Short Wave - How To Beat The Heat, Olympian-Style

Episode Date: August 14, 2024

Over the next week, forecasts project extreme heat across much of the South, Midwest and parts of the West. So, this episode, health correspondent Pien Huang helps us take heat training cues from Olympians, many of whom spent weeks preparing for a sweltering Paris Olympics, by training in the heat to get their bodies used to hot, humid weather. But heat training is not just for competitive athletes. It's recommended for people in the military and those who work outdoors in hot weather — and it could even be useful for generally healthy members of the public. Plus, we get into some important caveats about who is best positioned to heat train — and why doing so doesn't minimize the problems of a warming climate.Check out more of Pien's reporting on heat training.And, if you liked this episode, consider checking out our episodes on the dew point, the power of sweat and coping with extreme heat.Questions or ideas you want us to consider for a future episode? Email us at [e-mail]. We'd love to hear from you!See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, shortwavers, Rachel Carlson here. Usually I am a shortwave producer, but today I'm a host. And I don't know if it's just me paying, but this summer has felt so, so sweaty. Not just you, so sweaty. Okay, good, because I'm feeling kind of self-conscious about it, but I also know it's not just me. Meteorologists say the summer is on track to be one of the hottest on-rector. And thanks to climate change, heat waves are more frequent and intense.

But what if I told you that if you are a generally healthy person, you can actually train your body to better manage the heat. Ping, this is exactly the kind of health reporting I want to hear. Thanks for bringing your expertise as a health correspondent on the science desk. You know, Rachel, I draw from the best, like our dear recently departed Olympics, the International Olympic Committee actually recommended that athletes heat train and preferring. for the Paris Summer Olympics, so, you know, this is tried and tested by the greatest of all time. I love the sound of this already. Okay, but big caveat.

A lot of us are not Olympic athletes, unfortunately, so maybe we cannot pommelow a horse or casually run a marathon. And it also stands that the heat training regimens for professional athletes may need to be very watered down for the rest of us. But to give you the gist, it's called a climatization when you do it outside or acclamation if you do it inside, if you do it inside, and it involves controlled exposure to heat and humidity over time, which basically increases your body's resilience to hot, humid conditions. And this happens naturally for a lot of people. People acclimate to heat in the location where they live, work, and play.

So this means that people who live in warmer regions will be able to withstand higher temperatures during their regular work and school days than people who live in cooler regions. This is Eugene LeVar. He's the chief heat officer in Arizona. And he's in charge of figuring out their extreme heat preparedness plan. And he also knows from the spork that a lot of heat deaths in Arizona happen because people forget the things they're supposed to do. He says living somewhere, being used to the heat doesn't actually mean you're not susceptible to it. Yeah, I hear that. And I feel like that's me in Los Angeles, which I know isn't even the hottest place at all in the U.S.

Right. I mean, last year, Phoenix, Arizona hit 110 degrees, 31 days in a row. 31 days, wow. Yeah. But even if you don't live in a state that hot, Eugene says that there are multiple health studies that indicate that there are benefits to training your body to manage heat. We see increased sweating efficiency. You see the ability to perform work with lower core temperature and heart rate, increased skin blood flow at a given core temperature. This kind of sounds like magic. I'm not going to lie. I know, but it's not magic because it's science. It's science. Okay. So today on the show, the science of tackling the heat, we're going to get into the details of how to improve your body's tolerance to this very hot summer.

And we'll also get into some very important caveats. You know, it's not for everyone and it's not going to solve the problem of climate change. I'm Rachel Carlson. I'm Ping Huang. You're listening to Shortwave, the science podcast from NPR. Okay, ping, heat training. How does this work? I'm kind of imagining like a five-step program and you get a little heat certificate at the end that says like you're acclimatized. Not quite. Not yet, at least for people like you and me, although the Olympic organizers did publish a guide for athletes that recommended heat training ahead of events. And throughout the guide, they recommend things like how much to train and where to train. So like somewhere warm? Uh-huh, yep. And among other things too. Like, I. how to hydrate and take cooling breaks.

And it speaks to the broader point about the manuals on heat training even outside of the Olympics. They all focus on athletes, outdoor workers, and people in the military. The templates in the sports science literature, which I question whether it's applicable to the public, it's actually continuous exposure every day between one and two hours. Oh, wow. Jason Lee is head of the Heat Resilience and Performance Center

at the National University of Singapore, which is, of course, also a famously hot and humid place. And he says that one or two hours is probably too much for the general public, which brings me, Rachel, to two very important caveats. One is that heat training is not for everyone. Heat-related illness is serious. It can be deadly and it can come on quickly. Right. Things like heat stroke, you mean?

Exactly, yeah. So heat stroke is a very serious condition where a person's core temperature is generally a 104 degrees or higher and they are in an altered mental state. So it can lead to organ failure, it can lead to death, and it can even happen if you're not doing competitive sports, but you've just stayed out in the heat too long without properly hydrating. So if there are any listeners that pursue some heat training in their personal lives, it's very, very important for them to listen to their bodies at every step along the way. You know, if they're having questions or doubts, they should be checking with their doctors before they start.

And please, please, please, they should be trusting their guts. So if it's feeling like the heat training is getting too intense, stop, find a place to cool off and hydrate. So important, we got to trust our bodies. So what's the other caveat? Right. So number two comes from climate scientists. And they reminded us that it should not be left up to individual people to adapt to this warming planet and then just say, it's fine. You know, instead, the ultimate global strategy is still. for governments and corporations to cut the pollution, which largely comes from burning fossil fuels,

and that is responsible for this global warming. Okay, another super important caveat, thanks, Ping. And in the meantime, on the way to hopefully curbing pollution, how does Jason recommend someone, like me, you know, regular, completely non-Olympic athlete? How does he recommend I might try to acclimatize? Yeah, so for everyday people, Jason's advice is to take it slow, and take it easy. So definitely give your body time to adapt and adjust and take long rest breaks in between.

He says it's best to start heat training before or just as the weather starts getting hot. Based on the sciences, right, I would say that exercise every other day progressively in a hot environment. So assuming Monday comes, go out for a 50 minutes walk, rest on Tuesday, go for a 30 minutes walk. On a Wednesday, rest on Thursday, you get the idea. Basically, get yourself adjusted to this new hot environment so that the physiological responses will take place over time. Okay, this feels more doable, like 15-minute walks or runs, 30-minute walk or run. That seems more realistic, I think. Yeah, and the caveat here, too, is with rest in between.

You also have to keep doing it. Research shows that it takes a few weeks of gradually increasing your heat exposure to get used to the heat, but maybe just a week or so out of the heat to lose it. Oh, no, a week. Okay. So how do I know if my body's heat acclimatized? Like, I feel like I'm just picturing one day I'm going for a run and suddenly I have, you know, the heat tolerance of an Olympian. Okay.

Okay. It might not be like that. Okay. That was, yeah, that was ambitious. It's because heat training is not like a one-size-fits-all regimen. So Jason told me that everyone's individual heat tolerance depends on their age, their baseline aerobic fitness, how healthy their immune system is. But a good indicator that you're acclimatized is that you're going to be more sweaty. Nice. So heat acclimatization, as I say, is the process usually two to three weeks, right?

So what it does at the end of that two to three weeks, basically it elicit positive physiological adaptations. And the very clear one is that it's an increase in your ability to sweat. That's two to three weeks for a trained athlete, and it might be a little bit longer for you and me, Rachel. But the sweat has the same purpose for all of us. As it evaporates, it cools the body down. And cool fact here, your sweat will also become more dilute. So as your body gets better at using water evaporation to cool down, it also gets better at conserving the sodium, the electrolytes that you need to keep your body going. Also, your circulation will improve and your blood volume will increase.

so your heart won't have to work as hard to pump blood throughout your body. But this is all assuming that you've drunk enough water to produce all that sweat and also that it's not so humid out that your sweat can't evaporate. Got it. Okay, so it's light exercise, staying hydrated, listening to your body. Uh-huh. And ideally, all of this is done leading up to the hottest time of year generally. But even now, it can still be worth trying if you've been huddled up in air conditioning all summer,

especially if there are things you want to be doing outside. If you want to be skateboarding, running, picnicking outside, and you're in a place that's going to be hot for a bit longer, like the southern and southwestern U.S., mid-Atlantic where I am in D.C. This is so great ping. I mean, I feel inspired, but there does have to be a limit as to how much heat is too much heat, right? Yeah, for sure.

And the thing is that there's no concrete outdoor temperature. Almost everyone trying to find that Mexican number. Like, is it wet bulb? temperature, dew point, heat index. So many temperature words. Right, right. But... Long story short, there is no magical number.

Because climatic heat is after all just one of the several factors that results in the hot human body. The critical thing here is your own core temperature. And you can overheat when it's just normal hot out if you are wearing clothes that aren't breathable or if you're sick and you didn't sleep well and your immune system's down. or if you haven't had enough water to drink before you head out. So again, there is no like one-size-fits-all recommendation here. No magical solution. No magic solution, right.

And this training is just one part of a larger strategy for extreme heat management. Eugene LeVar, that chief heat officer in Arizona that we heard from earlier, he thinks it's super important for people to remember that. When you look at acclimating to heat or extreme heat, it doesn't remove the risk for heat-related illness and death. Right. The risk is always still there, and there are limits to how much we can push this heat tolerance, even if we can improve it. Exactly, Rachel. But hopefully this is helpful for some of our listeners. You know, I know that I've been bolder about going out in the heat while listening to my body and also better about hydrating. And I also really now appreciate my sweat. So I'm really grateful that it's helping to keep me cool.

Yeah, here at Shortwave, we are not afraid of a little. sweat. So thanks, Ping, for bringing this to us. Thank you. All right, shortwavers, if you like this episode, consider following us on the podcast platform you're listening to This On. That way, you never miss another episode. And hit us up. We love hearing what science is on our listeners' brains and hearing what you want us to cover in a future episode. Our email is shortwave at npr.org. This episode was produced by Hannah Chin and edited by our showrunner Rebecca Ramirez. Ping and Han,

Anna checked the facts. Quasi Lee was the audio engineer. Beth Donovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Rachel Carlson. Thanks for listening to Shortwave, the science podcast from NPR.