How to Run a Race When It’s Hot Outside

Here are some tips for running strong, even when the weather isn’t on your side.

With races consistently back on the calendar, even sweltering circumstances won’t stop runners from pinning their bibs on. Here’s what to do to stay safe and still maximise your performance.

Before the raceNo one wants to start a race already sweaty, but that can happen if the temperatures are hot enough. There’s a clear link between lowering your body temp before a hot race and your performance, according to a scientific review published in 2012 in the journal Sports Medicine. In fact, the scientists discovered an average performance boost of 3.7 percent from pre-cooling—that translates to 55 seconds in a 25:00 5K.

“When you’re cooler at the start, you’re in a better position to maintain what we would call your performance physiology,” explains Oliver Gibson, a senior lecturer in exercise science at Brunel University London and lead author of a recent review of heat alleviation strategies published in the journal Temperature. “Your heart rate will be lower because your body temperature isn’t quite as high, and you’re preserving the amount of blood that can go to the muscles instead of the skin for cooling.” It also puts you further away from the individual point where the heat is going to provide you with a real physiological challenge, he adds.

Wearing ice packs on your thighs can also help with that pre-cooling effect. Athletes who stuffed ice into their shorts during a 30-minute warmup finished a 5K time trial an average of 85 seconds faster than they did with no pre-cooling in a 2015 study published in The Journal of Strength and Conditioning Research.

“What you’re doing with ice is blunting the body temperature increase, and reducing the change physiological—especially cardiovascular—response to the heat,” says Gibson. That’s especially relevant during a warmup; yes, it’s still crucial to prepare for a race performance, but the intensity can be scaled way back in the summer, and should be done in the shade to keep your muscles from getting too warm.

While it’s probably not feasible for a recreational runner to be toting an ice vest into the corrals (since you don’t want to run the race with it), you can get similar benefits from bringing a slushie or frozen water with you. Drinking an ice slurry lowered pre-exercise body temperature and increased submaximal endurance running time in the heat, a 2010 study in Medicine & Science in Sports & Exercise found. Translation: Runners could go for an average of 50 minutes before they had to stop, compared to only 40 minutes after drinking a cold beverage.

“Drinking something really cold is a good approach to keeping body temperature down because a cold drink goes directly inside the stomach and cools you from the inside out, whereas ice packs and vests cool from the outside in, which is more difficult to achieve,” says Gibson. Plus, you won’t feel bad tossing a drink versus a vest when the start gun goes off.

During the race

Cooling down during exercise is less about lowering your internal body temperature and more about keeping it from rising, says Doug Casa, Ph.D., Chief Executive Officer of The Korey Stringer Institute, which provides research on exertional heat stroke prevention. “Your goal is to stay away from 40 degrees celsius, because once you hit that, your body starts to enact defense mechanisms—like decreasing intensity—to keep you from overheating,” he explains. “The longer you can stay away from that temperature, the better your performance will be.”

Olympic bronze medalist Molly Seidel was roasted by sister Izzy with the music choice in this Instagram reel, but her method of dousing herself in ice mid-run is a solid one. Cooling the neck was shown to help you run farther in the heat, according to research published in 2011 in Medicine & Science in Sports & Exercise, and some runners also target the shoulders and chest. The key is in the surface area: “The more skin that you can get cold water on, the more beneficial it will be versus focusing on a specific body part,” says Casa.

That’s one of the reasons you’ll see runners dashing through misters and sprinkles along race courses. Fanning and misting the face can reduce an athlete’s rate of perceived exertion, according to a 2004 study published in the European Journal of Applied Physiology.

“The face has got quite a dense nervous system, so you get that sense of perceptual cooling,” says Gibson, “but there are also a ton of capillaries in the face, which are ultimately the things you want to cool down because they contain the blood that’s going to return back to the body.” So not only does this method cool the surface of the skin, but it helps cool the circulating blood.

Your head is another area that plays a huge role in body temp; putting ice on your head allows for the water to trickle down, cooling your neck and back as well. “Again, it’s about surface area,” says Casa. “Runners have limited options for connecting cold with their body while maintaining their pace,” he explains.

And, as important as hydration is in a hot race, you’d actually be better served by dumping that cup of water from the aid station on yourself versus drinking it if your goal is cooling down, according to a 2016 study in Temperature. Don’t do that in lieu of drinking, but think about grabbing two cups at the aid station—one for your mouth and one for your body.

After the race

While the most effective option to cool down after a scorching hot race is to immediately immerse yourself in a cold-water bath, that’s not always the most realistic option. But post-cooling applied directly after exercise improves subjective recovery, since it lowers the symptoms of delayed onset muscle soreness after 24 and 96 hours of recovery, a 2016 study published in the journal Temperature found.

Similar to during the race, applying cold water to as much of your body as possible will help bring your body temp back down, says Casa—think cold towels, pouring water on your clothes and letting them air dry, or dunking your face in a tub of water. If you can find a fan, stand in front of it and use it like a natural AC. When that air flow hits your sweaty clothes, you get the same evaporation effect that cools you when you sweat, says Gibson.

If you aren’t able to do any of that, “the most critical tool for cooling post-race is to escape from the source of heat,” says Gibson. Get into the shade, under a tent, in a car with AC—anything that gets you out of direct exposure to the sun. And if you feel nauseous, spacey, headachy, are seeing spots, or feel off otherwise, get yourself to a medical tent STAT. Those are signs of heat illness, something that can affect even the most seasoned runners.

But don’t let high temps and humidity turn you off from summer and fall races—just go into it with a strategy and listen to your own body and you’ll be able to beat the heat.

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