Athletes kick, run, cycle, jump, flip and otherwise push themselves to their physical limits during the Olympic Games this summer. For some athletes, these events can push the limits of their heat tolerance.

“(The combination of heat and humidity can really overwhelm an athlete pretty quickly,” says). Dr. Francis O’Connorprofessor of military emergency medicine and medical director of the Consortium for Health and Military Performance at the Uniformed Services University in Bethesda, Md. He is co-author of a new article in the medical journal YAMA on heat-related illness in athletes.

O’Connor says that strenuous heat stroke is most likely to occur in competition. “In Paris, you’re going for a medal. Or if you’re a soldier trying to finish your course, or you’re trying to get a (personal best) in a marathon — you’re going to push, and you can push yourself into a problem,” he says.

Heatstroke is a very serious condition where a person’s core temperature is generally 104 degrees or higher and they are in an altered mental state; it can lead to organ failure and death. It can happen even if you don’t do competitive sports, but stay out in the heat for too long without proper hydration.

One of the best methods to stave off problems, says O’Connor, is heat acclimation, also known as heat training. The idea involves controlled exposure to heat stress, which causes changes in the body that help it cope with hot, humid conditions. In fact, the Olympic Medical Department published one guide that recommends warm-up in advance for athletes coming to Paris.

Warm-up training isn’t just for competitive athletes. It is recommended for people in the military and those who work outdoors in hot weather. It may even be useful for generally healthy members of the public, says O’Connor. “People shouldn’t be afraid of the heat,” he says. “We can develop and add an adaptive response to help us succeed in the heat. But it needs to be controlled.”

Done right, heat training can help people stay a little more comfortable in the long, intense heat stretches that mark extraordinarily hot summer 2024 and future heat waves are expected more frequently due to climate change.

A solution with caveats

There are two important points to note before exploring the subject of heat training.

One is that it is not for everyone. Heat-related illness is serious and can be fatal. And it can come quickly.

“Everyone needs to be aware and self-assess and work with their healthcare provider, coach and others to factor in any personal considerations,” says Eugene Liver, an epidemiologist and chief heat officer for the notoriously hot state of Arizona. And when people work long hours in the sun, or otherwise exert themselves greatly in the heat – it can lead to heatstroke, which is considered a serious medical emergency.

Two is that the ultimate goal for our planet, climate scientists say, is not to say, well, it’s getting hotter and hotter so it’s up to individuals to figure out how to deal with it. The researchers emphasize that as climate change continues to drive up temperatures, the ultimate global strategy to curb the heat is to reduce the pollution — largely from burning fossil fuels — that is responsible.

But in the meantime, it’s quite warm outside. The last few weeks the temperatures have in Las VegasNev., and Delhi in India has topped 120 degrees.

Healthy adaptations to heat

Heat and health experts say that gentle, gradual exposure to heat can induce healthy adaptations that help the body better tolerate hot days. “There is data to suggest that it can improve overall circulation, improve your immune system and cardiovascular health,” says Jason Kai Wei Leedirector of the Heat Resilience and Performance Center at the National University of Singapore Medical School.

Research on heat acclimation has focused on athletes, the military and outdoor workers, Lee says. Most people may not be up as long in hot weather as those groups, he says. But the same principles apply. Gradual increase in the dose of summer heat, with cooling breaks in between, can facilitate acclimatization.

It’s hard to come up with a one-size-fits-all regimen because a person’s heat tolerance depends on factors like age, baseline fitness and whether their immune system is healthy, Lee says.

Sweating a lot is key

A person’s susceptibility to overheating can vary from day to day, based on factors such as poor sleep, fatigue and illness, says O’Connor of the Uniformed Services University.

“When I evaluate warfighters who have had heat stroke, anecdotally, the vast majority of them had an underlying infection,” he says. “Colds, gastroenteritis, sinus infections, periodontal disease, blisters — these things automatically raise your body temperature,” he says, so adding hot ambient temperature or heat stress on top of that is more likely to tip a person into the realm of heat illness.

Your risk of overheating also depends on what you’re trying to do in the heat—go for a walk with a friend or a long, fast run—along with external factors like what the temperature is like and whether they can reliably get anywhere. cool down.

And since the body relies on sweat evaporating to cool itself, how much someone is pre-hydrated, what they’re wearing, and how humid it is all matter.

But the point is, you can’t improve your tolerance without breaking a sweat. “You have to build up, but at a minimum you have to get out there and sweat,” says O’Connor. “If you don’t induce any sweating, it’s not enough stress to induce the physiological adaptations.”

Take it easy

The advice from National Singapore University’s Lee is to take it slow and easy, with long rest breaks in between. “The broad, five strategies we advocate would be aerobic conditioning, heat acclimation, work-rest cycling, cooling, and then hydration — in that order,” he says.

Lee says it’s preferable to acclimatize before the hottest days. A suggested protocol, he says: “Exercise every other day gradually in a warm environment. On Monday, go for a 15-minute walk, rest on Tuesday, go for a 30-minute walk” on Wednesday, rest on Thursday—you get the idea.

During several weeks of regular heat exposure, the body begins to adapt to cool down more efficiently. “The very obvious one is an increase in your ability to sweat,” says Lee. As the sweat evaporates, it cools the body.

Circulation improves and blood volume increases, so the heart does not have to work as hard to pump blood through the body.

The gradual heat exposure will also help people learn how their bodies respond to the heat and to drink water when they’re thirsty and slow down when they’re hot, Lee says — all of which help keep core temperatures down.

Always watch for signs of overheating

Research shows that it is required a few weeks exposure to get used to training in the heat – and maybe just a week or so out of the heat to lose it.

So while heat training may help some, it won’t be a cure for extreme, sudden spikes in heat, which are becoming more common with climate change.

Instead, it is part of a larger strategy for how to approach the hot days safely. “When it comes to heat, stay cool, stay informed, stay hydrated and wise, and stay connected by checking on your friends, family and neighbors throughout the heat season,” says Arizona’s Livar.

And if you’re out in the heat – look out for signs of heat illness in yourself or those around you. “If you have an excessive headache, excessive fatigue—this is really a time to tell yourself that you need to step back, cool down, slow down,” says O’Connor.

And look closely for signs of cognitive changes that might indicate heatstroke.

“If you’re out with a friend and you notice that friend is less communicative, maybe has an off-kilter gait, seems confused, has a change in personality — that’s concerning,” he says.

Copyright 2024 NPR