Even if Bikram yoga is your personal idea of hell, sweating through an outdoor workout session during the dog days of summer may actually be a big fitness advantage.
Sure, the cool, crisp weather of autumn will make you want to strap on your sneakers and get outside. But pushing yourself in the summer heat could help improve your performance in running, cycling, or other cardio activities. As long as you take the right precautions, workouts in hot weather may give you a boost if you’re training for an endurance event, such as a marathon, Tough Mudder or some other sort of weekend warrior-style event. Hot-weather training may even eclipse high-altitude training when it comes to improving your performance.
Here's what you need to know to sweat it out safely.
How Heat Can Boost Exercise Performance
There's some science behind how heat can help improve fitness levels: Researchers from the University of Oregon tracked the performance of 12 very high-level cyclists (10 male, two female) over a 10-day training period (with two days off in the middle) in 100-degree heat. Another control group did the exact same exercise regimen in a much more comfortable, 55-degree room. Both groups worked in 30% humidity.
Researchers discovered that the cyclists who worked through the heat improved their performance by 7% (a noticeable and significant amount in cycling), while the control group did not show any improvement. What surprised researchers most was that the experimental group not only showed that they had achieved a level of heat acclimation, but the training also helped them to function better in cooler environments.
Here are the magic numbers you need to know to maximize your heat acclimation:
101. The number of degrees Fahrenheit you need to elevate your core body temperature during training sessions, says Minson.
60. The number of minutes you want to have that elevated core temperature maintained during your heat training to make sure that you’re truly getting the heat acclimation benefits, says Minson.
5 to 10. The number of days you need to train in the heat. “To really heat acclimate the way we’re talking about, someone has to really go out and exercise in the heat for five to ten days, with pretty significant exposure at times,” Minson says. Just be sure to follow warm-weather precautions to keep from overly stressing your body.
Read on: Safety tips for hot workouts
Safety Tips for Hot Workouts
Elevating your core body temperature so much that you pass out (or worse!) during a workout is not going to score you any points in the fitness department, so it's up to you to know your limits. “People just need to be wise enough to listen to their bodies,” says Cedric Bryant, Ph.D., a fitness expert for the American Council on Exercise. “It isn’t a ‘no pain, no gain’ situation.”
Try these tips to stay safe when the heat is on.
Drink up. You obviously sweat more as it gets hotter and more humid, so you’ve got to make sure you’re replacing all those fluids as you run, bike, or do other workouts in such extreme weather. Dr. Bryant recommends consuming 16 to 24 ounces of water a couple hours before exercising in hot temperatures. Past that, he says to take in another six to eight ounces of fluids every 15 to 20 minutes of exercise. If you’re looking to do something moderate for less than an hour, water should be fine, but anything more intense will require sports drinks to get those carbohydrates and electrolytes, he says.
Mind the humidity. Humidity is also a huge factor to take into account, and it’s something Minson’s study didn’t test for. “The principle way in which the body cools itself during exercise is through sweat,” Dr. Bryant says. “It hits our skin's surface and it evaporates to cool the body. In a humid environment, you don’t experience as much of that evaporative cooling effect because the environment is already pretty saturated with fluid.” Bryant says to consider moving activity indoors on days that are extremely hot and humid, since it just makes the environment particularly stressful on your body.
Don't go overboard. Finally, know that you can still be in good shape without heat acclimating. Minson and Bryant each say they only recommend it to very fit, competitive athletes who need to be ready for weather extremes and/or want to get an edge.
Still, if you’re a serious recreational athlete planning to run a marathon or compete in some sort of weekend-long competition, it’s better to get your training in when the heat is on and be ready in case you’re up against 95-degree weather with high humidity at your next event. There, you might feel tempted to push your body past its limits, but in training, you have the chance to improve your heat acclimation and conditioning over time without pushing yourself too hard. Make sure to wear breathable clothing and don’t go overboard on intensity during the first couple hot workouts.