Not so long ago, my preference for working out in a chilled space had an easy solution: I opted out of hot yoga. (I’m quick to schvitz and prefer to glisten versus drip.) But lately, the heated workout has edged toward the norm, with a wave of warm classes ranging from barre and Pilates to HIIT, cycling, and strength training. Their popularity is underscored by the idea that hotter means better. Now, choosing to bake while exercising is apparently proof of athletic rigor, even spiritual toughness. And forgoing the heat seems wimpy.
It’s all made me (just a tad!) defensive. I had a suspicion that the craze was, well, a lot of hot air, and it turns out, experts agree: A sweaty workout does not equal a successful one. And there’s little reason to shun a room-temperature fitness class. You can get every bit as good of a workout, if not a better one, at 70 degrees as you can at 100, regardless of how much you sweat. That moisture is simply an indication that your core or skin temperature has gone up, which can happen in scenarios that involve zero physical activity, like lounging in a sauna.
There is a relationship between sweat and workout intensity, Craig Crandall, PhD, director of the Thermal and Vascular Physiology Laboratory at the University of Texas Southwestern Medical Center, tells SELF. If you compare a person who’s walking on a treadmill in a 70-degree room with someone sprinting in the same room, the latter person will drip more—but if one of these people is in a hot room, it’s apples to oranges. “Now, that person’s sweating is not just a factor of how much heat they’re generating via exertion, but rather a combination of that and the heat they’re getting from the environment.” That means they’ll get damper faster without pushing any harder.
Besides the sweat factor, proponents of heated workout classes often point to the fact that they feel extra-exhausted afterward as evidence that it’s doing more. And it’s true that stressing your body via exercise and heat takes an additional toll, J. Luke Pryor, PhD, associate director of elite athlete performance at the University of Buffalo’s Center for Research and Education in Special Environments, tells SELF. “The heart has to increase blood flow to dissipate the heat as well as provide more oxygen and nutrients to our muscles.” As a result, you’ll experience a sharper spike in heart rate during a class in a hot studio, which is what tires you out faster. Over time, your body will grow more adept at this response: You’ll sweat more quickly and profusely to keep your temp down, meaning your heart rate won’t shoot up as high, Dr. Crandall says.
That’ll let you power through lengthier heated sessions—an acclimation response that can come in handy if you’re, say, preparing for a race in a sweltering locale. (Though if you really want to boost your performance for a specific activity, training in that activity is going to prep your body better than acclimating to the heat in a completely different modality.) But otherwise, exercising occasionally in the heat isn’t going to make a difference for your overall cardiovascular health or fitness versus doing similar workouts in a cooler space, Dr. Crandall says.
If anything, the heat will slow you down and diminish your performance, he adds. Consider how if you’re wiped out, drenched in a pool of sweat halfway through a class, you might not pedal as hard or squat as deep for the rest of it. Or if you were planning to run 10 miles on a treadmill, you may only make it eight in a muggy gym. That means you could wind up getting less cardiovascular load in the heat, Dr. Crandall explains. So no, a heated class won’t increase your fitness gains over an air-conditioned one, nor will you burn more calories or lose weight faster with hot workouts (if that’s what was prompting you to turn up the heat). Any pounds shed within the course of a class just reflects water loss. And dehydration—which can be more likely with hot workouts—can impair performance on its own too.
Though experts say heated workout classes aren’t usually dangerous for most folks, given the body is equipped to adapt, the combo of heat from the environment and what you’re producing with movement can push you toward heat-illness territory, especially if you’re not well-hydrated, Rathna Nuti, MD, a board-certified family and sport medicine physician in Dallas, tells SELF. Same goes if the room is ultra-humid: This can keep sweat from evaporating, which limits its cooling powers.
So if you do opt for a warmed-up workout, you’ll need to hydrate more than usual both before and throughout, Dr. Nuti says. And don’t be afraid to take a break if the heat starts to get to you, she adds, especially if you feel woozy, nauseous, or headache-y, or are hyperventilating—all signs of heat exhaustion. In this scenario, you’ll want to trade the stifling room for AC, and drink plenty of water. (And if your symptoms persist longer than an hour, or you pass out, be sure to seek medical care.)
For the most part, though, the heated workout isn’t so much capital-B Bad as it is unnecessary and overhyped—a trend that I’ll happily bypass. The main perk of jumping or pumping in a steamy setting is, again, the ability to perform better and more safely in the heat over time. As Dr. Crandall puts it, “the only negative to working out in a chilled space would be if you decide to go to the state fair in Texas in September—you won’t be able to tolerate the heat as well as somebody who routinely exercises in the heat.”
There may also be a psychological advantage for select masochists. Maybe you enjoy the torture of physical movement in an environment that leaves you sopping-wet and gasping for air. If that’s a sign to you of a good workout, the added heat might keep you coming back for more, which can help with building an exercise habit, Dr. Pryor says. But contrary to popular belief, working out doesn’t have to make you feel like death to be worth it. And for everyone else who, like me, doesn’t seek out suffering? Having to subject yourself to a room that’s hot as hell could deter you from taking a class altogether—leading you to miss out on all the benefits of exercise that are just as abundant in mild temps.
Related:
- 3 Things to Do If the Heat Starts Making You Feel Physically Ill
- Is Salty Sweat Something to Worry About When You Exercise?
- The Best Hot Yoga Mats for Your Next High-Temp Flow
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