How to Stay Hydrated in the Heat Ep 20

Exercising in the heat is not all about drinking a ton of water. While it is important, it's more important to manage your core temperature.

Welcome to the Find Your Edge podcast. Get ready to dive into all things training, nutrition, recovery, and more. Whether you're a new or experienced endurance athlete, a weekend warrior, or someone who just wants to improve your health and fitness, this podcast is for you. I'm Chris Newport, founder, head coach, ready Registered dietitian, exercise physiologist, and certified personal trainer with the Endurance Edge and the Fueling Edge. With more than 20 years experience in the fitness industry, 18 years in multi-sport, and over 10 years as a sports nutritionist, I'm speaking with athletes and experts about key actionable steps you can take to reach and sustain peak performance and health.

Let's do it. Hello and welcome back to the Find Your Edge podcast. I am your host, Chris Newport. And today we are talking all about how to hydrate in the heat. So if you are like us in North Carolina, it is hot and it can get humid and instantly hydration becomes an issue or overheating becomes an issue. So I wanted to make sure that everybody has some strategies in their pockets to go into the summer. Safely. So first of all, let's define dehydration. It is the excess fluid loss that impedes normal function. And this is just normal function in life, as well as in whatever activity that you're trying to accomplish. So as little as 2% loss, 2% body weight loss can reduce your performance and delay what's called gastric emptying. So that's basically how quickly can your stomach empty into your small intestines. And that's where we're able to really deliver all of those appropriate nutrients to the working muscles. It is still one of the most common issues with athletes in particular for runners and triathletes, because there is generally minimal stopping. You're just continually going and going. And in that heat, this can definitely be an issue. So let's also define sweat. What is it? So it is your body's method of evaporative cooling. So exercise generates heat and we store heat as humans. So we have this metabolic heat production, and that can also be affected by some of our environmental conditions like evaporation and radiation and convection and all these other things like heat from the sun, heat from the surface that you might be on, or like a playing field, that kind of thing. One way or the other, as the core temperature rises, your body responds by sweating. So something to keep in mind, hydration is not about putting more fluid into your body to be able to manage it. It's all about managing core temperature. And that's not just about hydration. That's also about keeping your core temperature down with appropriate cooling methods. So we're going to go over all that, but sweat contains mostly water, but it also contains sodium. It has chloride, it has potassium, it has magnesium, calcium, urea, and several other things. And your average sweat losses can be very, very minimal. So hardly any, I've seen in the literature up to 3 liters per hour. I've not personally seen that. There was one study actually done at Ironman World Championships in Kona, and the reported average loss in the research study that they did out there was a little over a liter an hour. So about 34, 35 ounces. We do sweat testing in our office as well, both home sweat testing kits that you can do wherever you are in the country or even in the world. And we also do sweat testing in our exercise physiology lab. So we've collected data from. Those people and females on average sweat about 22 ounces per hour and about 71 milligrams of sodium per ounce is in that sweat. And males sweat about 36 ounces. So a little bit over a liter, similar to what those reports that we saw in Kona and about 70 milligrams of sodium per ounce. So kind of interesting that males and females have some pretty similar electrolyte concentrations, but generally speaking, females tend to sweat a little bit less. Males tend to sweat a little bit more from what we've seen in our lab. And then again, from electrolyte ratios or electrolyte differences we've seen with our sweat testing. And this is not something that you can necessarily do on your own, but we've seen as little as 215 milligrams of sodium lost in an hour to well over 5,000 milligrams of sodium per hour. So just for reference, 2,400 milligrams of sodium is what is in 1 teaspoon of salt, just good old-fashioned table salt. So another thing to keep in mind is that sweat rate varies. So first and foremost, it depends on your body size. So generally the bigger you are, The more you're going to sweat. Your fitness or training status also makes a difference. So the more fit you are, actually, the quicker you respond to that rise in core temperature and the faster you start sweating. So that's actually a good thing. Your exercise intensity is another piece that is critical to that puzzle. The slower you're going, the less heat you're generating, and the faster you're going, the more heat you're generating. Thereby you're going to sweat more as a response to that core temperature rise. The environment of course is huge. Temperature and humidity play into that, into how much you sweat. Your metabolic rate, that's sort of at rest, will make a difference as well. If you have a higher metabolism, you're going to sweat a little bit more and whether you're acclimated or not to whatever environment you're in. So it's just starting to get hot here in North Carolina. But as the summer progresses, gradually we start to acclimatize. Doesn't mean we necessarily like it, but our sweat rate sort of normalizes throughout the summer. It's going to be, we're going to lose more electrolytes in the early part of those, that acclimatization period. Clothing is also something that affects your sweat rate. The type of fabric you're wearing, whether you have layers on, what type of colors you're wearing. In fact, So for example, cotton absorbs a lot of fluid or a lot of sweat, but it also doesn't release that sweat very easily. So it just stays wet. So that's, that's not a great thing that we want to be wearing. Technical fabrics, on the other hand, sort of wick away that moisture. Of course, it doesn't matter if it's humid, the moisture in the air is just too thick. Or the higher the humidity is, the moisture has a hard time, whether you're on technical fabrics or not, to be able to release. And then of course, if you're wearing layers, the more layers you're wearing, the more you're going to sweat. And if you're wearing darker colors, you're going to sweat more as well. So here's one of the things we want to start to address is how do you tell if you're hydrated? There's a couple of different methods and The majority of them are pretty darn easy. So first and foremost is your urine color. So we've got a free chart on our website. So check it out at theenduranceedge.com. It's got a nice little color chart. There are 8 levels in terms of like the colors of yellow, but we want to focus on being what we call under 3. So 1, 2, and 3 are the lightest colors or lightest shades of yellow. We want to make sure that that's where most people are. Um, generally speaking, to make sure you're appropriately hydrated, the darker the urine, the less you're hydrated. And that's when you want to either hydrate more before you're going out to exercise, or just make sure that you're managing that appropriately. Keep in mind, in particular, B vitamin supplements will make your urine very electric yellow, but we still want to make sure that it's very light colored yellow. So that's a super easy way for you to tell whether you're hydrated or not. Thirst is another easy way. Are you thirsty? And then like in the morning, how much of, how much weight have you lost? So just making sure that you're staying hydrated in that way. So speaking of weigh-ins, one of my favorite ways to tell whether you're hydrated in particular surrounding exercise is to do pre and post weigh-ins. So grab yourself a super cheap scale. Doesn't have to be anything particularly fancy. Throw it in the back of your car if you have to travel somewhere. And just get in the habit, especially if you're somebody who sweats very heavily, of weighing yourself before your workout and after your workout, and just try to be relatively consistent in terms of what you're weighing yourself in. So if you weigh in your shoes beforehand, be sure to weigh in your shoes afterwards. Keep in mind that 1 pound lost is the equivalent to about 16 ounces. So in other words, a pint's a pound the world around, right? So we want to make sure that we're putting that back in. You may have lost a whole lot. And obviously I've had people who have lost 6, 7, 8, 9 pounds. Obviously you can't drink that much all at once. So that's going to have to be something that you'll have to gradually put back in. Another thing that's relatively easy to use, it's just a little bit more technical, is something we called urine specific gravity. And there's a device called a refractometer, and I'll be sure to put some links so that you know what to actually purchase, but you can get a refractometer. They're pretty cheap these days, as well as some disposable pipettes and some disposable cups. Actually pee in a cup and then take a little drop of that urine, kind of put it on the, almost like a slide back in your high school chemistry days. And then you look through a little, a little hole to see what your urine specific gravity is. And you want it to be in a particular range. That's specifically more important for somebody who sweats. A very, very large amount and you know who you are and it is okay. And there's nothing wrong with you. So now that we know how to test that hydration or what we're looking for, here are 6 strategies to being sure that you avoid dehydration. First and foremost, if you can acclimatize, do it. So the minimum timeframe is about 2 weeks. So if you're traveling somewhere, try to be there at least 2 weeks ahead of time. I know that's oftentimes not, uh, particularly possible, but try to acclimatize if you can, because again, you're going to lose more electrolytes in your sweat on the front end of acclimatizing. Once you get used to it, things will normalize. Our second tip, try to exercise at the coolest time of the day. So generally speaking, These are mornings or evenings because of course the sun, which is going to make you hotter, raise your core temperature because of its radiation. Generally mornings or evenings are going to be the best times to work out. And hopefully you'll have some level of control over that. I also kind of put a little caveat here is don't be silly. I've done this before. I've tried to say, oh yeah, I'm going to acclimatize really quickly and go out to a blacktop track. And do a track workout at 1 o'clock on a super hot day to try to acclimatize quickly. Well, that was an entirely poor choice. Also keep in mind, what is the goal of your workout? If you're really trying to increase your speed and it's super hot out, you may be gaining fitness, but are you going to get the best quality workout? So I know I'm not one who's a particular fan of treadmills, but some Sometimes it just ends up being the smarter choice, not only for you physically and avoiding dehydration, but also to get the most out of your workout. So in other words, to gain as much fitness out of your training time, right? Our third tip, know your hydration losses and your needs. So again, this goes back to my little tip about weighing yourself before and after workouts. I'll oftentimes have athletes log pre-weight, post-weight, as well as the time of the day that they went on a workout. What was the heat and what was the humidity for that day or for that time that they went out for that workout? So then we can start to see some general trends and be more prepared. Also knowing your urine. Again, know where you are before you go out there, be prepared. and then get sweat tested. Sure. Is this a shameless plug for us? Absolutely. But we provide a really useful service for people to be able to know what their electrolyte replacement needs are. There are other companies out there certainly who do this type of testing. Just be sure if you do use them that you're actually sweating during an actual workout. It can't be something that you, that you do seated, uh, that particular test is not effective for Um, extrapolating what you lose during exercise. Fourth tip is wear sunscreen. Burns do not allow your body to cool. So if your skin is burning, your sweat or your blood flow is going towards the skin and trying to release that heat and it can't do it. So be sure that you're wearing sunscreen or reapplying frequently, even if you have darker color skin. Similarly, our fifth tip, tip number 5, is wearing light colors and breathable fabrics. So light colors, light gray or white or yellow or pink, those types of colors, and avoiding the dark colors like black and navy blue and those types of things. Like, I know sometimes there's not a lot of control over what type of team jersey you wear. But if you can purchase a, you know, a shirt or kits or uniforms or whatever it is that are going to be lighter colored, that is definitely an advantage so that you're not quite so hot. And then of course, like I said, breathable fabrics are super important as well. And our 6th tip is to plan your pre, during, and post-workout cooling strategies. So this is super huge and let's get into that. A little bit more because cooling strategies truly are key. You cannot drink enough water to be able to cool your body down. In fact, you can actually harm yourself when you're over-drinking during, in the heat. Cooling strategies and managing core temperature are the most important thing when it comes to this. So what should we do pre-workout? Get in the air conditioning. That's one tip. I had one athlete who, before a race, he sat in his car with his air conditioning blasting, and he also had what's called a cooling vest on. So this literally looks like a vest, and then there's little slots in it where you can put ice packs. I've also seen some that are circulating water or circulating cold water. So that could be an option as well. Again, just a reminder to do those pre and post workout weigh-ins. It's not necessarily a cooling strategy, but at least it keeps you in the know as to how much total fluid you've lost. And this is one of my favorite ones. Icy cold drinks immediately before you start. So in the literature, we've seen something called ice slurries. Kind of reminds me of those drinks that you get at like, uh, gas station or whatever, but drinking your water, it can even be a little bit of sports drink immediately beforehand, somewhere around 5 to 15 minutes beforehand, something very, very like, like slushy type of consistency, really cold, because that actual lowering of the temperature of your GI tract actually affects the core temperature. And then during your workout cooling strategies. Still are important. Just like I said, with the ice slurry beforehand, drink those icy drinks during your workout as well. So a little tip, if you're, uh, especially if you're a cyclist or somebody who's on like a team sport, you can take your water bottles and fill them either a third of the way or halfway and kind of tilt them onto the side. I wouldn't necessarily suggest putting them all the way on the side because you don't want to, um, block your ability to actually open the bottle or get something out of a straw, but you can kind of tilt them on their side. And it kind of frees an ice cube inside of it. You can also do things like eating ice. You can even put ice in your hat or in your clothes. Another one that I've seen in the literature is actually holding ice or holding ice packs. And one of our favorite tips is that you take ice and put it in a piece of pantyhose, and then you tie a knot on it and you can take that pantyhose and put it in your sports bra. You can put it in a jersey. You can put it in your shorts. Uh, you can put it in a hat. And then as that ice melts, now all you have left over is this little, little tiny piece of pantyhose that's either easy to throw away or doesn't take up really any weight or any space in your hat or in your clothes or whatever. Another thing I would suggest for cooling strategies in the heat are something called cooling towels. They literally look like kind of like a chamois sort of towel. And I've seen people who have little like lunchbox coolers with ice and water in them, and they'll keep those cooling towels immersed in them and then wear them until they can't be cool anymore and then wring them out and then return them or swap them out for the other towel if that is at all possible. So Same thing. I'll link to some of these different types of products either on our blog or in descriptions. Another tip that I have in terms of staying cool during your workout is planning your route carefully. So making sure that you've got shade, making sure that you're going in at the appropriate time of the day, or you're not going to be exposed to excess vehicle exhaust, which of course is, can be hot. Now, of course, if you're in a race or if you're in a game or someplace where you don't necessarily have control over that, And then make sure to take care of those other items like the cooling towels, the ice, and the hats, frequent breaks, and then carry that hydration with you if you can, especially for runners and cyclists. So have either a race belt on or, or not necessarily race belt, but a hydration belt or hydration pack or some sort of handheld hydration. And then of course, be cautious. Little tip here, be cautious with drinking too much water. This is actually more serious than dehydration. The dilution of your electrolytes in your bloodstream can lead to a serious condition called hyponatremia. And there are actually different types of hyponatremia, but one way or the other, it's the excess dilution with too much water so that it is possible. You can drink too much. So when you're doing those pre and post weigh-ins, if that's something that you'd like to do, Be sure you're not gaining weight. That's really important. And generally speaking, this happens to slower marathoners who tend to be women, and they're just kind of stopping along the way and they're drinking water. So be sure that you do have some sort of electrolyte beverage instead of just water. Post-workout cooling strategies. Some tips there are making sure that when you are finished with your workout, Or your race or your game or whatever it might be, try to get into a cool location. And by be indoors, it might be just in a shady spot or under a tree. If you're really overheated, or if you're starting to see those stars, definitely lie down and try to elevate your feet above your heart. If possible, you can even put ice packs over the chest, in your armpits, and even in your groin to really cool down those spots that tend to get more heated. Uh, again, you can try a cooling vest if you have access to doing like a, a post-workout ice bath or some type of cold water immersion, or, you know, going through a water hose or something like that. Um, that will help you again, manage core temperature. Cause it's not all about hydration. It's about managing core temperature. You can do those icy drinks again. You can have some cold icy sports drink beverage. And then if you can, or if it's an appropriate time or place, you can remove some excess clothing just to cool yourself off. And then again, if you are doing your pre and post weighs, make sure you're doing that as well. All right. So let's put all these pieces together. Again, it's all about cooling both internally and externally. So putting icy cold drinks inside your body, as well as icy and cold things outside your body to be able to manage core temperature. Exercising in the heat is not all about drinking a ton of water. While it is important, it's more important to manage your core temperature. Be sure to know yourself so that you can best manage your fluid and electrolyte losses. So again, keep little logs of your pre and post weigh-ins. Be mindful of the conditions that you're going out in, try to watch the weather and try to be mindful of the time of the day that you're going out. So as best as you can control what you can so that you're avoiding dehydration or hyponatremia or any sort of heat-related illness and try to plan as best as you possibly can. So having said all that, we are here for your sweat testing need and your metabolic needs and, um, nutrition counseling, fueling, and hydration solutions, those kinds of things. Our home sweat test kit, if you're not in North Carolina or in our area, can be found at theenduranceedge.com. Comes with a 15-minute complimentary consult with me, your hydration expert. You can also check out our free hydration guide on our website, same place, theenduranceedge.com, and download that urine color chart that I was referring to. This is a great thing that you can print out, especially if you have kids, because kids do not release heat as well as adults do. So you can kind of cut that out and put that like on the back of a bathroom door. And then of course, if you are listening to this and you enjoy the content, please make sure you subscribe, check us out on social media, on Instagram and Facebook at theenduranceedge.com and The Endurance Edge. And thank you so much for listening. I hope this helps you in your journey to exercising in the heat and humidity. And good luck out there, folks.