tag:theconversation.com,2011:/us/topics/hydrotherapy-34353/articleshydrotherapy – The Conversation2018-03-22T11:29:39Ztag:theconversation.com,2011:article/929782018-03-22T11:29:39Z2018-03-22T11:29:39ZThe bottled water industry’s healthy origins<figure><img src="https://images.theconversation.com/files/211540/original/file-20180322-165564-d53tjd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Evians on Lake Geneva was originally a spa town.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/view-french-town-evians-over-lake-294342134?src=tnQvOOL036jM00qlczwuBg-1-15">shutterstock.com</a></span></figcaption></figure><p>Huge outcry ensued from my <a href="https://theconversation.com/how-brexit-could-drain-britains-bottled-mineral-water-industry-dry-91859">recent article</a> about how Brexit would hurt Britain’s bottled water industry. The outcry wasn’t to do with Brexit. Instead, it was over the very existence of a bottled water business. </p>
<p>There were environmental concerns relating to the huge amount of plastic that the industry involves, not to mention the fuel used in transporting the bottles. There were also suggestions that the industry is a “scam” in countries where people can access perfectly good water from the tap.</p>
<p>So who had the great idea of selling something which, in principle, is so cheap and accessible? Some varieties can cost <a href="https://blingh2o.com/shop-the-collection?olsPage=products%2Fthe-ten-thousand&page=1&sortOption=descend_by_price">as much as £2,000 a bottle</a>.</p>
<p>The origins of bottled water have to be traced back to when spas had a resurgence in popularity in Europe and its colonies in the 18th and 19th centuries. It was a time when tap water was unsafe to drink and, although people were unaware of this, the groundwork was laid for many of the household names in the bottled water industry today.</p>
<h2>Taking the waters</h2>
<p>A change in social, cultural and medicinal practices resurrected the Greco-Roman tradition of “taking the waters” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2557450/pdf/medhistsuppl00037-0037.pdf">for health purposes</a>. Thanks to the development and popularisation of hydrotherapy by famous physicians such as <a href="http://nrl.northumbria.ac.uk/582/1/steward_The%20culture%20of%20water%20cure%20in%20nineteenthcentury%20Austria.pdf">Priessnitz and Kneipp</a>, and the special properties of waters found in certain locations, such as their chemical composition or their temperature, formerly derelict spas flourished again and new ones were built. </p>
<p>Spa towns such as Vichy, Evian and Vittel in France, Bath and Buxton in England, San Pellegrino in Italy, Caldes de Malavella in Catalonia, and Carlsbad (Karlovy Vary) in what is now the Czech Republic became the hotspots. Wealthy people flocked to them to relax, socialise and seek treatment for a variety of ailments.</p>
<p>The period when spa culture flourished in the West coincided with the height of the Industrial Revolution, when cities became crowded and <a href="https://www.theguardian.com/news/datablog/2013/mar/15/john-snow-cholera-map">waterborne diseases were commonplace</a>. Epidemics such as cholera or typhoid fever ravaged cities and caused serious health conditions, which often led to hundreds of deaths due to the drinking of contaminated water. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/211543/original/file-20180322-54884-1iggcuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/211543/original/file-20180322-54884-1iggcuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/211543/original/file-20180322-54884-1iggcuk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/211543/original/file-20180322-54884-1iggcuk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/211543/original/file-20180322-54884-1iggcuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/211543/original/file-20180322-54884-1iggcuk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/211543/original/file-20180322-54884-1iggcuk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&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">Cholera was a major problem but its causes were unknown.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:London_Board_of_Health_searching_the_city_for_cholera_Wellcome_V0010896.jpg">Wellcome Library no. 1998i</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>It is therefore not surprising that going to a spa town – usually located in the countryside and with water originating from unpolluted sources – dramatically reduced the chances of getting ill and helped recovery from existing illnesses. But treatments were expensive, as they were lengthy, lasting several weeks and in some cases months. </p>
<h2>The bottling business</h2>
<p>Such lengthy treatments were not available to everyone, not only because of the cost, but also due to the necessary time commitment. This meant that busy people couldn’t always finish their treatments. Consequently, some asked bath houses if they could subscribe to a periodic delivery of water from the spa for a fee in order to continue the treatment throughout the year. And those who could not afford to go to the spa also wanted to have access to its water. </p>
<p>Even though some bath house owners were reluctant at first, many agreed and started shipping water to cities. Initially it was at a high cost, as water is very heavy and difficult to transport. Labels and watermarks on bottles developed in response to the illegal trade that sprung up where fake bottled water was sold to those who could not afford to buy the real deal.</p>
<p>With the expansion of the railway and the general improvement of communication systems, transportation costs became progressively lower and more people were able to afford mineral water in cities. This in turn increased its production and sale. It led to the start of businesses which sold water from sources not linked to spas, and therefore not necessarily marketed as medicinal; they just sold water which was cleaner than publicly sourced water during a time when epidemics were rife. </p>
<p>The business boomed until urban and domestic water sanitation methods improved, especially with the spread of chlorination techniques during the first decades of the 20th century and the discovery of how illnesses could be identified and treated. Both advances had an important impact on the spa water industry and the bottled water business. Many struggled or disappeared altogether. </p>
<p>But recent years have seen the resurgence of the industry, led by technological and lifestyle changes. The brands and tradition were already there, so with some <a href="https://theconversation.com/bottled-water-is-the-marketing-trick-of-the-century-25842">effective marketing</a> and good distribution networks, bottled water has become popular again. But that is a <a href="https://theconversation.com/why-sales-of-bottled-water-overtaking-soft-drinks-is-nothing-to-celebrate-41695">different story</a>.</p><img src="https://counter.theconversation.com/content/92978/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexandre Nobajas has received funding from the Agency for Management of University and Research Grants, Catalan Government. </span></em></p>Some of the biggest names in the bottled water industry were originally spa towns that wealthy Europeans escaped to during the industrial revolution.Alexandre Nobajas, Lecturer in Human Geography and GIS, Keele UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/895132018-01-01T14:37:26Z2018-01-01T14:37:26ZIs a cold water swim good for you, or more likely to send you to the bottom?<p>There are people who will tell you that a dip in cold water is not just exhilarating and enlivening, but good for you. They have not, they will tell you, had a cold for years. In many nations there is a cultural tradition of cold water dips – whether that’s a swim on special occasions such as Boxing Day or New Year’s Day <a href="http://gafirs.org.uk/new-years-swim/">as in the UK</a>, or as part of a routine of alternating hot saunas and cold baths perceived to have health benefits, such as in Japan, Germany, Russia and <a href="http://cphpost.dk/news/culture/a-celebration-of-ice-cold-water.html">Scandinavia</a>. </p>
<p>But cold water immersion is a doubled-edged sword – and there is another group, often including those working in search and rescue, who will warn of the dangers posed by cold water. On average, <a href="http://www.rlss.org.uk/water-safety/drowning-prevention-week/">someone drowns every 20 hours in the UK</a> – and the Christmas holiday period is a particularly a bad time of year for drinking and drowning. </p>
<p>There are centuries of references to the dangers posed by cold water: Herodotus, describing the ill-fated sea expedition of the Persian general <a href="https://www.britannica.com/biography/Mardonius">Mardonius</a>, wrote in 450BC that “those who could not swim perished from that cause, others from the cold”. In December 1790, James Currie, a physician, stood unable to help as the crew of a stranded American sailing ship fell into the cold sea and drowned. Currie was so affected he went on to undertake the first recorded experiments on the effects of cold water immersion on the human body.</p>
<p>Similarly, claims for the health benefits of cold water, in spa or sea, also boast a long heritage: Hippocrates’ <a href="http://www.greekmedicine.net/therapies/The_Water_Cure.html">water therapy</a> was designed to allay “lassitude” (physical or mental weariness), while Thomas Jefferson claimed that 60 years of daily cold foot baths every morning had “maintained his good health”. By 1750, there was much published writing that recommended sea swimming for the treatment of a range of diseases, with winter considered the best time to engage in the activity. Sea bathing reached a peak in popularity in the late 18th century and led to the establishment of many of the seaside towns and resorts we visit today. Recently there has been a significant increase in the popularity of “wild” swimming in lakes, rivers and streams, or <a href="https://www.internationaliceswimming.com/">marathon swimming</a>.</p>
<p>The question is: what does the science say as to whether a freezing dip will “kill or cure”? We <a href="http://onlinelibrary.wiley.com/doi/10.1113/EP086283/full">looked at the evidence</a>.</p>
<h2>A quick way to die</h2>
<p>There is no doubt that the physiological responses to immersion in cold water are dangerous, and are precursors to sudden heart attack, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1982576/">the loss of capacity to swim</a>, hypothermia and drowning. Hypothermia has traditionally been regarded as the major threat from being in cold water, largely thanks to the fate of victims of the Titanic disaster and, later, the tens of thousands of mariners’ deaths during World War II – some 30,000 of 45,000 Royal Navy deaths occurred when sailors escaping their sinking ships were trying to survive in the sea. </p>
<p>However an increasing collection of statistical, experimental and anecdotal evidence has meant that focus has shifted to <a href="https://www.ncbi.nlm.nih.gov/pubmed/2691172">the “cold shock” response</a>: the initial cardio-respiratory response evoked by the sudden cooling of the skin. This places a strain on the heart, and the sudden loss of control over breathing leading to gasping means that the likelihood of breathing in water, even the small volume of water necessary to drown, is significantly increased.</p>
<p>For example, the cold shock response peaks in water between 10-15°C, and the initial one to two-litre gasp of breath prompted by cold water immersion is usually larger than the lethal dose of salt water for drowning. The cold shock response explains why about 60% of those who die in cold water do so in the first minutes, not in the much longer period required for hypothermia to set in.</p>
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<h2>Invigorating</h2>
<p>On the plus side, there is no doubt that a cold dip stimulates the body. The release of stress hormones gives that energised feeling of being really “alive”. The cold and pressure on the body from immersion in water can also act to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3766664/">reduce swelling and combat inflammation</a>. The use of tcold water therapy to <a href="https://doi.org/10.1002/14651858.CD008262.pub2">aid recovery after exercise</a> has been reported to have differing levels of efficacy depending on the exercise and treatment used.</p>
<p>Staying with the theme of inflammation, there is an expanding body of evidence that links inflammation with physical and mental health. Becoming adapted to cold water through repeated immersions can theoretically <a href="https://www.ncbi.nlm.nih.gov/pubmed/10735978">reduce the body’s inflammatory response</a>. This reduction of inflammation explains why repeated cold water immersion may be therapeutic for other conditions which may have an inflammatory component. For example there is recent research to suggest that <a href="https://www.ncbi.nlm.nih.gov/pubmed/26711676">depression</a> is a response to inflammation in the body. </p>
<p>There is also evidence that adapting the body to cold water enhances the body’s ability to adapt to other, apparently unrelated stresses. For example, there is evidence that short immersions in cold water improves the body’s <a href="https://www.ncbi.nlm.nih.gov/pubmed/20643773">response to high altitude stress</a>. Having become adapted to cope with one, the body is also better at coping with the other.</p>
<p>Finally, that old chestnut about cold water baths being a defence against the common cold: when it comes to the benefits to the immune system of a freezing swim, the jury is still out. Some <a href="https://www.ncbi.nlm.nih.gov/pubmed/8925815">laboratory studies</a> have reported improved markers of immune function, but the clinical significance of these findings is uncertain. </p>
<p>For example, upper respiratory tract infection is often used as a useful measure of immune system functioning: open, cold water swimmers have been found to have fewer infections than their non-swimming partners, but <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4580837/">no fewer infections than indoor swimmers</a>. And herein lies one of the problems with the “benefits” side of the cold water debate: the properly controlled experiments that isolate cold water immersions from socialising, exercise, getting fitter, taking exercise in nature (so-called “green” therapy) and other activity that add complicating variables simply haven’t been done.</p>
<p>So, on balance the evidence is that cold water has a somewhat greater potential to “kill” than to “cure”. However, you can still enjoy and be invigorated by your festive dip, but go in slowly, with a friend, at a supervised event – and if you can wear a fancy dress costume that incorporates a wet suit, no one will blame you.</p><img src="https://counter.theconversation.com/content/89513/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mike Tipton 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>Cold water drowning kills many people every year. But can it also provide curative benefits? We asked an expert.Mike Tipton, Professor of human and applied Physiology, University of PortsmouthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/685832016-12-25T20:41:33Z2016-12-25T20:41:33ZHealth Check: why swimming in the sea is good for you<figure><img src="https://images.theconversation.com/files/148990/original/image-20161207-25753-83md7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bathing in the Dead Sea has long been used to treat psoriasis.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/60584010@N00/23932671816/in/photolist-CsRcwG-RDwB-5smym4-8BNdv2-ksJ1KP-8BNbvP-8BR3h3-cGmfK-7ASfpK-7AW4cJ-5DMQqa-9m711y-qFUNWS-7DXhCj-9m6ZZE-4f5vJq-eYY2H-eYYdK-eYY8j-8BRiM1-3fHwvx-fMgBzw-eYYax-9m3Wez-hd1bJw-4f5ffj-8BRiCN-7ASfNp-8BR3qh-qUe8SN-eYYcv-eYYhr-CnS3KM-gEMVY-8BNcti-daHumF-8BNbPe-7ASfVV-8BRiTJ-ftZjN6-4hqeHz-8BNcZR-34vFX-9m3Wfi-bZ3Hp-eYXX2-fTdDAF-8BMVV8-8BRjh9-3ZWkwx">leiris202/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>If you live near the sea, make frequent trips to the beach, or are planning an island holiday this summer, chances are you’re getting more out of it than just enjoyment. It has long been thought sea frolicking has many health benefits.</p>
<p>Historically, doctors would <a href="https://www.washingtonpost.com/news/wonk/wp/2016/07/03/the-weird-origins-of-going-to-the-beach/?utm_term=.c57b0fb7c182">recommend their patients go to the seaside</a> to improve various ills. They would actually issue prescriptions detailing exactly how long, how often and under what conditions their patients were to be in the water. </p>
<p>Using <a href="https://en.wikipedia.org/wiki/Thalassotherapy">seawater</a> for medical purposes even has a name: thalassotherapy. </p>
<p>In 1769, a popular British doctor <a href="https://en.wikipedia.org/wiki/Richard_Russell_(doctor)">Richard Russell</a> published a dissertation arguing for using seawater in “diseases of the glands”, in which he included scurvy, jaundice, leprosy and glandular consumption, which was the name for glandular fever at the time. He <a href="http://www.theatlantic.com/health/archive/2013/08/the-historic-healing-power-of-the-beach/279175/">advocated drinking seawater</a> as well as swimming in it.</p>
<p>To this day, <a href="http://www.nextavenue.org/top-9-places-healing-waters/">healing and spa resorts</a> by the seaside abound. They are thought of as places where people can not only let go of their troubles but, in some cases, <a href="https://www.spadreams.com/dead-sea-hotels/">even cure arthritis</a>.</p>
<p>But does the evidence actually stack up? Does seawater cure skin conditions and improve mental health symptoms? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149146/original/image-20161207-18036-5bwgdx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Doctors used to prescribe patients go to the seaside to improve health.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/search/sea-side?photo=WbBTlOk-CRY">Johnny Chau/Unsplash</a></span>
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<h2>Skin conditions and wounds</h2>
<p>Ocean water differs from river water in that it has <a href="https://web.stanford.edu/group/Urchin/mineral.html">significantly higher amounts</a> of minerals, including sodium, chloride, sulphate, magnesium and calcium. This is why it’s highly useful for skin conditions such as psoriasis.</p>
<p>Psoriasis is a chronic, autoimmune (where the immune system attacks healthy cells) skin condition. People with prosiasis suffer often debilitating skin rashes made of itchy, scaly plaques.</p>
<p>Bathing in natural mineral-rich water, including in mineral springs, is called balneotherapy and has long been used to treat psoriasis. There is also evidence for climatotherapy (where a patient is relocated to a specific location for treatment) in the Dead Sea being an <a href="http://www.jaad.org/article/S0190-9622(03)00916-2/abstract">effective remedy</a> for the condition.</p>
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<a href="https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=797&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=797&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=797&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1001&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1001&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149013/original/image-20161207-15197-nakoss.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1001&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">People with prosiasis suffer often debilitating rashes made up of itchy, scaly plaques on their skin.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
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<p>Patients suffering from psoriasis have themselves reported feeling better <a href="https://blog.23andme.com/23andme-research/what-patients-say-works-for-psoriasis/">after swimming in the ocean</a>, but this may also have to do with sun exposure, which has been found to <a href="http://www.tandfonline.com/doi/abs/10.3109/09546639609089534">improve psoriasis</a> symptoms.</p>
<p>Ocean swimming also has benefits for eczema, another immune-mediated condition. Swimming in the sea can be a good exercise option for those with severe eczema as they often struggle to exercise in the heat and chlorinated pools.</p>
<p>But the <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1468-3083.2012.04636.x/full">response of eczema sufferers</a> to saltwater is variable: some find it soothing, others uncomfortable.</p>
<p>There is some evidence to support the idea <a href="http://www.mgwater.com/transdermal.shtml">magnesium absorption</a> is <a href="http://www.progressivehealth.com/learn-how-to-treat-eczema-with-epsom-salt.htm">beneficial for the skin</a> of eczema sufferers – presumably because it makes it less dry – as those using Epsom salt baths will attest. This may happen because <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-4632.2005.02079.x/full">magnesium-rich seawater</a> may improve moisture retention in the skin, making it stronger and more rigid. </p>
<p>Because it is rich in other mineral salts such as sodium and iodine, ocean water can be <a href="http://www.abc.net.au/health/talkinghealth/factbuster/stories/2010/03/18/2849271.htm">considered an antiseptic</a>, meaning it may have wound-healing properties. On the other hand, swimming in the ocean with open wounds may expose you to potential bacterial infections.</p>
<h2>Hay fever and sinus issues</h2>
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<a href="https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149021/original/image-20161207-25727-fky0w6.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>
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<span class="caption">Many people with sinus conditions and hay fever find nasal irrigation with salt-containing solutions helpful.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
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<p>Nasal irrigation, or flushing of the nasal cavity, with salty solutions is used as a complementary therapy by <a href="https://www.ncbi.nlm.nih.gov/pubmed/14712112?dopt=Abstract">many people suffering from hay fever</a> as well as inflammation and infection of the sinuses.</p>
<p>Ocean swimming and exposure to the salt environment are possibly associated with reduced symptoms of hay fever and sinusitis, as well as other respiratory symptoms. </p>
<p>This is because the <a href="http://www.aafp.org/afp/2009/1115/p1117.html">saline effect on the lining of sinuses</a> may reduce inflammation, although scientific evidence for this is less robust.</p>
<p>The director of clinical services at the medical charity Allergy UK claims people who live by, and swim in, the sea tend to have <a href="http://www.dailymail.co.uk/health/article-2385191/Sea-swimming-add-years-life.html">healthier respiratory systems</a>. </p>
<p>She says because seawater is cleansing and mimics the body’s own fluids in the lining of the airways, it doesn’t irritate them.</p>
<h2>Meditation and relaxation</h2>
<p>Exercising in natural environments has been shown to have <a href="http://www.sciencedirect.com/science/article/pii/S0277953612003565">greater benefits for mental health</a> than exercising elsewhere. This is because it combines the benefits of exercise with the restorative effects of being in nature. Swimming in the ocean is no less the case.</p>
<p>It can be relaxing, meditative and reduce stress. In his 2014 book <a href="https://www.washingtonpost.com/national/health-science/blue-mind-explores-the-calming-effect-that-water-has-on-people/2014/07/28/471d7a5a-11bb-11e4-9285-4243a40ddc97_story.html?utm_term=.1309b168eeb9">Blue Mind</a>, marine biologist Wallace J. Nichols brought together evidence for why people find themselves in a meditative and relaxed state when they are in, on or under water. </p>
<p>One reason is the <a href="http://www.sciencedirect.com/science/article/pii/S0149763405802106">breathing patterns used during swimming</a> and diving. These stimulate the parasympathetic nervous system (the system that controls organ function and quietens the brain) and have effects on brain waves and hormones that influence the brain positively. </p>
<p>The weightlessness of water can also have a <a href="http://bmhmag.com/what-swimming-can-do-for-mental-health/">calming effect on the mind</a>, <a href="http://www.sciencedirect.com/science/article/pii/S105381190800757X">even changing</a> or slowing down brain waves. </p>
<p>It can help provide a distraction from life, giving a sense of mindfulness, which is a state in which one is aware of one’s surroundings in a meditative sort of fashion.</p>
<p>Hydrotherapy (water therapy) and swimming have also been <a href="http://psychcentral.com/blog/archives/2010/08/04/how-swimming-reduces-depression/">shown to decrease symptoms</a> of <a href="https://www.psychologytoday.com/blog/inner-source/201407/cold-splash-hydrotherapy-depression-and-anxiety">depression and anxiety</a>. <a href="https://www.ncbi.nlm.nih.gov/pubmed/20178872">One study showed</a> the effects of balneotherapy were comparable to a commonly used anti-depressant drug called paroxetine.</p>
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<a href="https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149022/original/image-20161207-13648-bdnm79.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Being in the sea can be a meditative experience.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/search/swimming?photo=g0n0FLM3UTg">Jonny Clow/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>Cold water therapy</h2>
<p>Hydrotherapy has been <a href="http://www.sciencedirect.com/science/article/pii/S1934148209005516">extensively used in rehabilitation</a>, but here I will focus on the health benefits of swimming in cooler ocean water. </p>
<p>Cold-water swimming <a href="http://journals.co-action.net/index.php/ijch/article/viewFile/17700/20171">activates temperature receptors</a> under the skin that release hormones such as endorphins, adrenalin and cortisol. These have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049052/">therapeutic benefits</a> for musculoskeletal conditions – <a href="https://theconversation.com/hidden-and-unexplained-feeling-the-pain-of-fibromyalgia-48319">such as fibromyalgia</a>, which is a condition with chronic pain and tenderness all over the body – and skin discomfort. </p>
<p>Recurrent cold water exposure may also lead to enhanced function of the parasympathetic nervous system, which helps with organ function. This has been linked to an increase in the <a href="https://www.ncbi.nlm.nih.gov/pubmed/12546194">release of dopamine</a> and serotonin.</p>
<p>Depending on the temperature, swimming in colder waters will <a href="https://www.ncbi.nlm.nih.gov/pubmed/7068314">use up more calories</a> to preserve body temperature – although the overall effect on fat mass is controversial.</p>
<p>Frequent <a href="http://link.springer.com/article/10.1007/BF00242274">exposure to cold water</a> has also been shown to <a href="http://www.circumpolarhealthjournal.net/index.php/ijch/article/download/17474/19822">increase the body’s immunity</a>.</p>
<p>Overall, you would be wise to make ocean swimming a health habit.</p><img src="https://counter.theconversation.com/content/68583/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sergio Diez Alvarez 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>Seawater has been used to treat skin problems, sinuses and mental health issues for centuries. And the evidence largely stacks up.Sergio Diez Alvarez, Director Of Medicine, The Maitland and Kurri Kurri Hospital, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.