Is It Safe to Work Out In a Heat Wave?
You might be surprised by what experts have to say.
Crazy high temperatures from a potentially deadly heat wave are expected to begin today. More than 85 percent of the population will see temperatures above 90 degrees Fahrenheit this weekend, CNN reports, and more than half will see temperatures higher than 95 degrees. That's why 195 million Americans were put under a heat watch, warning, or advisory as of this morning.
When it's this hot and sticky out, the last thing you probably want to do is tackle a workout in the park—and that's a good idea for your safety, too. "Working out in excessive heat makes your body work much harder than it normally would,” Narinder Bajwa M.D., a cardiologist in Sacramento, CA tells Shape. “In order to stay cool, your body diverts a lot of the blood from your muscles to your skin. This puts even more stress on your muscles, forcing you to use more energy, which can be dangerous."
And it’s not just the heat itself that puts your body at risk; humidity also plays a role. “Not only does humidity make it hard to sweat, but your sweat also evaporates at a slower pace," Dr. Bajwa says. "This makes it very hard for your body to cool down and can cause you to overheat and exhaust easily." (Related: How Hot Should It Really Be In Hot Yoga Class?)
While all these things are concerning, Dr. Bajwa says it isn’t necessary to avoid working out in the heat completely, as long as you are taking the right precautions.
For starters, he suggests being mindful of the time of day you choose to workout. “Get out there early,” he says and considering shortening your workout, too. “If you’re a generally active person, it doesn’t really matter if you’re running, weight training, or taking a yoga class outside,” he says. “What is important is that you limit the total amount of exercise you’re doing to avoid overexerting yourself." If you're not in great health or new to working out, he suggests avoiding working out outside during hot days completely. (Related: What Running In the Heat Does to Your Body)
Your clothes matter, too. “Lighter color clothing will help reflect heat, and cotton will help the evaporation of sweat,” Dr. Bajwa says. “Don’t overlook moisture-wicking running shirts and shorts either. Their high-tech material can really help keep you cool. And always wear a cap. Keep turning and adjusting it to guard your face and neck against the sun." (Related: Breathable Workout Clothes and Gear to Help You Stay Cool and Dry)
One of the most important things to keep in mind? Hydration. “Drinking water is so important, especially when you’re faced with temperatures in the triple digits,” Dr. Bajwa says. “The heat causes your body to sweat more than usual, which can quickly lead to dehydration. If you know you’re planning to work out outside on a hot day, start increasing your water intake the day before and obviously drink plenty of extra water the day-of.” (Here are more ways to protect yourself from heat stroke and heat exhaustion when exercising outside.)
And rather than loading up on sports and energy drinks, Dr. Bajwa suggests sticking to plain water during a heat wave. “Water is the easiest to digest and working out in excessive heat can make you feel nauseous,” he says. It’s also important to avoid alcohol, coffee, and soda, he explains, since they can all lead to dehydration.
But while it is possible to work out in the heat safely, it’s also important to know your limits. “Listen to your body,” Dr. Bajwa says. "If you’re getting light-headed or dizzy, it’s time to stop. Another symptom to look out for is cramping. It usually means that your body is getting close to developing heat-related complications and you should call it quits immediately."
At the end of the day, heat-related illnesses caused by exercise are largely preventable. Take these basic, but important, precautions and your routine shouldn't get completely sidelined.