any problems with battery life or wire failures.</p>
<p>Pacemakers and defibrillators are always changing, in part to keep up with medical and nonmedical technologies.</p>
<p>With cloud-based management systems that make medical information available to doctors in real time, <a href="https://theconversation.com/three-reasons-why-pacemakers-are-vulnerable-to-hacking-83362">security has become a major focus</a> of modern pacemaker software. Other medical technologies such as MRIs can change how pacemakers and defibrillators work if not handled carefully – MRIs create electromagnetic impulses that cardiac devices <a href="https://doi.org/10.1148/radiol.2018180285">can misinterpret as heartbeats</a>. Modern devices are engineered with these factors in mind, but still require careful programming for these special circumstances.</p>
<p>When used correctly, pacemakers and defibrillators improve both quality of life and life expectancy. While teams of engineers design these small machines, they rely on doctors knowing who will benefit from this technology and how to program the software to best serve each specific patient and scenario.</p><img src="https://counter.theconversation.com/content/217429/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Virginia Singla consults for Medtronic. </span></em></p>Heart rates that are too slow or too fast can sometimes be lethal. Medical implants can help the heart get its rhythm back.Virginia Singla, Clinical Assistant Professor of Cardiology, University of PittsburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2100532023-07-21T02:57:24Z2023-07-21T02:57:24ZGood news for 'weekend warriors’: people who do much of their exercise on a couple of days still get heart benefits<figure><img src="https://images.theconversation.com/files/538651/original/file-20230721-23-vk6bvb.jpg?ixlib=rb-1.1.0&rect=13%2C26%2C4468%2C2896&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/z4WH11FMfIQ">Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Physical activity has <a href="https://bjsm.bmj.com/content/54/24/1451">established benefits</a> for health. The <a href="https://bjsm.bmj.com/content/54/24/1451">World Health Organization</a> recommends adults do a minimum of 150–300 minutes of moderate or 75–150 minutes of vigorous activity each week. This can include active transport from place-to-place, exercise for fun and fitness, energetic housework or physical activity at work. </p>
<p>These amounts can be accrued by being, as the <a href="https://bjsm.bmj.com/content/54/24/1451">WHO recommends</a>, regularly active throughout the week, or being a “weekend warrior” who does the bulk of their activity on one to two days only, which don’t need to be consecutive. </p>
<p>So far, experts haven’t fully established which of the two patterns is better for overall health. For many people, busy lifestyles may make it hard to be physically active every day. It may be more feasible to squeeze most physical activity and exercise into a few days.</p>
<p>Fresh <a href="https://jamanetwork.com/journals/jama/fullarticle/2807286">analysis</a> of the large <a href="https://www.ukbiobank.ac.uk/">UK Biobank</a> database attempted to compare these two patterns of weekly activity and compare how they reduced cardiovascular risk for heart attacks, heart failure, irregular heart beat and stroke.</p>
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Read more:
<a href="https://theconversation.com/short-bursts-of-physical-activity-during-daily-life-may-lower-risk-of-premature-death-new-research-196304">Short bursts of physical activity during daily life may lower risk of premature death – new research</a>
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<h2>What the new study found</h2>
<p>Researchers analysed records from 89,573 participants who wore a wrist activity tracker for seven days and were tracked for cardiovascular events for over six years. </p>
<p>Those who did less than the WHO recommended 150 minutes of moderate-to-vigorous physical activity per week were considered inactive. About a third (33.7%) of participants were inactive. Some 42.2% were termed active “weekend warriors” (they did at least 150 minutes and more than half of it occurred within one to two days) and 24% were regularly active (at least 150 minutes with most activity spread out over three or more days). </p>
<p>Researchers considered the potential factors that could explain the link between physical activity and new cases of cardiovascular events, such as smoking and alcohol intake. They found both active groups showed similarly lower risk of heart attack (a 27% reduction for weekend warriors and 35% for regularly active people, compared with inactive participants). </p>
<p>For heart failure, weekend warriors had a 38% lower risk than inactive people, while regular exercisers had a 36% lower risk. Irregular heartbeat risk was 22% lower for weekend warriors and 19% lower for regularly actively people. Stroke was 21% and 17% lower for weekend warriors and regular exercisers, respectively. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="three women walking along outdoor path together" src="https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=434&fit=crop&dpr=1 600w, https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=434&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=434&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=545&fit=crop&dpr=1 754w, https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=545&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/538653/original/file-20230721-19-57170c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=545&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Busy people might find it easier to plan activity on the weekend.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lovely-group-three-senior-mature-retired-1421249321">Shutterstock</a></span>
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<h2>Not so fast. Some study limitations</h2>
<p>It is surprising the study’s authors define “weekend warrior” as those who do at least half of their activity in one or two days but did not consider the actual days of the week the activity was done. The main study results we describe above refer to doing most exercise in one or two days of the week, not a weekend pattern.</p>
<p>Closer examination of the study’s <a href="https://jamanetwork.com/journals/jama/fullarticle/2807286">supplementary data</a>, where data for Saturday and Sunday are presented, show those who are regularly active, but not those who exercise on the actual weekend, enjoy lower risk of stroke (20%).</p>
<p>Despite the many advantages the UK Biobank activity trackers have over <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2596007">questionnaire-based studies</a>, these trackers are not great at capturing strength-training exercise, such as weights or pilates, and other static activities that have <a href="https://academic.oup.com/aje/article/187/5/1102/4582884">established cardiovascular</a> health benefits.</p>
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<strong>
Read more:
<a href="https://theconversation.com/poor-sleep-is-really-bad-for-your-health-but-we-found-exercise-can-offset-some-of-these-harms-163270">Poor sleep is really bad for your health. But we found exercise can offset some of these harms</a>
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<h2>What other research in this area says</h2>
<p>There have been several questionnaire based studies in this area in <a href="https://academic.oup.com/aje/article/160/7/636/136697">the past 20 years</a>. </p>
<p>Our <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2596007">2017 study</a>, for example, combined data from 63,591 adults from England and Scotland and tracked them over 12 years. We looked at <a href="https://theconversation.com/weekend-warrior-exercise-is-it-good-for-you-70964">risk reductions</a> for death from any cause, cardiovascular disease and cancer causes. We found similar benefits among people who clocked at least 150 minutes of moderate-intensity physical activity or at least 75 minutes of vigorous-intensity physical activity in one to two sessions per week, compared with three sessions or more per week. </p>
<p>Our more <a href="https://www.nature.com/articles/s41591-022-02100-x">recent studies</a> used activity trackers and emphasised the flexibility of activity patterns that benefit the heart and circulation. We found doing short one-minute-long bouts of incidental vigorous physical activity three to four times a day can cut the risk of death from cardiovascular causes by <a href="https://www.nature.com/articles/s41591-022-02100-x">almost half</a>. </p>
<p>Similarly, in another study we found just 19 minutes of vigorous physical activity a week was associated with <a href="https://academic.oup.com/eurheartj/article/43/46/4801/6771381">40% reduction</a> in the risk of cardiovascular death, with steadily increasing benefits to the maximum amount of vigorous activity recorded (110 minutes a week linked to a 75% risk reduction). </p>
<hr>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/aiming-for-10-000-steps-it-turns-out-7-000-could-be-enough-to-cut-your-risk-of-early-death-167447">Aiming for 10,000 steps? It turns out 7,000 could be enough to cut your risk of early death</a>
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<h2>What it means for you and your routine</h2>
<p>Taken together, the <a href="https://jamanetwork.com/journals/jama/fullarticle/2807286">new study</a> and <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2596007">previous research</a> suggest the same thing: if it is difficult or impossible to find time to be active during a busy week, it is good enough to plan moderate to vigorous physical activities in a couple of weekdays or in the weekend.</p>
<p>That said, the study’s supplementary data show a clear advantage in being regularly physically active on most days of the week. This is not surprising considering it has been established that a good session of aerobic exercise, for example, improves heart health risk factors such as <a href="https://www.ahajournals.org/doi/full/10.1161/HYP.0000000000000196">blood pressure</a>, and <a href="https://link.springer.com/article/10.1007/s40279-021-01473-2">blood glucose</a> and <a href="https://lipidworld.biomedcentral.com/articles/10.1186/s12944-017-0515-5">cholesterol levels</a> for a day or longer. Such effects assist with the day-to-day management of these risk factors and provide better long-term protection against major heart and circulatory events.</p>
<p>But confirmation that how physical activity can be accumulated across the week for heart health benefits is relatively flexible is encouraging. It offers more opportunities for more people to be active when it is convenient and practical for them, which is considerably better than being inactive.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/why-exercising-your-good-arm-can-also-help-the-one-in-a-sling-200167">Why exercising your 'good arm' can also help the one in a sling</a>
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<p><em>Correction: this article has been updated to reflect additional information presented in the study’s supplementary material that shows the researchers’ use of “weekend warriors” does not refer to specific days of the week.</em></p><img src="https://counter.theconversation.com/content/210053/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors 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>Too busy to exercise during the week? The good news is that getting moving on the weekend appears to be similarly good for your heart health.Emmanuel Stamatakis, Professor of Physical Activity, Lifestyle, and Population Health, University of SydneyMatthew Ahmadi, Postdoctoral Research Fellow, University of SydneyRaaj Kishore Biswas, Research Fellow & Biostatistician, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1948982022-12-26T20:52:15Z2022-12-26T20:52:15ZHeart rate variability – what to know about this biometric most fitness trackers measure<figure><img src="https://images.theconversation.com/files/500755/original/file-20221213-14408-pvtw3d.jpg?ixlib=rb-1.1.0&rect=1047%2C901%2C6039%2C3884&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An increase in this particular biometric is a good thing.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/senior-man-using-smartwatch-in-bed-royalty-free-image/1371086366">visualspace/E+ via Getty Images</a></span></figcaption></figure><p>Your heart beats <a href="https://www.pbs.org/wgbh/nova/heart/heartfacts.html">around 100,000 times every day</a>. <a href="https://theconversation.com/tracking-your-heart-rate-5-questions-answered-about-what-that-number-really-means-124066">Heart rate</a> is a key marker of cardiovascular activity and an important vital sign. But your pulse is not as steady as a precision clock – nor would you want it to be.</p>
<p><a href="https://scholar.google.com/citations?hl=en&user=uXcM0scAAAAJ">As a cardiovascular physiologist</a>, I measure heart rate in nearly every experiment my students and I perform. Sometimes we use an <a href="https://medlineplus.gov/lab-tests/electrocardiogram/">electrocardiogram</a>, such as you’d see in a medical clinic, which uses sticky electrodes to measure electrical signals between two points of your body. Other times we use a chest strap monitor, like ones you might see on someone at the gym, which also detects heartbeats based on electrical activity.</p>
<p>As wearable technology has grown more popular, it’s not just researchers and cardiologists who are paying attention to heart rate. You might be monitoring your own all day long via a fitness tracker you wear on your wrist. This kind of wearable device <a href="https://help.fitbit.com/articles/en_US/Help_article/1565.htm">uses green light to detect blood flow</a> beneath your skin and deduces your heart rate.</p>
<p>Here are what heart rate and other measurements derived from this biometric can tell you about your body’s health.</p>
<h2>Pumping blood where it needs to go</h2>
<p>The heart’s primary job is to contract and generate pressure that helps pump blood to the lungs to be oxygenated and then on to the rest of the body to deliver oxygen and other nutrients. Heart rate is simply how fast your heart is beating. Sometimes called a pulse rate, it’s normally presented in beats per minute. You can <a href="https://www.health.harvard.edu/heart-health/want-to-check-your-heart-rate-heres-how">count your own heart rate</a> by feeling for your pulse inside your wrist or behind your jaw. </p>
<p>When your body demands more oxygen, such as during exercise, heart rate will increase along with the increasing workloads.</p>
<p>While many people are familiar with tracking their heart rate during exertion, the heart rate at rest can also provide valuable information. The two parts of the <a href="https://www.webmd.com/heart/what-is-heart-rate-variability">autonomic nervous system</a>, the sympathetic and parasympathetic, influence resting heart rate. The sympathetic branch helps coordinate your body’s stress response. The more active it is, the higher it dials up your heart rate, preparing you for fight or flight. </p>
<p>The parasympathetic branch of your nervous system is responsible for keeping lots of your body’s functions running smoothly while you’re at ease. Via the vagus nerve that runs from the brain all the way to the abdomen, the parasympathetic nervous system actively slows the heart down to resting values between <a href="https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/all-about-heart-rate-pulse">60 and 100 beats</a> per minute for the average healthy adult. Without any parasympathetic activity putting the brakes on the sympathetic nervous system’s signals, your heart would beat at approximately 100 beats per minute. </p>
<p>A lower resting heart rate indicates an efficient heart and a higher level of parasympathetic activity. When you’re at rest your nervous system is ideally minimizing sympathetic activity, so you’re conserving energy and avoiding unnecessary stress to the body.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="chart of red peaks of a heartbeat at slightly different intervals" src="https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=274&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=274&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=274&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=344&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=344&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500523/original/file-20221212-119183-4pofku.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=344&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 chart of a heart rate reveals tiny differences in spacing between the peaks representing heartbeats.</span>
<span class="attribution"><span class="source">YitzhakNat via Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Time between each heartbeat</h2>
<p>One specific way to understand the balance of the nervous system’s influence on heart rate is to look at <a href="https://my.clevelandclinic.org/health/symptoms/21773-heart-rate-variability-hrv#:%7E:text=Heart%20rate%20variability%20is%20where,issues%20like%20anxiety%20and%20depression.">heart rate variability</a>, or HRV – the slight fluctuation in the time between each heartbeat. Even if your heart rate is 60 beats a minute, that doesn’t mean your heart is pumping exactly once every second.</p>
<p>Less variability is a sign that your body is under greater stress and that the balance in your autonomic nervous system is tipping toward the sympathetic branch being in charge. Greater variability suggests you’re more relaxed and your parasympathetic nervous system is in control. </p>
<p>For nearly 30 years, scientists have been interested in <a href="https://doi.org/10.1161/01.CIR.93.5.1043">how to measure and interpret HRV</a>, specifically as it relates to this balance of autonomic control.</p>
<p>The clinical utility of HRV emerged in patients following cardiac events, but researchers are now considering how this measure can help explain patient outcomes in a range of <a href="https://doi.org/10.2147/VHRM.S279322">cardiac</a>, <a href="https://doi.org/10.1371/journal.pone.0195166">endocrine</a> and <a href="https://doi.org/10.1016/j.jad.2018.04.071">psychiatric</a> disorders.</p>
<p>More recently, researchers have investigated <a href="https://doi.org/10.15420/aer.2018.27.2">how to use HRV</a> in <a href="https://doi.org/10.15420/aer.2018.30.2">athletic training and prognosis of medical conditions</a>.</p>
<p>Several fitness wearables also report <a href="https://support.whoop.com/WHOOP_Data/Recovery__HRV/What_is_Heart_Rate_Variability_(HRV)%3F">heart rate variability</a>, either as a <a href="https://support.ouraring.com/hc/en-us/articles/360025441974-An-Introduction-to-Heart-Rate-Variability#:%7E:text=How%20Oura%20Measures%20HRV,samples%20measured%20while%20you%20sleep.">stand-alone metric</a> or used in the calculation of “readiness” or “recovery” scores. <a href="https://doi.org/10.1055/a-1864-9726">Endurance athletes now commonly track HRV</a> as one way to monitor their overall physiological state.</p>
<p>Researchers have started checking which <a href="https://doi.org/10.3390/s22166317">commercially available wearable devices are most reliable and accurate</a> at measuring HRV, which can vary from tracker to tracker. Many of these devices use colored lights, or optical sensors, to measure pulse rate and other variables at the wrist or finger. Unfortunately, the <a href="https://www.statnews.com/2019/07/24/fitbit-accuracy-dark-skin/">accuracy of this method can vary based on skin type and skin color</a>. It is important that companies include diverse populations in the design, testing and validation of these products to help address potential racial health disparities.</p>
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<a href="https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman doing standing pose on yoga mat" src="https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500758/original/file-20221213-19390-g5huck.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">Another health benefit of stress-busting activities can be an increase in heart rate variability.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-standing-on-yoga-mat-in-warrior-pose-while-royalty-free-image/1397801043">David Espejo/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>Nudging HRV in a good direction</h2>
<p>One of the biggest influences on heart rate variability is stress; along with increased sympathetic nervous system activity, stress is associated with lower HRV. Stress-reducing interventions, <a href="https://my.clevelandclinic.org/health/treatments/13354-biofeedback">biofeedback</a> and <a href="https://doi.org/10.1016/s0828-282x(10)70395-0">increased fitness</a> can increase heart rate variability. Remember, an increase is good for this metric. Overall, <a href="https://www.webmd.com/heart/what-is-heart-rate-variability#091e9c5e82171840-2-4">heart rate variability depends on</a> a range of physiological, psychological, environmental, lifestyle and nonmodifiable genetic <a href="https://doi.org/10.3389/fpubh.2017.00258">factors</a>.</p>
<p>The most useful way to consider heart rate variability as a metric is to look at data trends. Are there consistent changes in HRV in either direction? Examine these changes alongside other health factors such as fitness, mood, illness, sleep and dietary intake to see if you can draw any conclusions about lifestyle modifications you may want to make.</p>
<p>In general, the <a href="https://www.va.gov/WHOLEHEALTHLIBRARY/tools/heart-rate-variability-and-arrhythmias.asp">same approaches</a> you would take to lowering resting heart rate can also improve heart rate variability, such as increasing cardiovascular fitness, maintaining a healthy weight, reducing stress and getting sufficient sleep.</p>
<p>It’s important to remember that heart rate variability is the normal, healthy, very slight fluctuation of timing of heartbeats – just milliseconds of difference from beat to beat. More dramatic changes in heart rhythms or the way in which the heart contracts, known as <a href="https://www.mayoclinic.org/diseases-conditions/heart-arrhythmia/symptoms-causes/syc-20350668">arrhythmias</a>, may signal a more serious condition that requires medical attention.</p><img src="https://counter.theconversation.com/content/194898/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anne R. Crecelius 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>Tiny fluctuations in the time between each beat of your heart can provide clues about how much stress your body is experiencing.Anne R. Crecelius, Associate Professor of Health and Sport Science, University of DaytonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1854902022-06-22T23:23:57Z2022-06-22T23:23:57ZWomen are at greater risk of stroke, the more miscarriages or stillbirths they’ve had<figure><img src="https://images.theconversation.com/files/470180/original/file-20220622-3417-j39jvf.jpg?ixlib=rb-1.1.0&rect=44%2C44%2C5910%2C3916&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/pelvic-screening-ultrasound-pregnancy-10-600w-1704463945.jpg">Shutterstock</a></span></figcaption></figure><p>New <a href="https://www.bmj.com/content/377/bmj-2022-070603">research</a> shows women who have had a miscarriage or stillbirth, have an increased risk of <a href="https://strokefoundation.org.au/about-stroke/learn/what-is-a-stroke">stroke</a> – when blood can’t get to the brain, because of a blocked or burst artery. That risk increases with each miscarriage or stillbirth.</p>
<p>Trying to establish this link is difficult because it requires following a large number of women over a long period of time and having reliable data on women’s experiences. Our study, published by the British Medical Journal today, is the first to conclusively show the link between pregnancy loss and stroke. </p>
<p>Many women are unaware their experiences during pregnancy can be an early marker of later health dangers. Our findings show their doctors should be alert to their increased risk. </p>
<p>It’s possible infertility, miscarriage, and stillbirth could increase stroke risk because of other health issues. These could include endocrine disorders (low oestrogen or insulin resistance), inflammation, problems with endothelial cells that assist in blood flow, psychological disorders, unhealthy behaviours (such as smoking) or obesity.</p>
<h2>Heartbreak then stroke risk</h2>
<p>Our <a href="https://www.bmj.com/content/377/bmj-2022-070603">research</a> is based on pooled data from 618,851 women who took part in eight separate studies in Australia, China, Japan, Netherlands, Sweden, the United Kingdom and the United States. </p>
<p>The women were aged between 32 and 73 when they were first enrolled in the studies and were followed up for an average of 11 years.</p>
<p>The study showed that over the time they were studied, 9,265 (2.8%) women had at least one non-fatal stroke and 4,003 (0.7%) women had a fatal stroke. Overall, 91,569 (16.2%) women had a history of miscarriage while 24,873 (4.6%) had a history of stillbirth.</p>
<p>Among the women who had ever been pregnant, women who had reported a miscarriage had a 11% higher risk of a non-fatal stroke and 17% higher risk of a fatal stroke compared with women who have not had a miscarriage. </p>
<p>The risk increased with each miscarriage, so that women who had three or more miscarriages had a 35% higher risk for non-fatal stroke (from incidence rate of 43 per 100,000 “<a href="https://sph.unc.edu/wp-content/uploads/sites/112/2015/07/nciph_ERIC4.pdf">person years</a>” to 58 per 100,000) and an 82% higher risk in fatal strokes (from 11.3 per 100,000 person years to 18 per 100,000) compared with women who had never miscarried. </p>
<p>Stillbirth also significantly increased the risk of stroke. </p>
<p>Among women who had ever been pregnant, women who had a history of stillbirth had a 31% higher risk of non-fatal strokes (from an incidence rate of 42 per 100,000 person years to 69.5 per 100,000) and a 7% higher risk of fatal strokes.</p>
<p>Again, the greater the number of stillbirths, the higher the risk of later strokes, with women who had had two or more stillbirths having a 26% higher risk of fatal strokes (rising from 11 per 100,000 person years to 51.1 per 100,000).</p>
<p>The study is the first to show links with stroke subtypes: stillbirths were linked to non-fatal ischaemic (blockage) stroke or fatal haemorrhagic (bleeding) stroke; miscarriages were linked to both subtypes.</p>
<p>Our study strengthens findings from a previous <a href="https://www.ahajournals.org/doi/full/10.1161/STROKEAHA.121.036271?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org">systematic review</a> that found similar results but showed limited evidence linked to stroke subtypes. </p>
<p>Of the possible explanations for these links, <a href="https://academic.oup.com/humupd/article/18/4/436/664974">problems</a> with endothelial cells (which control vascular relaxation and contraction as well as release blood-clotting enzymes) might lead to pregnancy loss through problems with the placenta. These problems also relate to how blood vessels dilate and get inflamed or blocked <a href="https://www.ahajournals.org/doi/10.1161/STROKEAHA.120.032711#:%7E:text=The%20endothelium%20has%20a%20pivotal,thrombovascular%20complications%20in%20the%20brain.">during stroke</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="dice showing F. A. S. T." src="https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=410&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=410&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470181/original/file-20220622-23-rm7mnk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=410&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Warning signs of a stroke include sudden changes to a person’s face, arm sensations or speech.</span>
<span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/acronym-fast-used-mnemonic-help-600w-1441304957.jpg">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-causes-miscarriages-a-doctor-explains-why-women-shouldnt-blame-themselves-159894">What causes miscarriages? A doctor explains why women shouldn't blame themselves</a>
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</em>
</p>
<hr>
<h2>Adjusting for known risk factors</h2>
<p>Our findings were adjusted for many of the known risk factors for stroke: body mass index, whether the women smoked or not, whether they had high blood pressure, or diabetes. The numbers were also adjusted for ethnicity and education level. </p>
<p>By adjusting for risk factors, we can isolate the increased risk likely linked to the number of miscarriages or stillbirths the women. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/remind-me-again-why-is-salt-bad-for-you-179768">Remind me again, why is salt bad for you?</a>
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</em>
</p>
<hr>
<h2>What should women and their doctors do with this information?</h2>
<p>When doctors do a <a href="https://www.heartfoundation.org.au/heart-health-education/heart-health-checks">heart health check</a>, they look at the risk of <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/heart-disease-and-stroke">cardiovascular disease</a> overall – that is, heart disease, heart failure and stroke. By considering these risks, doctors assess and predict the risk of future disease. </p>
<p>The current Australian <a href="https://informme.org.au/guidelines/guidelines-for-the-management-of-absolute-cvd-risk-2012">guidelines</a> recommend heart health checks should be conducted regularly for people aged 45 to 74, or for Aboriginal and Torres Strait Islander peoples from the age of 30 – this is when the risk of cardiovascular disease starts to increase. </p>
<p>The guidelines recommend medication (blood pressure medication and/or lipid-lowering medication such as statins) when the risk of cardiovascular disease is greater than 15% in the next five years. </p>
<p>These guidelines are currently being updated by the <a href="https://www.acdpa.org.au/">Australian Chronic Disease Prevention Alliance</a> (which includes the Cancer Council Australia, Diabetes Australia, Kidney Health Australia, National Heart Foundation of Australia and the Stroke Foundation), but more recent international guidelines recommend medication at lower levels of risk. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="doctor checks patient's heartbeat" src="https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/470182/original/file-20220622-11-128k56.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">Doctors should be aware and consider women’s pregnancy history in assessing stroke risk.</span>
<span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/close-female-doctor-using-stethoscope-600w-2076573445.jpg">Shutterstock</a></span>
</figcaption>
</figure>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/im-approaching-a-milestone-birthday-what-health-checks-should-i-have-at-my-age-172047">I'm approaching a 'milestone' birthday. What health checks should I have at my age?</a>
</strong>
</em>
</p>
<hr>
<p>No matter what your risk of cardiovascular disease is, the best way to prevent having a stroke is by living as healthy a lifestyle as possible: stopping smoking, eating a healthy diet, having a moderate alcohol intake and doing regular exercise. </p>
<p>These lifestyle measures lower risk for everybody, but doctors will try particularly hard to help people do this who are at long term risk. </p>
<p>Our research shows miscarriage and stillbirth are signals a woman is at increased risk of cardiovascular disease. These events occur many years before a woman develops other risk factors, such as high blood pressure, diabetes or high cholesterol. </p>
<p>Women who have experienced a miscarriage or stillbirth should discuss these with their doctor. Knowing you have a higher risk of stroke is opportunity to monitor your health and make lifestyle changes that can help prevent stroke. </p>
<p>GPs need to ask about women’s reproductive histories and be aware of recurrent miscarriage and stillbirths as potential predictors of stroke risk.</p><img src="https://counter.theconversation.com/content/185490/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gita Mishra receives funding from National Health and Medical Research Council and the Australian Government Department of Health. </span></em></p><p class="fine-print"><em><span>Jenny Doust receives funding from the National Health and Medical Research Council and the Medical Research Futures Fund. She is a member of the National Heart Foundation Clinical Committee. </span></em></p><p class="fine-print"><em><span>Chen Liang 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>Our study is the first to conclusively show the link between pregnancy loss and stroke risk.Gita Mishra, Professor of Life Course Epidemiology, Faculty of Medicine, The University of QueenslandChen Liang, PhD student, The University of QueenslandJenny Doust, Clinical Professorial Research Fellow, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1654462021-08-12T20:03:00Z2021-08-12T20:03:00ZHow COVID affects the heart, according to a cardiologist<figure><img src="https://images.theconversation.com/files/415607/original/file-20210811-17-1owq1qz.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C998%2C435&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>As the pandemic has progressed, researchers have begun to understand how COVID-19 impacts our bodies.</p>
<p>Early in the pandemic, risk factors such as heart disease, high blood pressure and diabetes were <a href="https://www.ijidonline.com/article/S1201-9712(20)30136-3/fulltext">quickly associated</a> with an increased risk of <a href="https://jamanetwork.com/journals/jama/fullarticle/2762130">severe illness and death</a> from COVID.</p>
<p>We now know that, among the myriad ways it can damage our health, the virus can affect the heart and directly cause a range of <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013879/full">heart complications</a>.</p>
<p>Also, mRNA COVID vaccines like those from Pfizer and Moderna have been linked with heart inflammation. But this is very rare, and you’re much more likely to get heart inflammation from COVID infection than the vaccines.</p>
<p>Here’s what we know so far.</p>
<h2>How does COVID affect the heart?</h2>
<p>The SARS-CoV-2 virus can directly invade the body causing inflammation. This can impact the heart, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199677/">causing myocarditis and pericarditis</a> — inflammation of the heart muscle or outer lining of the heart. </p>
<p>Inflammation from COVID <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013879/full">can also cause</a> blood clotting, which can block a heart or brain artery causing a heart attack or stroke.</p>
<p>COVID can also cause abnormal heart rhythms, blood clots in the legs and lungs, and heart failure. Our understanding of how COVID causes <a href="https://www.jacc.org/doi/abs/10.1016/j.jacc.2020.08.059">heart inflammation and injury to the heart muscle</a> is becoming clearer, though there’s more to learn.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1422544670719025156"}"></div></p>
<p>Persistent symptoms from the virus, called “<a href="https://theconversation.com/the-mystery-of-long-covid-up-to-1-in-3-people-who-catch-the-virus-suffer-for-months-heres-what-we-know-so-far-161174">long COVID</a>”, have been reported in about 10-30% of people who’ve contracted COVID.</p>
<p><a href="https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00299-6/fulltext">One study</a> on long COVID, published in July, found common cardiovascular symptoms include heart palpitations, fast heart rate, slow heart rate, chest pain, visible bulging veins, and fainting.</p>
<p>Of roughly 3,700 study participants, over 90% reported their recovery lasted more than eight months.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-mystery-of-long-covid-up-to-1-in-3-people-who-catch-the-virus-suffer-for-months-heres-what-we-know-so-far-161174">The mystery of 'long COVID': up to 1 in 3 people who catch the virus suffer for months. Here's what we know so far</a>
</strong>
</em>
</p>
<hr>
<p>The Delta variant, first identified in India in October 2020, is <a href="https://apps.who.int/iris/bitstream/handle/10665/341622/CoV-weekly-sitrep1Jun21-eng.pdf?sequence=1&isAllowed=y">highly transmissible</a>. It’s the variant responsible for lockdowns in New South Wales, Victoria and Queensland. </p>
<p>Although data is still emerging, it may cause more severe disease, and <a href="https://www.abc.net.au/news/2021-08-07/delta-variant-of-covid-19-causing-heart-problems-young-people/100352868">anecdotally may increase the chances of heart complications</a>.</p>
<p>A <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01358-1/fulltext#sec1">Scottish study</a> found the risk of hospital admission from COVID was around double in those with Delta variant compared to the Alpha variant (which originated in the UK). It also found Delta was spreading most commonly in younger people.</p>
<p>The good news is two doses of either the Pfizer or AstraZeneca vaccines <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2108891">remains effective</a> in preventing Delta complications.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1423941243227099138"}"></div></p>
<h2>COVID vaccines and the heart</h2>
<p>Scientists have discovered a link between the Oxford-AstraZeneca vaccine and <a href="https://theconversation.com/what-is-thrombocytopenia-the-rare-blood-condition-possibly-linked-to-the-astrazeneca-vaccine-158522">a rare blood clotting syndrome</a>.</p>
<p>There’s also a link between mRNA COVID vaccines and a rare side effect of <a href="https://jamanetwork.com/journals/jamacardiology/fullarticle/2781602">heart inflammation</a> (myocarditis and pericarditis). This seems to be most common in males under 30 and after the second vaccine dose. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-benefits-of-a-covid-vaccine-far-outweigh-the-small-risk-of-treatable-heart-inflammation-163970">The benefits of a COVID vaccine far outweigh the small risk of treatable heart inflammation</a>
</strong>
</em>
</p>
<hr>
<p>But this is very rare. Of the <a href="https://www.tga.gov.au/periodic/covid-19-vaccine-weekly-safety-report-05-08-2021">5.6 million Pfizer vaccine doses</a> administered to Australians so far, there have only been <a href="https://www.tga.gov.au/periodic/covid-19-vaccine-weekly-safety-report-05-08-2021">111 cases</a> of suspected (not confirmed) heart inflammation reported up to August 1. There have been no reported deaths associated with this vaccine side effect in Australia. </p>
<p>Recovery from this heart inflammation is generally good. The benefits of vaccination against COVID far outweigh the potential risks of these generally mild conditions. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1423944616127209472"}"></div></p>
<p>Nevertheless, if you experience any change in symptoms after having a COVID vaccine, including chest pain, an irregular heartbeat, fainting or shortness of breath, you should seek prompt medical attention.</p>
<p>The vast majority of people with heart conditions are safe to get vaccinated. But if you have had myocarditis or pericarditis in the past six months then speak with your doctor or cardiologist.</p>
<h2>Don’t delay getting your heart checked</h2>
<p>Many people have been reluctant to seek medical attention amid the pandemic. This includes for both urgent and routine care of heart disease. Longer delays between the onset of the symptoms and hospital treatment <a href="https://academic.oup.com/eurjpc/advance-article/doi/10.1093/eurjpc/zwaa155/6145858">are being reported</a> in countries including England, Italy and China. This makes long-term heart damage more likely. </p>
<p><a href="https://academic.oup.com/ehjqcco/article/7/1/18/5956768">One study</a> found global hospital admissions for heart attacks have decreased between 40% and 50%. <a href="https://www.heartlungcirc.org/article/S1443-9506(21)01041-6/fulltext">An Australian study</a> found a 21% reduction in cardiac surgery at Sydney’s Royal Prince Alfred Hospital between March and June 2020.</p>
<p>It’s important you don’t neglect your heart health even amid the pandemic. If you ever think you’re <a href="https://www.heartfoundation.org.au/conditions/heart-attack">having a heart attack</a>, call triple zero (000) immediately.</p>
<hr>
<p><em>The author would like to thank the National Heart Foundation’s Amanda Buttery and Brooke Atkins for their help with this article.</em></p><img src="https://counter.theconversation.com/content/165446/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Garry Jennings receives funding from the National Health and Medical Research Council. He is Chief Medical Advisor for the Heart Foundation and Interim CEO. He has part time positions with the Baker Heart and Diabetes Institute and Sydney Health Partners, and is Honorary Professor of Medicine at the University of Sydney and Monash University.</span></em></p>COVID can cause heart inflammation, abnormal heart rhythms, blood clots in the legs and lungs, stroke, and heart failure.Garry Jennings, Professor of Medicine, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1646882021-07-21T12:26:07Z2021-07-21T12:26:07ZHeat stroke is a danger, but cardiovascular stress causes more heat wave deaths<figure><img src="https://images.theconversation.com/files/411997/original/file-20210719-15-rxda7x.JPG?ixlib=rb-1.1.0&rect=101%2C173%2C3676%2C2071&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Salvation Army emergency vehicle is set up as a cooling station during a heatwave in Calgary, Alta. on June 30. </span> <span class="attribution"><span class="source">THE CANADIAN PRESS/Jeff McIntosh</span></span></figcaption></figure><p>Every summer we invariably deal with at least one heat wave. With global warming, they are becoming <a href="https://climateatlas.ca/map/canada/hwnum_2030_45#z=4&lat=48.84&lng=-90.26">longer, more intense and more frequent</a>. Heat waves are now among the most dangerous global natural hazards we face, accounting for more fatalities on average than any other extreme weather event, according to the <a href="https://www.weather.gov/hazstat/">United States National Weather Service</a>. </p>
<p>Canada is not immune, as evidenced by the recent heat wave across the Pacific Northwest that included a <a href="https://www.cbc.ca/news/canada/british-columbia/bc-alberta-heat-wave-heat-dome-temperature-records-1.6084203">Canadian record-breaking temperature of nearly 50 C</a> in Lytton, B.C. near the end of June. During the week of the heat wave, the province had <a href="https://www2.gov.bc.ca/assets/gov/birth-adoption-death-marriage-and-divorce/deaths/coroners-service/news/bccs-chief-coroner-updated-statement2.pdf">tripled the number of reported deaths</a> that normally occur during that period. </p>
<p>While the sharp rise in mortality rate during a heat wave is apparent, the cause of those deaths may not always be. Heat stroke is not the only issue. The biggest factor is the stress that extreme heat places on the cardiovascular system (the heart and blood vessels).</p>
<h2>Heat stroke</h2>
<p>Heat stroke, perhaps the most obvious consequence of a heat wave, is the progression of <a href="https://www.mayoclinic.org/diseases-conditions/heat-exhaustion/symptoms-causes/syc-20373250">heat exhaustion</a>, a milder condition that causes symptoms such as heavy sweating, clammy skin, fatigue, feeling faint or dizzy, nausea and headache. </p>
<p><a href="http://doi.org/10.1056/NEJMra1810762">Heat stroke</a> is serious and can be life-threatening. It is subclassified as either classic (occurring when someone is at rest) or exertional (occurring through strenuous physical activity). Both forms result in a series of reactions that cause excessive inflammation, leading to central nervous system dysfunction (confusion, seizures or loss of consciousness) and multiple organ failure.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man walking on a park path with the Calgary skyline in the distance, with a haze of smoke" src="https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412000/original/file-20210719-19-a0839w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Following the western heat wave, a haze of wildfire smoke from British Columbia hangs over downtown Calgary in July 2021.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Jeff McIntosh</span></span>
</figcaption>
</figure>
<p>In classic heat stroke, it is poor heat-dissipating mechanisms or simply excessive heat exposure that is the culprit. With exertional heat stroke, it is the excessive metabolic heat during exercise that exceeds the body’s ability to maintain its temperature through heat-loss mechanisms like sweating. The common characteristic of both forms is a core temperature exceeding 40.5C (normal is 37C). </p>
<p>While heat stroke during a heat wave is certainly a risk, it alone provides a narrow scope of the true health impact. Most often, excess mortality during a heat wave is actually a result of increased cardiovascular burden and amplification of existing health conditions.</p>
<h2>Cardiovascular burden of heat</h2>
<p>When core and skin temperature rise, thermosensors across the body respond by shunting a large proportion of blood to the periphery (skin). This has two primary effects: </p>
<ol>
<li>It increases the skin blood flow allowing an increased sweat rate, and in turn, heat loss via evaporation.</li>
<li>It increases the skin temperature to enable more heat transfer from the body to the environment (heat loss primarily via convection).</li>
</ol>
<p>This process of increasing blood flow to the skin to regulate body temperature (thermoregulation) is taxing on the cardiovascular system. The blood vessels near the skin need to dilate, and the heart needs to pump harder and faster. </p>
<p>That is where the major problem lies: A large fraction of the population has some form of cardiovascular disease. Nearly 10 per cent of Canadian adults suffer from <a href="https://www.canada.ca/en/public-health/services/publications/diseases-conditions/report-heart-disease-Canada-2018.html">heart disease</a>, and nearly two-thirds of Canadians are prone to impaired heart and metabolic function <a href="https://www150.statcan.gc.ca/n1/pub/82-625-x/2019001/article/00005-eng.htm">by being overweight</a>. Not surprisingly, <a href="https://dx.doi.org/10.1249%2FMSS.0000000000000325">rates of cardiovascular events are notably increased</a> during a heat wave.</p>
<h2>Populations at risk</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A boy running through a fountain" src="https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/411998/original/file-20210719-15-1n6mvpx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Children are at risk for heat stroke because of their small size and immature thermoregulation system.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Jeff McIntosh</span></span>
</figcaption>
</figure>
<p>Invariably those who cannot escape the heat, namely outdoor workers and those with poor access to air-conditioning, are most at risk. Young children are also at risk because of their small body size and underdeveloped thermoregulatory system. However, advanced aging and cadiovascular disease is proving to be the biggest factor.</p>
<ul>
<li><p><strong>The elderly</strong>: Advanced aging is associated with a reduced capacity to thermoregulate, primarily attributable to a progressively compromised cardiovascular system. Interestingly, <a href="https://dx.doi.org/10.1080%2F23328940.2017.1379585">behavioral thermoregulation</a> — which includes actions like seeking shade or air conditioning — is also compromised in the elderly, such that cooling strategies are sought out less frequently compared to young adults.</p></li>
<li><p><strong>Disease</strong>: Pre-existing conditions — particularly those involving the cardiovascular system, such as heart disease and diabetes — dramatically increase the risk of heat-related illness. Often, <a href="https://doi.org/10.1111/jcpt.12294">many medications</a> used to treat these diseases can further interfere with the thermoregulatory responses to heat (for example, beta-blockers used to treat high blood pressure can inhibit the heart rate response, and diuretics can exacerbate dehydration).</p></li>
</ul>
<h2>Reducing the risk</h2>
<figure class="align-center ">
<img alt="A sign for an emergency cooling centre in Toronto" src="https://images.theconversation.com/files/411999/original/file-20210719-23-1qqvyj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/411999/original/file-20210719-23-1qqvyj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/411999/original/file-20210719-23-1qqvyj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/411999/original/file-20210719-23-1qqvyj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/411999/original/file-20210719-23-1qqvyj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/411999/original/file-20210719-23-1qqvyj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/411999/original/file-20210719-23-1qqvyj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Seeking relief from the heat is one way to help prevent heat stroke.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Frank Gunn</span></span>
</figcaption>
</figure>
<p>The primary prevention of heat illness is through immediate behaviour. Seeking air-conditioned environments, <a href="https://doi.org/10.1016/j.apergo.2014.07.013">increasing air flow through electric fans</a>, wearing light, breathable and loose-fitting clothing, keeping hydrated and avoiding strenuous activities (especially in the sun) should be the first line of defence, particularly in vulnerable populations. </p>
<p>However, assuring that the cardiovascular system is ready to take on the heat will be an integral step in curtailing the rates of heat illness. If daily exercise is not an option (or too difficult), an alternative may be to safely fight fire with fire — that is, through <a href="https://doi.org/10.1152/japplphysiol.00141.2020">heat therapy</a>. </p>
<p>Supervised heat therapy is emerging as a therapeutic tool for cardiovascular disease by improving heart and blood vessel function. It may also lead to moderate <a href="https://doi.org/10.1111/sms.12408">heat acclimation</a>, which can make it easier to deal with the heat by improving the body’s thermoregulatory response system. </p>
<p>In the end, exercise, a healthy diet, and perhaps also heat therapy (if done safely) will not only reduce the incidence for the leading cause of death worldwide (heart disease), it will also reduce the excess deaths during a heat wave. </p>
<p>Indeed, excess mortality during a heat wave is only marginally explained by incidences of outright heat stroke. Most often it is secondary from the increased cardiovascular burden associated with thermoregulatory responses to the heat.</p><img src="https://counter.theconversation.com/content/164688/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anthony Bain 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 stroke is a danger in extreme temperatures, but a major risk factor for dying during a heat wave is cardiovascular disease and other pre-existing health conditions.Anthony Bain, Assistant Professor, Kinesiology, University of WindsorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1246582019-10-08T13:07:47Z2019-10-08T13:07:47ZWhat is a healthy blood pressure?<figure><img src="https://images.theconversation.com/files/295430/original/file-20191003-52826-1lu3ohy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Taking a reading.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-african-woman-checking-blood-pressure-342229403?src=yYM8_oEZtarKX2tc3-sJuw-1-59">Andrey_Popov/Shutterstock</a></span></figcaption></figure><p>More than 7m people in the UK have <a href="https://www.bhf.org.uk/informationsupport/risk-factors/high-blood-pressure">high blood pressure</a>; it is a leading cause of cardiovascular disease and cardiovascular events such as heart attacks and strokes, associated with one in four deaths. As many as <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/612309/HypertensionprevalenceestimatesinEnglandestimate.pdf">5.6m people in the UK</a> do not realise they have it as they feel fine, while others show signs such as shortness of breath, persistent headaches, blurred vision or nosebleeds. So, what is blood pressure and why is it so important? </p>
<p>Your heart is a pump, roughly the size of your fist. Contraction of the heart muscle generates a force, causing pressure to rise in your blood vessels, which drives the flow of blood around your body. This flow works continually to supply oxygen and nutrients to organs through your arteries and removes waste products through your veins too. The problems begin when the pressure becomes so high that it begins to cause damage to the blood vessels and increase the workload on the heart.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/295428/original/file-20191003-52816-f5y15t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/295428/original/file-20191003-52816-f5y15t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/295428/original/file-20191003-52816-f5y15t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/295428/original/file-20191003-52816-f5y15t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/295428/original/file-20191003-52816-f5y15t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/295428/original/file-20191003-52816-f5y15t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/295428/original/file-20191003-52816-f5y15t.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 blood pressure guage.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blood-pressure-gauge-show-hypertension-high-601073303?src=yYM8_oEZtarKX2tc3-sJuw-1-5">Voraorn Ratanakorn/Shutterstock</a></span>
</figcaption>
</figure>
<p>To measure your blood pressure a cuff is wrapped around your upper arm and connected to an automatic device, but your doctor may prefer to use a stethoscope and <a href="https://www.medicinenet.com/script/main/art.asp?articlekey=15771">sphygmomanometer</a>. A normal blood pressure in the UK is around 120/70<a href="https://www.merriam-webster.com/medical/mm%20Hg">mmHg</a>, measured in millimetres of mercury. The highest number is the systolic pressure, when your heart contracts to push blood through your arteries. The lower number is the diastolic pressure, when your heart relaxes. But what is considered a healthy range to be in can depend on where in the world you are – in the US, for example, blood pressure was considered to be high if it was over 140/90mmHg but in 2017, <a href="https://www.sciencedaily.com/releases/2018/11/181119064126.htm">the threshold was changed</a> to include readings over 130/80mmHg.</p>
<h2>The effect of age</h2>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/295434/original/file-20191003-52857-h0oh7f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/295434/original/file-20191003-52857-h0oh7f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=532&fit=crop&dpr=1 600w, https://images.theconversation.com/files/295434/original/file-20191003-52857-h0oh7f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=532&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/295434/original/file-20191003-52857-h0oh7f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=532&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/295434/original/file-20191003-52857-h0oh7f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=669&fit=crop&dpr=1 754w, https://images.theconversation.com/files/295434/original/file-20191003-52857-h0oh7f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=669&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/295434/original/file-20191003-52857-h0oh7f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=669&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cross section of an artery, showing an atheroma (blockage) on the left.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cross-section-artery-showing-atheroma-plaque-455301583?src=D_4SzoepwPgwe3djBuff9w-1-6">Jose Luis Calvo/Shutterstock</a></span>
</figcaption>
</figure>
<p>As we get older, many people have an associated increase in blood pressure, clinically referred to as hypertension. Most of us know that as we age our skin loses its stretchy capability and we get wrinkles. Your blood vessels also age and lose their elasticity, which leads to what is often termed “stiffness” of your blood vessels. This is potentially exacerbated by an accumulation of fatty material in the wall of blood vessels over time, known as an atheroma. This accumulation builds up over years through a process known as atherosclerosis, where small lesions, originating in damaged areas of blood vessels develop into large plaques, which ultimately reduce the internal volume of the vessel internal and restricts blood flow. </p>
<p>This blockage can occur in any blood vessel leading to an acute or chronic problem. If located in the coronary artery, which supplies the heart muscle with oxygen – it will result in a heart attack or chest pain known as <a href="https://www.nhs.uk/conditions/angina/">angina</a>. However, a blockage of the <a href="https://www.ncbi.nlm.nih.gov/pubmed/30739271">carotid artery</a> – an artery found in your neck – would reduce blood flow to your brain and cause <a href="https://www.nhs.uk/conditions/stroke/">a stroke</a>.</p>
<h2>High readings</h2>
<p>In the UK, your blood pressure will be classified in a NHS clinic according to <a href="https://www.nice.org.uk/guidance/ng136/chapter/Recommendations">official NICE guidelines</a>. A first reading of 140/90mmHg or higher, will result in a second measurement and a third measurement. If there are substantial differences, the lower reading is recorded. If this is 140/90mmHg or above you will be diagnosed with high blood pressure. </p>
<p>There are also different tiers of high blood pressure. NICE currently <a href="https://bnf.nice.org.uk/treatment-summary/hypertension.html">states that</a>: “Stage 1 hypertension is where a clinical blood pressure is 140/90mmHg or higher,” whereas “Stage 2 hypertension is where a clinic blood pressure is 160/100mmHg or higher”. Those with “severe hypertension possess at clinic a systolic blood pressure [that] is 180mmHg or higher, or a diastolic blood pressure at 110mmHg or higher”.</p>
<p>However, the American College of Cardiology and the <a href="https://www.ahajournals.org/doi/10.1161/HYP.0000000000000065">American Heart Association</a>, the advisory body in the US, drastically reduced their thresholds for diagnosis; in the US, Stage 1 hypertension is classed as a systolic pressure of 130mmHg or over, and Stage 2 is over 140mmHg. Considering this adjustment, the US expect more than 46% of the adult population <a href="https://www.ahajournals.org/doi/10.1161/HYP.0000000000000065">to have high blood pressure</a>, and more specifically for those over the age of 45, the diagnosis is expected to triple in men and double in women.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-exactly-is-a-disease-120622">What exactly is a disease?</a>
</strong>
</em>
</p>
<hr>
<h2>Risk factors</h2>
<p>The idea of lowering thresholds of high blood pressure in the UK <a href="https://www.bmj.com/content/366/bmj.l5315">has been mooted</a>. The reason is that high blood pressure is a key factor for predicting your individual risk of a cardiovascular problem.</p>
<p>Some of these <a href="https://www.nhs.uk/conditions/high-blood-pressure-hypertension/causes/">risk factors</a> are non-modifiable such as your age, race, gender born, family history and genetics, however others are modifiable such as blood pressure, blood cholesterol, body-mass index (BMI) – calculated from your weight and height – and of course lifestyle choices such as diet, physical activity, smoking/vaping and alcohol consumption.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/295433/original/file-20191003-52801-xinf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/295433/original/file-20191003-52801-xinf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/295433/original/file-20191003-52801-xinf1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/295433/original/file-20191003-52801-xinf1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/295433/original/file-20191003-52801-xinf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/295433/original/file-20191003-52801-xinf1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/295433/original/file-20191003-52801-xinf1.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">Lifestyle factors such as diet can impact your blood pressure.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/salt-causes-heart-disease-1089292808?src=yYM8_oEZtarKX2tc3-sJuw-2-22">Sharif Pavlov/Shutterstock</a></span>
</figcaption>
</figure>
<p>A <a href="http://www.onlinejacc.org/content/early/2017/11/04/j.jacc.2017.11.006?_ga=2.82057109.2031920225.1510603048-230608748.1510603048">clinical study</a> (nicknamed SPRINT – Systolic Blood Pressure Intervention Trial) took 9,361 people aged over 50 with at least one cardiovascular risk factor or with pre-existing kidney disease, and who used pharmaceutical drugs to lower blood pressure in accordance with new US guidelines. </p>
<p>SPRINT found a 25% relative reduction in the risk of death during the six year follow up among those people treated intensively to reach the 120mmHg target, compared with those treated to 140mmHg. This led to early termination of the study as it showed an obvious benefit to lowering resting blood pressure to 120mmHg or less, and gave a 30% lower <a href="https://www.ncbi.nlm.nih.gov/books/NBK63647/">relative risk</a> of cardiovascular problems such as stroke or heart attacks on follow up. </p>
<p>As such there is a clear argument that to maintain a typical blood pressure in the UK (120/70mmHg) should be the target for us all.</p><img src="https://counter.theconversation.com/content/124658/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sandra Jones receives funding from the Hull and East Riding Cardiac Trust Fund charity. She is a fellow of The Physiological Society and a member of the American Heart Association. </span></em></p><p class="fine-print"><em><span>Matthew Lancaster receives funding from The British Heart Foundation. He is a member of The Physiological Society and American Heart Association.</span></em></p>How to interpret the readings to tell if you have high blood pressure.Sandra Jones, Senior Lecturer in Biomedical Science, University of HullMatthew Lancaster, Associate Professor in Biological Sciences, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1223462019-09-11T10:11:29Z2019-09-11T10:11:29ZWhy fidgeting could be good for your child’s health<figure><img src="https://images.theconversation.com/files/290324/original/file-20190830-165997-17ycqxz.jpg?ixlib=rb-1.1.0&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/young-boy-laying-on-couch-holding-1103428211?src=-1-22">Shutterstock</a></span></figcaption></figure><p>Fidgeting is usually considered as a sign of boredom or lack of attention which can be distracting to others. Parents and teachers often demand that their children and pupils stop doing it. But fidgeting could actually be good for their health. Research suggests it might help protect against obesity, improve cardiovascular health, and even save lives.</p>
<p>In our <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0215169">recent study</a> we measured the energy expenditure of 40 children aged four to six, while they each spent an hour in a “whole-room calorimeter”. This is a chamber the size of a small bedroom, in which energy expenditure is accurately measured from the amount of oxygen breathed in and the amount of carbon dioxide breathed out. </p>
<p>The children all followed the same procedure in the calorimeter: 30 minutes watching TV, ten minutes drawing or colouring in, and 20 minutes playing with toys on the floor. We counted the number of times children changed posture and took that as our measure of fidgeting. </p>
<p>The fidgeting we witnessed – with colleagues from the Australian universities of Wollongong and Deakin – varied enormously, despite all of the children following the standard set of activities. There were 53 posture changes per hour in the most fidgety third of the sample, and only 11 per hour in the least fidgety third. These differences directly affected the number of calories burned. </p>
<p>The difference between most and least fidgety groups was only around six calories per hour. But when extrapolated over months and years, this could lead to large differences in energy use. </p>
<p>After all, children of that age <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(03)15331-7/fulltext">typically spend</a> around nine to ten hours per day sitting down, so a six calorie difference per hour of sitting would become a difference of 60 calories per day, 420 calories per week (about three bags of crisps), and 22,000 calories per year (equivalent to about 2kg of body weight in a 20kg child).</p>
<p>We also found that children were much less fidgety while watching TV than when drawing, colouring, or playing with toys on the floor. This may partly explain why time spent watching TV <a href="https://epha.org/watching-tv-increases-the-risk-of-obesity/">increases the risk of obesity</a> so strongly in children of this age compared to other sedentary activities.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-screen-time-for-babies-children-and-adolescents-needs-to-be-limited-110630">Why screen time for babies, children and adolescents needs to be limited</a>
</strong>
</em>
</p>
<hr>
<p>Meanwhile, an <a href="https://science.sciencemag.org/content/283/5399/212">older study</a>
found that more fidgety adults resisted weight gain when overfed compared to less fidgety individuals. Taken together, this evidence suggests that differences in the tendency to fidget might partly explain why some people are more susceptible to obesity than others.</p>
<h2>Fidgeting as health strategy?</h2>
<p>It is now well established that prolonged periods of sitting are harmful to health, and it is possible that fidgeting might reduce the harms of sitting. A <a href="https://www.ncbi.nlm.nih.gov/pubmed/26416340">study of more than 12,000 adult women in the UK</a> found, as expected, that the amount of time spent sitting per day predicted the risk of premature death over the subsequent 12 years. </p>
<p>At the start of the study the women had been asked to self-rate their tendency to fidget on a scale of one (no fidgeting) to ten (constant fidgeting). In the most fidgety third, the risks of premature death from sitting were substantially reduced compared to the least fidgety third. </p>
<p>Why fidgeting seemed to reduce premature mortality was not explored in that study. However, a more recent <a href="https://www.ncbi.nlm.nih.gov/pubmed/27233765">laboratory-based study in adults</a> found that the harmful effects of prolonged sitting on blood vessels in the legs (such as reduced blood flow) could be mitigated by asking the study participants to fidget by moving their legs while sitting. Fidgety individuals may have some protection from cardiovascular disease compared to less fidgety individuals </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/290923/original/file-20190904-175705-16yvtmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290923/original/file-20190904-175705-16yvtmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290923/original/file-20190904-175705-16yvtmk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290923/original/file-20190904-175705-16yvtmk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290923/original/file-20190904-175705-16yvtmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290923/original/file-20190904-175705-16yvtmk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290923/original/file-20190904-175705-16yvtmk.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">Sofa-based moves.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/exuberant-young-woman-listening-music-she-1033351399?src=-1-27">Shutterstock/stockfour</a></span>
</figcaption>
</figure>
<p>Fidgeting is not considered as being important to health at the moment, but the growing body of research suggests that it should be. The evidence might even lead to new (and much needed) approaches to preventing obesity and promoting cardiovascular health. </p>
<p>Such approaches might be particularly practical as they involve fairly small changes in how we live. Fidgeting or standing breaks during long periods of sitting in the classroom, or at home, far from being an annoying habit, could be precisely what we need.</p><img src="https://counter.theconversation.com/content/122346/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John J Reilly receives funding from The Hannah Research Foundation and The Cunningham Trust.</span></em></p><p class="fine-print"><em><span>Xanne Janssen 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 may not be such a bad habit after all.John J Reilly, Professor of Physical Activity and Public Health Science, University of Strathclyde Xanne Janssen, Research Associate, University of Strathclyde Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1174912019-05-22T18:12:52Z2019-05-22T18:12:52ZGenetic trigger discovered for common heart problem, mitral valve prolapse<figure><img src="https://images.theconversation.com/files/275729/original/file-20190521-23820-17fp8ze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mitral valve prolapse is one of the most common heart disorders worldwide.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/men-white-shirt-having-chest-pain-213185284?src=2b5RuZ4NtRm9cmSttTxUnA-1-20">Hriana/Shutterstock.com</a></span></figcaption></figure><p>Ever been to a large sporting event, such as a football or baseball game with 60,000 screaming fans? What you don’t hear through the screams is a clicking sound in the chests of about 1,500 of these fans who have a heart valve disease. And it’s likely that one or two of those are sitting in your row. </p>
<p>Many of these people may, during the excitement of the game, feel that something is not right with their heart. But the problem doesn’t seem severe. So they ignore the sensation of feeling faint or weak, and they continue watching the game. </p>
<p>During a checkup with their primary care physician, however, their doctor might hear the “click” inside their chest. That’s a sign of a potential problem with their heart valves. After they follow up with a cardiologist, they are often diagnosed with a common heart valve disease called <a href="https://www.nhlbi.nih.gov/health-topics/mitral-valve-prolapse">mitral valve prolapse</a>. Although one of the most common cardiovascular diseases, doctors have not understood the causes of this disease. </p>
<p><a href="http://cba.musc.edu/Faculty/NorrisR.htm">I</a> have been studying heart valve disease for over 20 years and initially became interested in heart valves after I learned that members of my own family had suffered from mitral valve prolapse. This led me to work with <a href="http://regmed.musc.edu/Faculty/MarkwaldR.htm">Roger Markwald</a>, a pioneer in the field of cardiac valve development. Together, we have been part of large collaborative network to study heart valve disorders. One of these international consortiums has now discovered a <a href="https://stm.sciencemag.org/lookup/doi/10.1126/scitranslmed.aax0290">genetic cause of mitral valve prolapse</a>.</p>
<h2>What is mitral valve prolapse?</h2>
<p>The heart is a complicated organ, and there are many things that can go awry. In <a href="https://www.nhlbi.nih.gov/health-topics/mitral-valve-prolapse">mitral valve prolapse</a>, the two mitral valve leaflets, or flaps, are located on the left side of your heart and are positioned between the left atrium and left ventricle. These valves function as one-way doors, enabling blood flow in only one direction.</p>
<p>In patients with mitral valve prolapse, the doors become warped and can’t quite close all the way. As a result, blood can flow back into the left atrium and not out to the rest of the body where it should be going. This is called regurgitation. The more <a href="http://doi.org/10.1056/NEJMoa041451">regurgitation a person has, the higher the risk of additional complications</a>, including death. The condition affects <a href="http://doi.org/10.1056/NEJM199907013410101">one in 40 people</a> and is one of the most common cardiovascular diseases worldwide.</p>
<p>Surgery to repair the mitral valve is the fastest-growing cardiovascular intervention in the United States, <a href="https://doi.org/10.1016/j.athoracsur.2018.03.086">increasing by more than 40% since 2011</a>. </p>
<h2>Embryonic origins of disease</h2>
<p>While mitral valve prolapse is common, doctors have not known its causes. It wasn’t until today that <a href="https://stm.sciencemag.org/lookup/doi/10.1126/scitranslmed.aax0290">I and my colleagues reported</a> a genetic and biological trigger for the disease.</p>
<p>Tackling this complex clinical problem required an international team of geneticists, cardiologists, echo-cardiographers and surgeons all collaborating to identify genetic and molecular causes for mitral valve prolapse in a multigenerational family of 43 members, 11 of whom suffered from this disorder. Our team also used data from more than 1,400 unrelated patients with mitral valve prolapse. </p>
<p>Using the DNA from the members of the large family, I and my colleagues identified a mutation in a gene called DZIP1. My team members genetically engineered mice with this exact mutation to provide a way of understanding how and why the disease begins and how it progresses. The models fully recapitulated the human disease and, to our surprise, revealed that mitral valve prolapse – which is normally identified in the aging population – originates during embryonic development.</p>
<p>This means that the blueprints for how these heart valves form in mitral valve prolapse patients are altered from the outset; it’s like a house being built with faulty bricks. Over time, the structure of such a house begins to fail. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275727/original/file-20190521-23826-hjvqwh.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 mitral valves are located on the left side of the heart. In patients with mitral valve prolapse, the valves fail to come together properly and billow back into the left atrium. In many of these patients, this can result in blood going backward, into the left atrium, as shown in the right panel.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/heart-mitral-valve-prolapse-on-blue-1010068843">EstherQueen999/Shutterstock.com</a></span>
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</figure>
<h2>A biological explanation</h2>
<p>Our group has found that the “bricks” of the heart valves, known as valve interstitial cells, require tiny hair-like structures called primary cilia to form and function properly. The cilia function as cellular antennae to receive signals from the surrounding environment, much like an antenna on top of your house. However, in many patients with mitral valve prolapse, these antennae are absent or defective, and the cells lose their ability to sense their surroundings. </p>
<p>As a consequence, the normal structure of the valve becomes altered and over time leads to mitral valve prolapse. </p>
<p>So, how does this finding help physicians treat mitral valve prolapse? Well, it’s going to take some more time and more funding to figure that out. </p>
<p>Surgery is currently the only effective curative option for mitral valve prolapse. But now that the first animal model for this disease has been created that is based on genetic mutations found in patients, scientists can begin testing how drugs can stop the disease from progressing or reverse the defects that happened early in life.</p><img src="https://counter.theconversation.com/content/117491/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Russell Norris receives funding from the National Institutes of Health, American Heart Association and the Leducq Foundation. </span></em></p>Using a large family whose members suffered from mitral valve prolapse, one of the most common heart diseases worldwide, researchers have discovered one cause of the disorder.Russell Norris, Associate Professor of Regenerative Medicine and Cell Biology, Medical University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1103252019-01-30T13:12:41Z2019-01-30T13:12:41ZNorthern millennials less likely to live into their 50s than their southern English counterparts<figure><img src="https://images.theconversation.com/files/256375/original/file-20190130-108355-1r6ttok.jpg?ixlib=rb-1.1.0&rect=0%2C606%2C4767%2C3030&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/one-antony-gormleys-cast-iron-statues-1252542793?src=PDavuMpgEPqutgUollud7Q-1-12">Christopher Middleton/Shutterstock.</a></span></figcaption></figure><p>There is a stark disparity in wealth and health between people in the north and south of England, commonly referred to as England’s “north-south divide”. The causes of this inequality are complex; it’s influenced by the environment, jobs, migration and lifestyle factors – as well as the long-term political power imbalances, which have <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/662744/State_of_the_Nation_2017_-_Social_Mobility_in_Great_Britain.pdf">concentrated resources and investment</a> in the south, especially in and around London. </p>
<p>Life expectancy is also lower in the north, mainly because the region is more deprived. But <a href="https://jech.bmj.com/content/71/9/928">new analysis</a> of national mortality data highlights a shockingly large mortality gap between young adults, aged 25 to 44, living in the north and south of England. This gap first emerged in the late 1990s, and seems to have been growing ever since.</p>
<p>In 1995, there were 2% more deaths among northerners aged 25 to 34 than southerners (in other words, 2% “excess mortality”). But by 2015, northerners in this age group were 29% more likely to die than their southern counterparts. Likewise, in the 35 to 44 age group, there was 3% difference in mortality between northerners and southerners in 1995. But by 2015, there were 49% more deaths among northerners than southerners in this age group. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=573&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=573&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255115/original/file-20190123-135154-1iik2m8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=573&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">Excess mortality in the north compared with south of England by age groups, from 1965 to 2015. Follow the lines to see that people born around 1980 are the ones most affected around 2015.</span>
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</figure>
<p>While mortality increased among northerners aged 25 to 34, and plateaued among 35 to 44-year-olds, southern mortality mainly declined across both age groups. Overall, between 2014 and 2016, northerners aged 25 to 44 were 41% more likely to die than southerners in the same age group. In real terms, this means that between 2014 and 2016, 1,881 more women and 3,530 more men aged between 25 and 44 years died in the north, than in the south. </p>
<h2>What’s killing northerners?</h2>
<p>To understand what’s driving this mortality gap among young adults, our team of researchers looked at the causes of death from 2014 to 2016, and sorted them into eight groups: accidents, alcohol related, cardiovascular related (heart conditions, diabetes, obesity and so on), suicide, drug related, breast cancer, other cancers and other causes.</p>
<p>Controlling for the age and sex of the population in the north and the south, we found that it was mostly the deaths of northern men contributing to the difference in mortality – and these deaths were <a href="https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(18)30177-4/fulltext">caused mainly</a> by cardiovascular conditions, alcohol and drug misuse. Accidents (for men) and cancer (for women) also played important roles.</p>
<iframe src="https://datawrapper.dwcdn.net/gjwhO/1/" scrolling="no" frameborder="0" width="100%" height="400"></iframe>
<p>From 2014 to 2016, northerners were 47% more likely to die for cardiovascular reasons, 109% for alcohol misuse and 60% for drug misuse, across both men and women aged 25 to 44 years old. Although the national rate of death from cardiovascular reasons <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5268076/">has dropped since 1981</a>, the longstanding gap between north and south remains. </p>
<h2>Death and deprivation</h2>
<p>The gap in life expectancy between north and south is usually put down to socioeconomic deprivation. We considered further data for 2016, to find out if this held true for deaths among young people. We found that, while two thirds of the gap were explained by the fact that people lived in deprived areas, the remaining one third could be caused by some unmeasured form of deprivation, or by differences in culture, infrastructure, migration or extreme weather.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/255333/original/file-20190124-135142-3kgzy1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255333/original/file-20190124-135142-3kgzy1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=658&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255333/original/file-20190124-135142-3kgzy1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=658&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255333/original/file-20190124-135142-3kgzy1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=658&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255333/original/file-20190124-135142-3kgzy1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=827&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255333/original/file-20190124-135142-3kgzy1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=827&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255333/original/file-20190124-135142-3kgzy1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=827&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mortality for people aged 25 to 44 years in 2016, at small area geographical level for the whole of England.</span>
</figcaption>
</figure>
<p>Northern men faced a higher risk of dying young than northern women – partly because overall mortality rates are higher for men than for women, pretty much at every age, but also because men tend to be <a href="https://www.bmj.com/content/345/bmj.e5142">more susceptible to socioeconomic pressures</a>. Although anachronistic, the expectation to have a job and be able to sustain a family weighs more on men. Accidents, alcohol misuse, drug misuse and suicide are all strongly associated with low socioeconomic status.</p>
<p>Suicide risk is twice as high among the most deprived men, compared to the most affluent. Suicide risk <a href="https://www.bmj.com/content/317/7168/1283.long">has also been associated</a> with unemployment, and substantial increases in suicide have been observed during periods of recession – especially among men. <a href="https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1360-0443.1999.9412187112.x">Further evidence</a> tells us that unskilled men between ages 25 and 39 are between ten and 20 times more likely to die from alcohol-related causes, compared to professionals.</p>
<p>Alcohol underpins the steep increase in liver cirrhosis deaths in Britain from the 1990s – which is when the north-south divide in mortality between people aged 25 to 44 also started to emerge. <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-10-99">Previous research</a> has shown that men in this age group, who live in the most deprived areas, are five times more likely to die from alcohol-related diseases than those in the most affluent areas. For women in deprived areas, the risk is four times greater. </p>
<p>It’s also widely known that mortality rates for cancer <a href="https://www.cancerresearchuk.org/health-professional/cancer-statistics/mortality/deprivation-gradient2018">are higher in more deprived areas</a>, and people have worse survival rates in places where smoking and alcohol abuse is more prevalent. Heroin and crack cocaine addiction and deaths from drug overdoses are also <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)61462-6/fulltext">strongly associated</a> with deprivation.</p>
<p>The greater number of deaths from accidents in the north should be considered in the context of transport infrastructure investment, which is heavily skewed towards the south – especially London, which enjoys the lowest mortality in the country. What’s more, if reliable and affordable public transport is not available, people will drive more and expose themselves to higher risk of an accident.</p>
<p>Deaths for young adults in the north of England have been increasing compared to those in the south since the late 1990s, creating new health divides between England’s regions. It seems that persistent social, economic and health inequalities are responsible for a growing trend of psychological distress, despair and risk taking among young northerners. Without major changes, the extreme concentration of power, wealth and opportunity in the south will continue to damage people’s health, and worsen the north-south divide.</p><img src="https://counter.theconversation.com/content/110325/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Evangelos Kontopantelis has received funding from the NIHR, the MRC and The Health Foundation. </span></em></p>Regional deprivation is causing thousands of northerners – especially men – to die young each year.Evangelos Kontopantelis, Professor in Data Science and Health Services Research, University of ManchesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1068612018-11-14T19:01:38Z2018-11-14T19:01:38ZDespite new findings, the jury is still out on whether omega-3 supplements reduce heart attacks<figure><img src="https://images.theconversation.com/files/245456/original/file-20181114-194494-6h98h2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Omega-3s reduce the risk of blood clots and are anti-inflammatory.</span> <span class="attribution"><span class="source">from shutterstock.com</span></span></figcaption></figure><p>A recent <a href="https://www.news.com.au/technology/science/human-body/big-studies-give-mixed-news-on-fish-oil-vitamin-d/news-story/1d0ed27167c50c88d9a1a316efda3c62">widely-reported</a> study has <a href="http://fortune.com/2018/11/12/fish-oil-amarin-vascepa/">reignited debate</a> around whether omega-3 supplements reduce the risk of heart attack and stroke. The study showed a particular form of omega-3 oil lowered the risk of people with heart disease experiencing a major “end point” event by 25%. This end point is one or a combination of several serious issues such as fatal or non-fatal heart attack, stroke, angina (chest pain) and coronary surgery.</p>
<p>The REDUCE-IT trial included more than 8,000 participants and was presented at the American Heart Association Scientific Sessions in Chicago and published in the <a href="https://www.nejm.org/doi/pdf/10.1056/NEJMoa1812792">New England Journal of Medicine</a>. It was the largest randomised controlled trial (where one group is given the intervention tested and another a placebo and the results are compared) performed to-date testing the benefits of omega-3 supplements for heart disease.</p>
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Read more:
<a href="https://theconversation.com/randomised-control-trials-what-makes-them-the-gold-standard-in-medical-research-78913">Randomised control trials: what makes them the gold standard in medical research?</a>
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<p>But before you buy fish oil supplements from the local pharmacy, there are some things to be aware of. The drug tested, Vascepa, wasn’t a standard over-the-counter fish oil capsule. Vascepa is made from a highly refined component of fish oils (icosapent ethyl) and the participants received a very high dose (4 grams per day). This is far more omega-3 than most people take with fish oil capsules. Vascepa is available on prescription in the US but not everywhere, and not in Australia.</p>
<p>The study participants either had cardiovascular disease and were aged over 45, or were at high risk of cardiovascular disease and aged over 50. Those at risk had diabetes and at least one other risk factor. The results apply best to people with similar characteristics to the study group and cannot necessarily be generalised more broadly.</p>
<p>Nevertheless, it was a pretty good study performed by reputable investigators across 11 countries with convincing results. So, what does this mean for the see-saw of advice offered on whether to take or not to take fish oil supplements to prevent major heart issues?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/245488/original/file-20181114-194519-1jqwuy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Not everyone with heart disease would necessarily benefit from the supplements participants received in the trial.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<h2>A bit of history</h2>
<p>In the early 2000s medical authorities were recommending fish oil supplementation for people who had experienced a cardiovascular event such as a heart attack or stroke. </p>
<p>At that time, <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(99)07072-5/fulltext">two large</a> <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(99)07072-5/fulltext">randomised controlled trials</a> reported that eicosapentaenoic acid supplements (which contained EPA and docosahexaenoic acid (DHA)) significantly reduced fatal heart disease. EPA and DHA are the major oils found in fish oil supplements and are called omega-3s.</p>
<p>In 2017 the <a href="https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000000482?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed%5C&">American Heart Association</a> was more circumspect, noting that the dramatic benefits seen earlier were less evident in subsequent trials. But supplements were still recommended for certain people with heart or vascular disease.</p>
<p>By early 2018, the tide seemed to have turned completely as a widely publicised study concluded there was little evidence for the benefit of fish oil supplements in preventing heart disease. The study was a systematic review, <a href="https://jamanetwork.com/journals/jamacardiology/fullarticle/2670752">which combined</a> the results of ten trials testing fish oil supplements (at a lower dose than the REDUCE-IT trial), involving 77,917 older adults at high risk of cardiovascular disease. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-fish-oil-anyone-26114">Health Check: fish oil, anyone?</a>
</strong>
</em>
</p>
<hr>
<p>So, what are we to believe? A well-conducted randomised controlled trial or a systematic review of all the evidence? An RCT is considered gold standard by guideline committees. A well-done systematic review or meta-analysis is also considered as providing powerful evidence.</p>
<h2>So, what’s the verdict?</h2>
<p>The trials in the systematic review varied widely in design, dose, patient population, end points and the validity of lumping them all together is questionable. Also, finding no evidence of benefit is not the same as finding no benefit, particularly in some people under certain conditions that may be lost in the overall analysis. Plus, the results are not just a reflection of the treatment under examination but also of the <a href="https://jamanetwork.com/journals/jama/article-abstract/2654401">quality of the studies</a> included.</p>
<p>REDUCE-IT was funded by the manufacturer. There is no other way it would have been done and if the results stand up it could save millions of lives, but some will question the veracity of the findings because of the funding source. So, all of this leaves certainty of whether supplements are good for heart health up in the air.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/245490/original/file-20181114-194519-eomkau.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">It’s still a fact that cold water fish are good for you.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>Fortunately (and as far as we know) some “truths” remain. Eating fish is still <a href="https://jamanetwork.com/journals/jama/fullarticle/203640">good for you</a>. The origin of the fish is important, not only to avoid contaminants but also because the omega-3 content and relative amounts of EPA and DHA varies. Cold water, oily fish such as salmon, sardines, mackerel, trout and tuna contain the most.</p>
<p>If you cannot eat fish, there are plant sources of omega-3s found in some nuts and vegetable oils such as canola, chia, flaxseed, and soy. These have not been studied as extensively as those of marine origin.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-australians-die-cause-1-heart-diseases-and-stroke-57423">How Australians Die: cause #1 – heart diseases and stroke</a>
</strong>
</em>
</p>
<hr>
<p>Omega-3s including over the counter capsules <a href="https://www.nejm.org/doi/pdf/10.1056/NEJMoa1812792">have definite biological effects</a>. They reduce triglycerides (the type of fat that contributes to hardening of the arteries) and the risk of blood clots, and are anti-inflammatory. These changes are mostly seen at higher doses. </p>
<p>The evidence will evolve further but, in the meantime, and based on a recent evidence review, the <a href="https://doi.org/10.1016/j.hlc.2015.03.020">National Heart Foundation recommendations</a> don’t advise health professionals to routinely recommend omega-3 supplements for heart health. It does advise health professionals consider the use of omega-3 supplements for those with high triglyceride levels and as an additional treatment for heart failure. </p>
<p>And lastly, everyone should include two to three serves of fish per week in their diet.</p><img src="https://counter.theconversation.com/content/106861/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Garry Jennings receives funding from the National Health and Medical Research Council.He is affiliated with the National Heart Foundation, Sydney Health Partners (University of Sydney) and Baker Heart & Diabetes Institute.. </span></em></p>A new study has found one type of concentrated fish oil supplement reduces the risk of heart attacks and stroke among people with heart disease. But these findings apply to a certain group of people.Garry Jennings, Professor of Medicine, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/976992018-06-24T19:50:49Z2018-06-24T19:50:49ZGetting a heart check early can prevent heart attack and stroke in Indigenous Australians<figure><img src="https://images.theconversation.com/files/222928/original/file-20180613-153638-iftah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Only around half of at-risk Indigenous Australians are taking preventative medication for heart disease. </span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>Most heart attacks and strokes can be prevented with appropriate treatment. Yet heart disease, including heart attacks, <a href="https://www.heartfoundation.org.au/about-us/what-we-do/heart-disease-in-australia/cardiovascular-risk-profile-of-aboriginal-and-torres-strait-islander-peoples">causes 13%</a> of deaths among Australia’s Aboriginal and Torres Strait Islander peoples and is a major contributor to the gap in life expectancy with non-Indigenous Australians. </p>
<p>New findings from a study published today in the <a href="http://dx.doi.org/10.5694/mja17.00897">Medical Journal of Australia</a> show vast room for improvement in heart health among Aboriginal and Torres Strait Islander peoples.</p>
<h2>Who is at risk?</h2>
<p>This <a href="http://dx.doi.org/10.5694/mja17.00897">new research</a> found 10% of Aboriginal and Torres Strait Islander people aged 35-74 years old have heart disease (<a href="https://www.mja.com.au/system/files/issues/204_08/10.5694mja15.01004.pdf">compared to 9%</a> aged 45-74 in the general population). Another 16% are at high risk of getting heart disease (<a href="https://www.mja.com.au/system/files/issues/204_08/10.5694mja15.01004.pdf">compared to 11%</a> aged 45-74 in the general population), defined in Australia as a greater than 15% chance of getting heart disease in the next five years.</p>
<p>A heart check involves calculating how likely a person is to develop heart disease over a specific time period (five years in Australia). This involves gathering information from multiple factors including a person’s age, sex, smoking status, whether they have diabetes and their blood pressure and cholesterol levels.</p>
<p><a href="https://www.heartfoundation.org.au/images/uploads/publications/Absolute-CVD-Risk-Full-Guidelines.pdf">Australia’s national guidelines</a> recommend all Aboriginal and Torres Strait Islander peoples aged 35-74 have a heart check. But this <a href="http://dx.doi.org/10.5694/mja17.00897">new research</a> found the “high risk” category starts much earlier than this. </p>
<p>Around 1.1% of Aboriginal and Torres Strait Islander 18-24 year olds and 4.7% of 25-34 year olds were at high risk of heart disease. This is around the same as the proportion of <a href="https://www.mja.com.au/system/files/issues/204_08/10.5694mja15.01004.pdf">non-Indigenous Australians</a> aged 45-54 who are at high risk. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/222929/original/file-20180613-153682-1e0hhab.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"></a>
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<span class="caption">Too few Indigenous peoples are having heart checks.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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</figure>
<h2>Potential to prevent events through medication</h2>
<p>Heart disease risk can be lowered through lifestyle changes, including giving up smoking, losing weight and exercising more, as well as using medications that lower blood pressure and cholesterol levels. Generally, all people who have heart disease and those at high risk should be prescribed <a href="https://www.heartfoundation.org.au/images/uploads/publications/Absolute-CVD-Risk-Full-Guidelines.pdf">preventative medications</a>.</p>
<p>Yet this latest evidence shows only 53% of Aboriginal and Torres Strait Islander peoples with existing heart disease and 42% of those at high risk were using cholesterol-lowering medications. We don’t know the exact reasons for this. It could be due to a number of things including people not getting a heart check in the first place, and not continuing to use medications when they have been prescribed. </p>
<p>We don’t know the exact number of Aboriginal and Torres Strait Islander people receiving a heart check, but we do know overall numbers are low and it varies by region. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4781864/">Estimates</a> among Aboriginal and Torres Strait Islander people with diabetes found rates of heart checks ranged from about 3% of people in participating health centres in Queensland, South Australia and Western Australia to around 56% in the Northern Territory. </p>
<p>This highlights the huge potential to prevent future heart attack and stroke in these communities by improving treatment in people at high risk.</p>
<h2>What can we do?</h2>
<p>These findings highlight multiple actions that can be taken to improve heart disease prevention. First, this new evidence suggests the age to start doing heart checks should be lowered in Australian guidelines. This decision would need to be jointly undertaken with Aboriginal and Torres Strait Islander communities. </p>
<p>GPs and nurses should be proactive in identifying Aboriginal and Torres Strait Islander patients, providing heart and overall health checks, and following up with patients. </p>
<p>The Northern Territory is a good example. There, the number of Aboriginal and Torres Strait Islander peoples receiving a heart check <a href="https://www.heartlungcirc.org/article/S1443-9506(14)00771-9/pdf">more than doubled</a> after improvements in reporting, monitoring and follow-up. Improving the rate of health checks for adolescents and young adults is particularly important so discussions and treatment decisions can take place early.</p>
<p>Programs aimed at prevention should also be co-designed with Aboriginal and Torres Strait Islander peoples, taking into account social and cultural barriers that impact access and ongoing treatment.</p>
<p>The good news is, we know heart attacks and strokes can be prevented and we have effective treatments to achieve this. Within Aboriginal and Torres Strait Islander communities there is huge potential to prevent heart attacks and stroke. </p>
<p>Many people don’t receive a heart check and could be at high risk without knowing it. Prevention starts with getting a heart check and continuing to use any medications prescribed to you by your doctor to lower your risk.</p><img src="https://counter.theconversation.com/content/97699/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ellie Paige is an investigator on a project on Aboriginal and Torres Strait Islander absolute cardiovascular disease risk funded by the Commonwealth Department of Health.</span></em></p><p class="fine-print"><em><span>Sandra Eades receives funding from National Health and Medical Research Council.</span></em></p><p class="fine-print"><em><span>Vicki Wade is an investigator on a study looking at absolute risk in Aboriginal and Torres Straight Islander peoples funded by the Commonwealth Department of Health.</span></em></p>A new study has found too few Indigenous people are getting health checks, despite their elevated risk of heart problems.Ellie Paige, Research Fellow, Australian National UniversitySandra Eades, Professor and Head: Aboriginal Health, Baker Heart and Diabetes InstituteVicki Wade, Senior Cultural Advisor, Rheumatic Heart Disease Australia, Menzies School of Health ResearchLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/870552017-11-09T13:17:44Z2017-11-09T13:17:44ZWhy saunas really are good for your health<figure><img src="https://images.theconversation.com/files/193945/original/file-20171109-27169-sj5gew.jpg?ixlib=rb-1.1.0&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/sauna-finland-749302972?src=RzTLpSMryjC61hIpnd3ELA-1-38">Shutterstock</a></span></figcaption></figure><p>Things are hotting up in the world of sauna research. Previously, anecdotal claims of possible benefits were rarely backed up by medical evidence. But recent studies have shown that taking a regular sauna can be extremely good for your health – alleviating and preventing the risk of common acute and chronic conditions. </p>
<p>Sauna “bathing” is a form of passive heat therapy which originates from Finland and is mostly associated with Nordic countries. It is used mainly for pleasure and relaxation, and involves spending short periods of time (usually five to 20 minutes) in temperatures of 80°C to 100°C, interspersed with moments of cooling-off in a pool or shower. </p>
<p>Although there are other forms of heat therapy such as Turkish baths, infrared saunas, and Waon therapy, the traditional Finnish sauna is the most examined to date. In <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2130724">a 2015 study</a>, scientists from the University of Eastern Finland recorded the sauna bathing habits of 2,300 men, and tracked their health for more than two decades. </p>
<p>They found that those who used saunas regularly suffered from dramatically fewer deaths from heart disease or stroke. In a <a href="https://academic.oup.com/ageing/article/46/2/245/2654230">follow-up study</a> by the same group the following year, regular sauna sessions were found to substantially reduce the risk of dementia. </p>
<p>Our <a href="https://academic.oup.com/ajh/article/doi/10.1093/ajh/hpx102/3867393">latest research</a> this year involved recording the habits and health of 1,621 men over 22 years. Having regular saunas (four to seven times a week) was shown to slash the risk of high blood pressure by almost 50%. </p>
<p>Scientists are not certain how saunas reduce heart disease, but one theory is that they contribute to a reduction in high blood pressure, one of the condition’s major risk factors. Additionally, the heat from the sauna causes an increase in heart rate and widening of blood vessels in the skin. This leads to increased blood flow, which improves cardiovascular function and subsequently reduces the risk of heart disease. </p>
<p>Sauna bathing has been shown to produce effects similar to that of exercise, which is well known to prevent the development of several disease conditions. In fact, scientists from the Universities of Bristol and Eastern Finland <a href="http://www.tandfonline.com/doi/abs/10.1080/07853890.2017.1387927?journalCode=iann20">found</a> that people who combine both exercise and sauna baths have a substantially reduced risk of dying from <em>any</em> disease compared to exercise or sauna bathing alone. </p>
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<p>Taking saunas has also been <a href="https://www.researchgate.net/publication/6914269_Health_effects_and_risk_of_sauna_bathing">linked with an improvement</a> in the pain and symptoms associated with musculo-skeletal disorders such as osteoarthritis and rheumatoid arthritis. </p>
<p>Evidence from an <a href="http://online.liebertpub.com/doi/abs/10.1089/acm.2013.0466">experimental study</a> revealed that regular sauna bathing substantially improves the intensity of chronic-tension headaches. It has also been shown to reduce the incidence of common colds, and <a href="http://www.archives-pmr.org/article/0003-9993(89)90056-7/pdf">improve lung function and breathing</a> in patients with lung diseases such as asthma and chronic bronchitis. </p>
<h2>Hot stuff</h2>
<p>The same researchers from Bristol and Eastern Finland recently studied a population of 2,210 Finnish middle-aged men whose health was tracked for over a quarter of a century. This <a href="http://www.resmedjournal.com/article/S0954-6111(17)30357-8/abstract">showed</a> that men who enjoyed frequent saunas were less likely to develop pneumonia. Though there is uncertainty on how saunas reduce the risk of respiratory diseases, the theory is that the heat from sauna reduces congestion in the lungs and improves ventilation. There is also a theory that sauna reduces inflammation and oxidative stress, factors which are commonly implicated in the development of infection and most disease conditions.</p>
<p>Indeed, the evidence shows that sauna bathing has great promise beyond its use for pleasure and relaxation, including a protective effect on several disease conditions. </p>
<p>And there’s no better time to spend some time in your nearest sauna. As the weather gets colder, the risk of contracting common colds and developing respiratory diseases substantially increases. Blood pressure is also known to be generally higher in the winter, which increases the risk of strokes and heart attacks.</p>
<p>Sauna bathing is an enjoyable and relaxing activity, which could be giving you all sorts of benefits beneath your sweaty exterior. And while it doesn’t suit those with low blood pressure, or unstable hearts, taking regular saunas should be widely encouraged. If you can stand the heat, get in the sauna.</p><img src="https://counter.theconversation.com/content/87055/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Setor Kunutsor 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>They provide more than warmth.Setor Kunutsor, Research Fellow in Evidence Synthesis, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/710282017-01-16T14:21:19Z2017-01-16T14:21:19ZLess pain, more gain – improving health and fitness with minimal exercise<figure><img src="https://images.theconversation.com/files/152769/original/image-20170115-11800-m1chy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/335175395?size=medium_jpg">wavebreakmedia/Shutterstock.com</a></span></figcaption></figure><p>When it comes to exercise, if there was a way to get more health benefits by doing less, then it’s likely a lot of people would be interested. This is probably the reason that high-intensity interval training (HIIT) <a href="http://www.bbc.co.uk/news/magazine-37249021">gets a lot of attention</a>. HIIT can improve health and fitness, but with <a href="http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2011.224725/full">much less time spent exercising</a>. Much less time when compared with much lower intensity <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154075">aerobic exercise</a>, that is. </p>
<p>As new and exciting as HIIT might seem, it doesn’t challenge the fundamental assumption of sport science that if you do more exercise – regardless of what it is – you will get bigger improvements. </p>
<p>However, our <a href="http://journals.lww.com/acsm-msse/Abstract/publishahead/Effect_of_Number_of_Sprints_in_a_SIT_Session_on.97308.aspx">latest research</a> does challenge this assumption. We found that doing <em>fewer</em> high intensity sprints in a training session may actually enhance changes in cardiovascular fitness seen over several weeks of HIIT. And the lowest number of sprints that our study showed to be effective? Just two. </p>
<h2>VO₂max - a very important measure</h2>
<p>Prescribing exercise is a complicated business. Complicated in part because of the vast array of exercise programmes that are possible, but also because the “optimal” exercise programme is different for different people and depends on which aspect of health a person is looking to improve. For example, the optimal exercise programme to reduce blood pressure in someone who has hypertension may be very different from the optimal exercise programme to lower blood-sugar levels in somebody with type 2 diabetes. </p>
<p>For our study, we looked specifically at changes in cardiovascular fitness (termed “VO₂max”). Improving cardiovascular fitness is <a href="http://circ.ahajournals.org/content/134/24/e653.long">one of the most important things we can do for our health</a>. In fact, VO₂max may be a more important marker of long-term health than other risk factors, such as obesity and high blood pressure. </p>
<p>Because exercise is the only way to improve VO₂max, this knowledge places even more emphasis on the importance of performing regular exercise. Public health organisations recommend <a href="http://www.nhs.uk/Livewell/fitness/Pages/physical-activity-guidelines-for-adults.aspx">30 minutes of moderate exercise on most days of the week</a>. </p>
<p>Although this level of aerobic exercise is <a href="http://journals.lww.com/acsm-msse/Fulltext/2011/07000/Quantity_and_Quality_of_Exercise_for_Developing.26.aspx">enough to improve VO₂max</a>, the current understanding is that if you <a href="http://jamanetwork.com/journals/jama/fullarticle/1108370">exercise for longer</a> at the same intensity you reap more benefits. This is known as a “dose response”. </p>
<p>And if you exercise for a similar duration, then <a href="http://www.sciencedirect.com/science/article/pii/S0012369215527049">exercising at a higher intensity will also lead to greater improvements</a>. So doing more is considered to be better, as long as it’s done with regularity, of course.</p>
<h2>When more is less</h2>
<p>In our study we looked at a specific type of HIIT, which involves short bursts (20-30 seconds) of all-out (“maximal”) exercise interspersed with periods of low-intensity recovery. This is sometimes referred to as sprint interval training (SIT for short). We were interested in examining the dose response to SIT by looking at whether increasing the number of sprints in a training session would alter improvements in fitness levels (VO₂max) over the course of a training programme.</p>
<p>In our meta-analysis, we combined the data from 34 studies (418 participants in total) which looked at the effects of SIT (with varying numbers of sprints) on changes in VO₂max. Our findings showed that performing just two maximal 20-second sprints was very effective in improving VO₂max (<a href="https://www.researchgate.net/publication/305080058_Changes_in_aerobic_capacity_and_glycaemic_control_in_response_to_reduced-exertion_high-intensity_interval_training_REHIT_are_not_different_between_sedentary_men_and_women">around 10% improvement</a> when three sessions a week are performed over six weeks). But then, for every extra sprint completed, the improvement in fitness is actually reduced by around 5%. This may seem like a small amount, but it quickly adds up. By the time you’ve done seven sprints you’ve already lost 25% of the possible improvement. We do not currently have a biological explanation for this unexpected finding, but we are performing follow up studies to investigate some of the mechanisms involved. </p>
<p>One of the main implications of our finding is that the total time required to complete a HIIT exercise session that can benefit health and fitness can be reduced to as <a href="https://www.researchgate.net/publication/51833553_Towards_the_minimal_amount_of_exercise_for_improving_metabolic_health_Beneficial_effects_of_reduced-exertion_high-intensity_interval_training">little as ten minutes</a>. The low number of sprints needed may also make this form of HIIT much more tolerable for the general public. Given that few people meet the minimum exercise guideline, developing easier and time-efficient ways to exercise may prove fruitful. </p>
<p>The old adages “no pain, no gain” and “you have to burn it, to earn it” are certainly true; we have to exercise if we want to improve our fitness and reduce our risk of developing chronic disease. However, the amount of exercise you need to do may be less than you think.</p><img src="https://counter.theconversation.com/content/71028/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Metcalfe receives funding from The Diabetes Research and Wellness Foundation. </span></em></p><p class="fine-print"><em><span>Niels Vollaard receives funding from Diabetes UK and Nuffield Health. </span></em></p>New research on sprint interval exercise and cardiovascular fitness suggests doing less exercise may actually be better for us.Richard Metcalfe, Lecturer in Exercise and Health, Ulster UniversityNiels Vollaard, Lecturer, University of StirlingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/558742016-03-08T00:18:40Z2016-03-08T00:18:40ZExplainer: what happens during a heart attack and how is one diagnosed?<figure><img src="https://images.theconversation.com/files/114030/original/image-20160307-30476-k9sp4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most heart attacks aren't 'massive'.</span> <span class="attribution"><span class="source">from shutterstock.com</span></span></figcaption></figure><p>Most people usually link the phrase “heart attack” with “massive”; something you are indisputedly aware of. </p>
<p>Some are massive and, in these instances, it’s relatively easy to know if it is indeed a heart attack. Typically, there will have been crushing chest pain lasting more than a few minutes. One would hope this has led to an immediate call to 000 and a trip in an ambulance to hospital. </p>
<p>Often ambulance officers will have performed an electrocardiogram (ECG) and transmitted the results to the hospital, which will have selected and be ready with the appropriate treatment. In this case, the chest pain and the characteristic ECG changes are enough – those wiggly lines mean a lot to an experienced reader.</p>
<p>However, most heart attacks are not “massive”. In these instances, further tests are necessary and the diagnosis can become quite challenging. The pain may not be typical and the ECG may be normal or difficult to interpret.</p>
<h2>Different types of heart attacks</h2>
<p>“Heart attack” is not just one thing: there are <a href="http://www.health.harvard.edu/heart-health/our-concept-of-heart-attack-is-changing">five internationally recognised types</a>. </p>
<p>The one we think of first is when a plaque in a large coronary artery – consisting of cholesterol, cells and cellular debris that has built up over the years – suddenly cracks or erodes. This exposes the inside of the plaque to the blood flowing down the artery. The blood clots at this point, causing a thrombosis that narrows or blocks the artery.</p>
<p>If the artery is completely blocked, this is likely to cause death of heart muscle cells downstream and <a href="http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/cardiology/acute-myocardial-infarction/">myocardial infarction</a>, colloquially called a heart attack. </p>
<p>Two different kinds of heart attack are distinguished by the ECG changes – <a href="http://heartdisease.about.com/od/heartattack/g/STEMI.htm">STEMI</a> (ST segment elevation myocardial infarction) and NSTEMI (non-STEMI) – which may require different treatments. STEMI generally means the artery has blocked completely. If the artery is only partly narrowed and the downstream muscle causes pain but survives the syndrome, it is known as unstable angina. </p>
<p>Cardiologists prefer the term acute coronary syndrome (ACS) to describe the spectrum of consequences of short-term lack of blood and oxygen to the heart muscle. As this is a spectrum, it is perhaps not surprising that it has been difficult to come up with a dichotomous separation of “heart attack” or “no heart attack”.</p>
<h2>Heart attack or no heart attack</h2>
<p>Medical advances over the decades have provided some clarity. But this has also caused a rethink among those trying to define the various levels of heart attack, both for management decisions and for practical purposes such as insurance.</p>
<p>For many years, diagnosis has depended on measurements of the changes in levels of enzymes released by dying heart muscle cells. These rise in the blood some hours after the initial event peaks and then gradually fall, with different enzymes following a different time course. </p>
<p>Until the 1990s, the enzymes that were used for this purpose included a panel of up to three. Each followed a vastly different time course. However, they are not specific to heart muscle cells and a rise could be due to many other conditions. </p>
<p>Testing was refined with the development of a muscle-specific enzyme test for <a href="http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/8336">creatinine kinase</a> (CK). But the search was on for a test that would both identify loss of heart muscle by levels rising earlier and be more specific to the heart.</p>
<p>Measurement of troponin was the next big advance <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100278/">in the mid-1990s</a> and revolutionised the classification of heart attacks. Troponin is released from muscle one to three hours after an artery is blocked and may stay high for up to 14 days. It is more specific to heart muscle than previous enzyme tests. </p>
<p>Over the past decade, the test has been refined to be more and more sensitive. But each test needs its own threshold level for an abnormal result, so an absolute result of a test in one laboratory may not be comparable to that of another. </p>
<p>Nevertheless, the availability and refinement of the troponin test used properly has introduced a level of certainty in the diagnosis of acute heart syndromes that was not previously available. Myocardial infarction can be ruled out earlier. Small infarcts can be identified that would previously have been missed. </p>
<h2>The problem with measuring troponin</h2>
<p>Troponin measurements introduced their own problems too. During the late 1990s, it seemed that a sizable proportion of people presenting to emergency departments had rising troponin levels but no other signs of heart attack. The tests were picking up <a href="http://www.nytimes.com/1996/10/31/us/new-tests-detect-mild-heart-attacks-that-are-now-often-missed.html">smaller and smaller amounts</a> of heart muscle damage. </p>
<p>So somebody presenting in the 1990s would get a different diagnosis to another person with the same problem presenting this decade in the high-sensitivity troponin era. </p>
<p>Clinicians are becoming aware of a number of situations where <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3212425/">false positives</a> can occur. This may result from damage to the heart from trauma, frequent defibrillator shocks, heart failure, disease of the aorta, pulmonary embolism, kidney failure, stroke, various drugs and critical illnesses such as burns and sepsis. </p>
<p>Troponin can also miss heart attacks if used alone, or the blood is taken outside the window when levels are elevated, or the laboratory uses an insensitive troponin test.</p>
<p>The Australian national guidelines for diagnosing myocardial infarction are due for release in the next few months by the National Heart Foundation and the Cardiac Society of Australia and New Zealand and will consider these problems. In the meantime, the <a href="http://circ.ahajournals.org/content/126/16/2020">third universal definition of myocardial infarction</a> is the internationally recognised and accepted guideline.</p><img src="https://counter.theconversation.com/content/55874/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Garry Jennings receives funding from the National Health and Medical Research Council</span></em></p>Most heart attacks are not “massive”. In these instances, further tests are necessary and the diagnosis can then become quite challenging.Garry Jennings, Chief Executive Officer at National Heart Foundation of Australia; Senior Fellow, Baker Heart and Diabetes InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/478952015-12-10T11:17:52Z2015-12-10T11:17:52ZWhen is an aspirin a day to prevent heart attacks too risky?<figure><img src="https://images.theconversation.com/files/102904/original/image-20151123-18233-a5dyg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">What's the harm?</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic.mhtml?id=117314986&src=id">Aspirin via www.shutterstock.com.</a></span></figcaption></figure><p>We’ve known for a long time that aspirin can help prevent damage from a heart attack or a stroke if taken during one of those events. In fact, you might have seen ads about how aspirin can be lifesaving during a heart attack.</p>
<p>Research backs that up. For people who have already experienced a heart attack or stroke, a daily aspirin regimen can <a href="http://circ.ahajournals.org/content/130/25/e344">actually prevent</a> future <a href="http://journal.publications.chestnet.org/article.aspx?articleID=1159438">heart attacks</a> and strokes.</p>
<p>But, as helpful as aspirin is to prevent recurrent heart attacks or strokes (this is called secondary prevention), a daily aspirin has long been controversial to prevent a first heart attack or stroke (this is called primary prevention). </p>
<p>To use aspirin for primary prevention, doctors are supposed to assess a patient’s risk of a first heart attack or stroke and decide when benefits of aspirin outweigh risks. But new draft guidelines for aspirin use have created confusion about who, exactly, should actually take aspirin. </p>
<h2>What do the new draft guidelines say about aspirin?</h2>
<p>The <a href="http://www.uspreventiveservicestaskforce.org/Page/Document/draft-recommendation-statement/aspirin-to-prevent-cardiovascular-disease-and-cancer">new draft guidelines</a> from the United States Preventative Services Task Force recommend adults between the ages of 50-59 take aspirin if they have at least a 10% 10-year risk of having a heart attack or stroke as measured by a <a href="http://www.cvriskcalculator.com/">risk calculator </a>.</p>
<p>For people 60-69, the task force says there is less benefit compared to for those ages 50-59, but that aspirin should still be used as long as there is a low risk of bleeding as a side effect.</p>
<p>But for patients younger than 50 or older than 70, the task force decided there was not enough evidence to make a recommendation about using aspirin. This is a major departure from the 2009 recommendation, which suggested use in all adults between the ages of 45-79 with an elevated risk of a heart attack or stroke.</p>
<p>This change happened in part because of a push to make medical guidelines strictly evidence-based. Right now, there are no randomized trials comparing aspirin to placebo in adults older than 70 or younger than 50. Without evidence, you can’t have evidence-based recommendations.</p>
<p>Basing guidelines strictly on evidence makes sense, but clinical trials are rarely perfect, and recommendations on how to use drugs need to make sense to primary care providers in order to avoid confusion.</p>
<h2>What do the data say about aspirin for primary prevention?</h2>
<p>Early trials that treated patients with aspirin during a heart attack or stroke found they were more likely to survive. But these trials <a href="http://circ.ahajournals.org/content/130/25/e344">also found</a> that leaving patients on aspirin for months and years afterwards reduced future heart attacks and strokes. </p>
<p>For every 100 patients who’ve had a heart attack or stroke and stay on a daily aspirin, five recurrent heart attacks or strokes are prevented in the next year. While there is a small risk of serious bleeding with aspirin (mostly stomach bleeding, but also bleeding in the brain), fewer than one in 100 patients experience this. Therefore, everyone agrees that the benefits of aspirin outweigh the risks for people who have had a heart attack or stroke.</p>
<p>But for patients with no history of a heart attack or stroke, the <a href="http://dx.doi.org/10.1016/S0140-6736(09)60503-1">data say</a> that the risk of serious bleeds and the benefit of reducing heart attacks and strokes are about equal for a population of middle-aged and older adults. </p>
<p>According to the new calculations in the task force guidelines, for every 100 men 55-60 years old with an <a href="http://www.cvriskcalculator.com">average risk</a> of a first heart attack or stroke of 1% per year, starting a daily aspirin would have a <em>lifetime</em> effect of avoiding about two heart attacks and one stroke among those 100 men, but causing about three serious stomach bleeds and about one hemorrhagic stroke. </p>
<h2>What do the new guidelines mean for you?</h2>
<p>The draft guidelines from the Preventative Services Task Force might not offer a lot of clear yes’s and no’s about who should and shouldn’t take aspirin for primary prevention. And guidelines from other groups offer differing advice. </p>
<p>Guidelines from <a href="http://www.heart.org/HEARTORG/Conditions/HeartAttack/PreventionTreatmentofHeartAttack/Aspirin-and-Heart-Disease_UCM_321714_Article.jsp">The American Heart Association</a>, <a href="http://content.onlinejacc.org/article.aspx?articleid=1889061">American College of Cardiology</a> and <a href="http://care.diabetesjournals.org/content/33/6/1395.full">American Diabetes Association</a> all endorse aspirin for primary prevention in certain higher-risk patients. However, the Food and Drug Administration <a href="http://www.bmj.com/content/348/bmj.g3168">denied a petition</a> from the aspirin manufacturer Bayer Inc for wording on their label that said aspirin could prevent heart attacks and strokes for people who had never had them.</p>
<p>And the <a href="http://www.escardio.org/The-ESC/Press-Office/Press-releases/Last-5-years/Aspirin-still-overprescribed-for-stroke-prevention-in-AF">European Society of Cardiology</a> does not endorse aspirin for primary prevention for any patient – even those at high risk.</p>
<p>But, the “over-the-counter” availability of aspirin means that Americans, many Europeans and potential patients all over the world can decide for themselves whether or not to take aspirin. And many are deciding to do so. A national survey that <a href="http://www.ajpmonline.org/article/S0749-3797(14/)00661-8/fulltext">we published in 2015</a> showed that nearly half of all US adults without CVD indicated that they “regularly” used aspirin as a preventive therapy. </p>
<p>So what should patients do? If you are over the age of 40 and don’t have a history of cardiovascular disease, check your predicted <a href="http://www.cvriskcalculator.com/">10-year risk of CVD</a>. </p>
<p>If your individual risk is greater than 10%, talk to your doctor about taking aspirin. Patients who don’t have a risk of bleeding could be considered good candidates for therapy, but they should understand that the odds of a serious bleed are about the same as the odds of preventing a heart attack or stroke. Not all patients will want to take the trade-off. </p>
<p>For patients who are under 70 with a CVD risk of less than 10%, aspirin therapy should generally be avoided. </p>
<p>While it is widely believed that these new task force recommendations will cut down on how many people go on an aspirin regimen in the US, that remains to be seen. It depends whether busy primary care providers read and agree with the guidelines, and then translate them into clinical practice.</p><img src="https://counter.theconversation.com/content/47895/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Craig Williams 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>New draft guidelines for using aspirin to prevent heart attacks have created confusion about who, exactly, should actually take it.Craig Williams, Professor of Pharmacy, Oregon State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/317282014-09-18T20:26:04Z2014-09-18T20:26:04ZMild high blood pressure: are we treating too many people?<figure><img src="https://images.theconversation.com/files/59405/original/vmvtvj94-1411023028.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's no proof blood pressure-lowering drugs prevent heart attacks in people with mild hypertension – but they could.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/easy-pics/8287163339">The Clear Communication.../Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>An <a href="http://www.bmj.com/content/349/bmj.g5432">article</a> in this week’s issue of the British Medical Journal calls into question a common practice: treatment of mild high blood pressure. </p>
<p>The authors argue that lowering the drug threshold for high blood pressure has exposed millions of low-risk people around the world to drug treatment of uncertain benefit, at huge cost to the health system: $32 billion annually in the United States alone. </p>
<p>It’s a provocative but thoughtful take on an important issue. But it doesn’t mean you should ditch your blood pressure-lowering drugs. Let’s consider the evidence and what it all means for people with mild high blood pressure. </p>
<p>But first, what is blood pressure, and how high is too high?</p>
<h2>Hypertension</h2>
<p>Consistently high blood pressure is called hypertension, and medicines used to bring blood pressure down are called anti-hypertensives. </p>
<p>There’s no doubt that hypertension is a <a href="http://www.ncbi.nlm.nih.gov/pubmed/18456100">major risk factor</a> for diseases like heart attacks and stroke. And there’s <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001841.pub2/abstract">good evidence</a> that anti-hypertensive medicines do work – they not only reduce blood pressure but (more importantly) many also reduce the occurrence of strokes, heart attacks and sometimes death.</p>
<p>Like the air pressure in a tyre, blood pressure can be measured numerically. Unlike a tyre, blood pressure swerves up and down with every beat and relaxation of the heart. The two numbers in a blood pressure reading indicate the maximum and minimum levels it veers between with every beat. </p>
<p>While a textbook “normal” blood pressure would be about 120/80, readings vary a lot between people, and even change from minute to minute in an individual. The fickle nature of blood pressure means we needs lots of readings (preferably during normal life rather than in a doctor’s office) to get a reliable average in a given person.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/59410/original/n2nyt6kh-1411023833.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/59410/original/n2nyt6kh-1411023833.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/59410/original/n2nyt6kh-1411023833.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/59410/original/n2nyt6kh-1411023833.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/59410/original/n2nyt6kh-1411023833.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/59410/original/n2nyt6kh-1411023833.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/59410/original/n2nyt6kh-1411023833.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">Anti-hypertensives have clear benefits for some people with high blood pressure.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/21560098@N06/12115824515">Nina Matthews Photography/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Exactly what blood pressure range is acceptably normal is surprisingly hard to answer. Thresholds for high blood pressure used to be more lenient, but for some years now several international guidelines (including <a href="http://www.heartfoundation.org.au/SiteCollectionDocuments/HypertensionGuidelines2008to2010Update.pdf">Australia’s</a>) have used above 140/90 as the defining threshold for hypertension.</p>
<h2>The controversy</h2>
<p>We’re confident that several anti-hypertensive medicines <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001841.pub2/abstract">reduce risk</a> for people with moderate or severe hypertension (above 160/100), and even for people with normal blood pressure who are at <a href="http://www.nejm.org/doi/full/10.1056/NEJM200001203420301">high risk</a> because of a past heart attack. </p>
<p>What’s controversial is whether the medicines benefit people with mild hypertension (140-159/90-99) who’ve not had a heart attack or a stroke. This category includes <a href="http://www.aihw.gov.au/high-blood-pressure/">a lot of people</a> – perhaps over a million Australians.</p>
<p>Central to the <a href="http://www.bmj.com/content/349/bmj.g5432">new article’s</a> argument is that, when all the available results of trials of anti-hypertensives in people with mild hypertension are <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006742.pub2/abstract">brought together</a>, they don’t prove that such treatments save lives or prevent heart attacks or strokes. </p>
<p>Because most previous anti-hypertensive trials studied people with higher average blood pressures, it was hard for analysts to find data on treatment of people with only mild hypertension.</p>
<p>But absence of proof of benefit doesn’t mean we’re sure that treating mild hypertension is useless. It just means that we don’t know. </p>
<p>In fact <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006742.pub2/abstract">the data</a> hinted, imprecisely, at possible reductions in death and strokes from treating mild hypertension. Though this impression was not “statistically significant” – it could quite plausibly have been a statistical illusion. Such chance findings happen easily when you measure an uncommon outcome in too few people.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/59408/original/gbxbvtqk-1411023637.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/59408/original/gbxbvtqk-1411023637.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/59408/original/gbxbvtqk-1411023637.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/59408/original/gbxbvtqk-1411023637.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/59408/original/gbxbvtqk-1411023637.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/59408/original/gbxbvtqk-1411023637.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/59408/original/gbxbvtqk-1411023637.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The guidelines for when to prescribe anti-hypertensives are contradictory.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/63837019@N03/9510643032">World Granny/</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Such uncertainty is a breeding ground for controversy. The sceptical authors of the <a href="http://www.bmj.com/content/349/bmj.g5432">new article</a> take the view that, as treating mild hypertension is unproven and costly, and as the medicines can cause side effects, we should be much more cautious about prescribing them in mild hypertension. </p>
<p>On the other hand, advocates of treatment of mild hypertension take the view that too few people with mild hypertension have been studied, for too short a time, to rule out a benefit. Given the proven benefits of anti-hypertensives in other groups of people, they say it may be <a href="http://www.ncbi.nlm.nih.gov/pubmed/23152161">unethical</a> to study this further, and we should <a href="http://www.forbes.com/sites/peterlipson/2013/05/29/are-we-over-treating-high-blood-pressure/">continue treating</a> those with mild hypertension.</p>
<p>It’s a very similar debate to the <a href="https://theconversation.com/worried-about-taking-statins-heres-what-you-need-to-know-19877">recent furore</a> around prescribing of statins (cholesterol-lowering pills). Statins are <a href="http://www.ncbi.nlm.nih.gov/pubmed/15249352">life-savers</a> in patients at high risk, but do they save lives in people at low risk? Some say <a href="http://www.ncbi.nlm.nih.gov/pubmed/21989464">yes</a>, some say <a href="http://www.ncbi.nlm.nih.gov/pubmed/20585067">no</a>. While battles erupt in journals and <a href="http://theconversation.com/viewing-catalysts-cholesterol-programs-through-the-sceptometer-19817">other media</a>, doctors and their patients are left confused.</p>
<p>Adding to the confusion are the inconsistent guidelines which doctors are encouraged to follow. Faced with a middle-aged person with blood pressure of 155/95 and with no other risk factors, one major Australian guideline <a href="http://www.heartfoundation.org.au/SiteCollectionDocuments/HypertensionGuidelines2008to2010Update.pdf">encourages us GPs</a> to prescribe anti-hypertensives, while another <a href="http://strokefoundation.com.au/site/media/AbsoluteCVD_GL_webready.pdf">dissuades us</a> from doing so. (Both guidelines are endorsed by Australia’s <a href="http://www.heartfoundation.org.au">Heart Foundation</a>.)</p>
<h2>What we can all do</h2>
<p>First, all of us can try to have a healthy lifestyle: exercising, and avoiding smoking and excessive alcohol and salt. These measures lower blood pressure, but are also good for all of us regardless of our blood pressure.</p>
<p>Second, if you have hypertension, try to engage with your doctor in <a href="https://www.mja.com.au/journal/2014/201/1/shared-decision-making-what-do-clinicians-need-know-and-why-should-they-bother">shared decision-making</a>. Hopefully your doctor will acknowledge what we do and don’t know on this topic.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/59412/original/5zrbdvbs-1411024007.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/59412/original/5zrbdvbs-1411024007.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/59412/original/5zrbdvbs-1411024007.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/59412/original/5zrbdvbs-1411024007.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/59412/original/5zrbdvbs-1411024007.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/59412/original/5zrbdvbs-1411024007.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/59412/original/5zrbdvbs-1411024007.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&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">Many of us should cut down on salt anyway.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-77804164/stock-photo-golden-french-fries-potatoes-ready-to-be-eaten.html?src=pp-same_artist-78030421-ibbM2BQ3dnk8cwTDoAlU8g-1">ilolab/Shutterstock</a></span>
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<p>With your doctor, consider how much risk you are at of heart attacks or strokes. If you’ve already had one of these events, then you are at very high risk, and anti-hypertensives will likely be recommended with confidence. </p>
<p>Otherwise, online <a href="http://www.cvdcheck.org.au/">tools</a> are <a href="http://www.qrisk.org/">available</a> to <a href="http://bestsciencemedicine.com/chd/calc2.html">estimate</a> your “absolute risk”. These tools are based not just on your blood pressure, but also other important factors like age, gender, smoking, diabetes and cholesterol. Mild hypertension alone may not put you at great risk, but it may be more significant when combined with other problems.</p>
<p>If medicines for mild high blood pressure do offer some (as yet theoretical) protection, then they are more likely to do so the higher your risk is. If, for example, a treatment prevented a quarter of some possible nasty events, but your risk of such an event was only 4% over five years, then your chance of the treatment preventing that event is only 1% over those five years. </p>
<p>Personally, I would opt for treatment of mild hypertension if my overall risk was high, but probably not if it was low. But you might make a different decision to me. And that’s OK – we all have different values and preferences.</p>
<p>Finally, there are things that can be done at a population level that can help blood pressure and risk. Some authors suggest worrying less about doctor visits and measurements, and instead just putting everyone over the age of 55 onto a “<a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC162259/">polypill</a>” containing several low-dose medicines. But this strategy is unproven, and involves an awful lot of pill-popping.</p>
<p>Less radical, and hopefully more acceptable, are policy measures to reduce the health impacts of smoking, alcohol and salt, and to encourage physical activity. Measures like reducing societal inequality, encouraging active transportation and ensuring access to healthy foods <a href="http://www.who.int/social_determinants/thecommission/finalreport/key_concepts/en/">might</a> do more good than doctors visits and pills.</p><img src="https://counter.theconversation.com/content/31728/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brett Montgomery divides his working life between academic and clinical general practice. In his clinical work he, like most GPs, frequently treats patients who have high blood pressure.</span></em></p>An article in this week’s issue of the British Medical Journal calls into question a common practice: treatment of mild high blood pressure. The authors argue that lowering the drug threshold for high…Brett Montgomery, Associate Professor in General Practice, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/207862013-11-27T01:01:40Z2013-11-27T01:01:40ZSalt in soluble drugs increases risk of heart attacks and strokes<figure><img src="https://images.theconversation.com/files/36226/original/njt5qbzz-1385512945.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Soluble versions of common medications such as aspirin may increase risk of cardiovascular problems. </span> <span class="attribution"><span class="source">Pierre Guinoiseau</span></span></figcaption></figure><p>The salt found in common effervescent and soluble drugs may be exposing consumers to an increased risk of heart problems, according to <a href="http://www.bmj.com/content/347/bmj.f6954">a study published in the BMJ</a> today. </p>
<p>The study found it’s possible to exceeded the recommended daily intake of salt of 2.4 grams just by consuming the maximum daily dose of some drugs.</p>
<p>Associate Professor in Pharmacology at Murdoch University, Ian Mullaney said salt is an essential ingredient in modern medicines. </p>
<p>“The drugs have properties that make them insoluble or don’t combine very well, and salt has been used since in the early days of medicine manufacture just to combine the ingredients of the medicine to make them soluble,” he said. </p>
<p>But <a href="https://theconversation.com/sodium-study-should-be-taken-with-a-large-pinch-of-salt-1051">excessive salt consumption</a> is harmful to heart health.</p>
<p>Professor of preventative cardiology & internal medicine at Griffith University, Ian Hamilton-Craig said excessive salt intake could raise blood pressure, which increases the risk of heart disease and stroke.</p>
<p>While tablets that easily dissolve in water are a convenient option for many consumers their high salt content is a hidden drawback.</p>
<p>The study authors tracked over 1.2 million people for 13 years. They found people taking these medicines had a 16% increased risk of heart attack, stroke or vascular death than those taking the non-sodium versions of the same drugs. </p>
<p>People taking these high-salt medicines were also seven times more likely to develop high blood pressure, a <a href="http://www.heartfoundation.org.au/your-heart/cardiovascular-conditions/Pages/blood-pressure.aspx">condition</a> affecting over 3.5 million Australians. </p>
<p>Mullaney pointed out that there were low-salt and high-salt varieties for common medications, so people concerned about their health had a choice. </p>
<p>“This is especially important for people with high blood pressure or heart failure, for whom low-salt varieties should be chosen,” Hamilton-Craig said.</p>
<p>The study authors have called for drug companies to list the salt content of medicines and for people taking high-salt medications to visit their doctor regularly.</p><img src="https://counter.theconversation.com/content/20786/count.gif" alt="The Conversation" width="1" height="1" />
The salt found in common effervescent and soluble drugs may be exposing consumers to an increased risk of heart problems, according to a study published in the BMJ today. The study found it’s possible…Aneeka Simonis, Editor, The ConversationRachel Worsley, EditorLicensed as Creative Commons – attribution, no derivatives.