\n<\/p>\n
H<\/span>ydration is important. In temperatures like those we\u2019re increasingly seeing in much of the world, sweating can be the only way for our bodies to cool down, and our thirst isn\u2019t always the best indicator of how much water we\u2019ve lost or need. The consequences of not<\/em> being sufficiently hydrated as temperatures creep towards the 40s can be severe, and can kick in much faster than most people realise. The good news is that remembering to drink plenty of water at regular intervals throughout the day will be enough for most people to avoid the worst. But if you\u2019d like to understand why dehydration is so dangerous, whether you really need extra electrolytes, or if a cup of tea really can cool you down, read on.<\/p>\n To start with, it\u2019s helpful to understand that our bodies are producing heat \u2013 and therefore losing water \u2013 all the time. \u201cAll the cells in our body are constantly using fuel for energy for various different processes, whether that\u2019s movement or just staying alive,\u201d says Dr Lewis James, a lecturer in sport, exercise and health sciences at Loughborough University. \u201cAbout 75 to 80% of the energy that we use appears as heat.\u201d If we didn\u2019t have any way of dissipating this heat, then even lying on the couch would see your body temperature rise about 1.3C in a single hour (already enough to make you noticeably feverish) \u2013 but of course, we do. Normally, we lose a decent amount of heat through a combination of convection and radiation: the blood vessels in our skin dilate, allowing the blood to be cooled by the outside air. The problem is that when the external temperature goes up, this process becomes less effective and eventually stops working altogether. At this point, our main way of losing heat is through sweating: our bodies produce tiny droplets of warm water mixed with trace minerals, which (usually) evaporate on contact with the air, drawing heat away from the skin in the process. And as we rely more on sweating, it\u2019s increasingly important to replace the fluids our bodies are losing.<\/p>\n <\/span>Experts advise drinking a couple of glasses of water first thing. <\/span> Photograph: Posed by model; skynesher\/Getty Images<\/p>\n \u201cDuring a normal day, a normal individual who doesn\u2019t exercise loses very little water through sweat, probably less than 500ml a day,\u201d says James. \u201cBut if the outside air temperature is hotter than our skin, sweating is one of the only ways that we can lose that heat. Typically, it doesn\u2019t get that hot in the UK, but certainly when it\u2019s above, say, 35, 36C, that\u2019s where it becomes a concern.\u201d<\/p>\n Over the short term, even mild dehydration can impair how your body and brain function. \u201cTypical symptoms include headaches, fatigue, reduced concentration and poorer physical performance,\u201d says Bridget Benelam, a nutrition scientist at the British Nutrition Foundation.<\/p>\n \u201cThe body responds [to dehydration] by conserving water: processes like temperature regulation and circulation become less efficient. Over longer periods or at more severe levels, dehydration puts real strain on the body.\u201d This can, she says, lead to impaired cognitive and physical performance, \u201cincrease the risk of issues like constipation, urinary infections and falls, and in extreme cases be life-threatening\u201d. At the most severe end, dehydration is fatal, but the problems start to compound before that: you\u2019ll be thinking too slowly to look after yourself.<\/p>\n So how can you tell when you\u2019re dehydrated? Don\u2019t wait until you feel thirsty, as this tends to happen after you\u2019ve already lost 1 to 2% of your body mass in fluid, meaning that you\u2019re already suffering from mild dehydration. The simplest \u2013 and, for most people, best \u2013 way remains the pee test, says James. Subtle changes in colour can alert you before thirst kicks in. \u201cIf you\u2019re producing very small amounts of urine and it\u2019s very dark in colour \u2013 from dark yellow to brown \u2013 then that can indicate dehydration,\u201d he says. \u201cIt\u2019s not, as you might read in some places, an absolute indication \u2013 your kidneys are marvellous at concentrating water when your body thinks it\u2019s needed, so you\u2019ll sometimes have concentrated urine even when you\u2019re not really dehydrated \u2013 but it\u2019s a fairly reliable signal. And the opposite is also true: if you\u2019re producing pale-coloured urine, you\u2019re probably well hydrated.\u201d<\/p>\n <\/span>A hot cup of tea can help cool the body down.<\/span> Photograph: Halfpoint Images\/Getty Images<\/p>\n Realistically, of course, you want to stay ahead of this, which is why it\u2019s sensible to make a conscious effort to drink more water at regular intervals. \u201cPeople often wake up already dehydrated because our bodies lose significant water overnight through respiration and sweating in warm bedrooms,\u201d says the University of Brighton\u2019s Dr Neil Maxwell, a specialist in applied environmental physiology. \u201cI would imagine 70-80% of the population will start the day on the back foot by being dehydrated after a hot night during a heatwave. Starting the morning with 300-500ml of water sets a stable baseline before daytime heat spikes.\u201d<\/p>\n Just in case you\u2019re considering it, though, there\u2019s no real upside to glugging down a day\u2019s worth of water first thing in the morning: you\u2019ll just excrete anything that can\u2019t be immediately used by your tissues or processed by your kidneys. In general, it\u2019s better to drink moderate amounts reasonably frequently. \u201cIf you have three meals a day, then try to drink a large glass of water with your meals,\u201d says James. \u201cIf you\u2019re drinking a pint of water with every meal, and then you have the odd drink in between meals, you will most likely have an adequate amount of water every day. Drinking with meals also slows down the rate at which the water passes through your system, and might help you to absorb it better.\u201d If you\u2019re exercising, you\u2019ll want to step this up a bit: the standard advice is to aim for about 500 to 750ml of water for every hour of intense training, depending on how heavily you sweat. But it also helps to stay ahead of the game: if you\u2019re heading to the gym or out on the road, drink about 500ml of water a couple of hours beforehand, giving your kidneys time to process the fluid, balance your blood volume, and excrete anything it can\u2019t handle, so you\u2019re not sloshing around unnecessarily.<\/p>\n <\/span>A pint can be refreshing\u2026 but best stick to one.<\/span> Photograph: coldsnowstorm\/Getty Images\/iStockphoto<\/p>\n Does it matter what you\u2019re drinking? As long as you\u2019re keeping it non-alcoholic (and relatively low-calorie), only in the sense that some drinks might muddy your body\u2019s signals. \u201cSparkling water and diet soft drinks can provide effective hydration, but the carbonation can cause a feeling of fullness or bloating that may prematurely signal the brain satiety centres, causing a person to stop drinking before they are fully rehydrated,\u201d says Maxwell. \u201cRegular consumption of highly acidic diet soft drinks or flavoured waters containing citric acid can contribute to dental erosion, a factor to balance against their hydration benefits \u2013 though not a reason to avoid them entirely. Tap water or filtered water remains the gold standard for daily hydration during a heatwave, but the best drink is ultimately the one you will actually consume.\u201d<\/p>\n Fruit juice and milk (or plant-based milk alternatives) are fine for hydration, but come with the caveat that it\u2019s easy to overconsume calories if they\u2019re your go-to option. \u201cMilk is hydrating, provides some nutrients, including protein, calcium and vitamins,\u201d says Benelam. \u201cFruit juice and smoothies hydrate and contain vitamins but also free sugars. The recommended limit is 150ml per day \u2013 one small glass.\u201d If you\u2019re making your own homemade smoothies, of course, you can always cut down on sugar by going heavier on the veg than the fruit: celery, spinach and cucumber all help with hydration while also adding important minerals.<\/p>\n When it comes to tea and coffee, you might have heard that caffeine acts as a diuretic, which causes you to produce and excrete more urine. This isn\u2019t really true in any way that most people need worry about: the effect is so minuscule that you\u2019d need to down around five espresso shots at once to notice a real diuretic effect. \u201cAny diuretic effect you get is massively outweighed by the positive water intake you get from the drink, especially if you\u2019re the sort of person who doesn\u2019t drink much water otherwise,\u201d says James. Caffeine might mask the symptoms of thirst slightly, and so \u2013 once again \u2013 you can\u2019t rely on the fact that you feel satisfied after you drink it. Otherwise, it\u2019s fine.<\/p>\n Booze is a bit trickier. Technically, one low-ABV drink of about 4% can have a net-hydrating effect: though alcohol is a much more potent diuretic than caffeine, a pint of lager or a fruit cocktail can<\/em> contain enough water to offset the effect. This effect doesn\u2019t last, though: as you move to drink two or three, the higher alcohol concentration in your blood starts to suppress the body\u2019s anti-diuretic hormone vasopressin, leading to what some people call \u201cbreaking the seal\u201d. One pint might be lovely and refreshing, but leave it there.<\/p>\n <\/span>Vegetable juices deliver a hydration hit with added minerals. <\/span> Photograph: Kseniya Ovchinnikova\/Getty Images<\/p>\n You might imagine that glugging hot mugs of tea when it\u2019s over 30C is counterproductive, but the truth is a bit more nuanced. \u201cThe first thing to say is that personal preference matters,\u201d says James. \u201cMost people, if they\u2019re not drinking tea, like drinks that are cooler than room temperature more \u2013 so in that sense, you\u2019re likely to drink more [cold drinks] and so better defend against dehydration. But when we\u2019re talking about body temperature, there\u2019s some truth to the idea that tea can actually cool you down in certain situations.\u201d<\/p>\n If you have a cup of tea when it\u2019s already fairly warm outside, your body\u2019s heat receptors detect a rise in internal temperature and send signals to your brain to cool off. As a result, blood vessels near the surface of the skin widen, and your sweat rate goes up \u2013 a cooling response that\u2019s usually disproportionate to the amount of heat you\u2019ve taken on board. In contrast, if you have a cold<\/em> drink, the opposite happens \u2013 the cold fluid in your stomach pulls blood away from the skin, which means the drink is not cooling you down as much as you think. \u201cThe warming effect of a warm drink is cancelled out by the increased heat loss, while the cooling effect of a cold drink is cancelled out by the reduced heat loss, except for in very specific scenarios that tend to depend on environment,\u201d says James. \u201cIf you\u2019re in very humid conditions or you\u2019re exercising, you\u2019re not able to lose much heat to the environment because the sweat you produce can\u2019t evaporate fast enough.\u201d A good rule of thumb, then, is that if the sweat is already dripping off you, it\u2019s probably too hot to be relying on tea for hydration.<\/p>\n <\/span>Milk is hydrating and contains essential nutrients.<\/span> Photograph: Posed by model; Goran13\/Getty Images<\/p>\n What about electrolytes? There\u2019s been a huge marketing push for these in recent years, with supplement and sports drink companies galore suggesting that topping up your levels of potassium, magnesium and (especially) sodium is a necessary part of hydration for all \u2013 not just the athletic or very sweaty. But the evidence for that is, at best, mixed \u2013 especially since the majority of people in the UK already take in too much salt. \u201cFor the majority of people, you\u2019ll get enough electrolytes from food,\u201d says Brunel University\u2019s Prof Jos\u00e9 Gonz\u00e1lez-Alonso. \u201cIf you\u2019re having a banana or an apple during the day, you\u2019re already getting electrolytes \u2013 there\u2019s nothing magical about sports drinks.\u201d If you\u2019re exercising intensely or for a decent amount of time (more than 60 minutes, in hot weather), sweating much more than normal, or simply unable to snack regularly, then it can be helpful to top your levels up. If you\u2019re drinking a lot of water, it helps to stop your kidneys from immediately flushing it out. It also helps to balance the risk of hyponatremia, or diluting your blood sodium levels to dangerously low levels (the clue\u2019s in the name: hypo means low, natrium is the Latin word for sodium, and emia means in the blood). \u201cEven recreational exercisers and avid gardeners are at risk of hyponatremia if they aggressively overdrink plain water out of a fear of dehydration,\u201d says Maxwell. \u201cWhen you lose salt through sweat and flood your system with massive amounts of water, you dilute your blood\u2019s sodium levels, which can cause cells to swell and become dangerous.\u201d<\/p>\n This sounds scary, but it\u2019s only likely to occur if you\u2019re drinking large volumes of water very quickly, with no added salt in between. It bears repeating that, if you\u2019re not very physically active and eating and drinking normally, you should be fine. If you\u2019re doing something more strenuous \u2013 enough to make you sweat a lot \u2013 add a couple of salty snacks and consider supplementing with electrolytes. Other good dietary sources include avocados, sweet potatoes and spinach, while plenty of foods have a decent enough water content to top up your levels: cucumber, watermelon, strawberries and mango are all more than 80% water by weight.<\/p>\n So while drinks manufacturers make hydration sound highly technical, best practice is reasonably simple: drink a big glass of water every couple of hours, preferably with food, and add in more if it\u2019s hot, you\u2019re physically active, or planning to be so. \u201cThe nice thing with water is that if you have a little bit too much, that\u2019s not a bad thing,\u201d says James. \u201cIf you\u2019re thinking about energy intake, for example, just having a bit too much carbohydrate on a regular basis can lead to problems down the road, like fat gain or insulin resistance. Whereas if you drink a bit too much water, all you\u2019ll do is pee it back out. And so it\u2019s fairly easy to make sure you\u2019re drinking an amount of water that will mean that you are generally defended from dehydration from most scenarios in your life, with no downside.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":" Hydration is important. In temperatures like those we\u2019re increasingly seeing in much of the world, sweating can be the only way for our bodies to cool down, and our thirst isn\u2019t always the best indicator of how much water we\u2019ve lost or need. The consequences of not being sufficiently hydrated as temperatures creep towards the<\/p>\n","protected":false},"author":1,"featured_media":50728,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[51],"tags":[1647,108,4470,24864,37,813,24865,629,1931,5020],"class_list":{"0":"post-50727","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-health","8":"tag-beer","9":"tag-cool","10":"tag-drink","11":"tag-electrolytes","12":"tag-health","13":"tag-heatwave","14":"tag-hydrated","15":"tag-safe","16":"tag-stay","17":"tag-tea"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/50727","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=50727"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/50727\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/50728"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=50727"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=50727"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=50727"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}