Does Sweating Burn Calories?

It sounds logical—but let's unpack this.

You're dripping with sweat after a hard-charging workout session—so does all that sweat mean you're burning more calories than usual? It kind of makes sense; perspiring a lot clearly means you're exerting yourself, and that requires extra energy. But does sweating really burn calories? To unpack the science and get answers, we took it to the experts.

What Causes Sweating

First, let's get into the purpose of perspiring: Your body sweats not to burn calories but to protect you from overheating. "Sweating is the way in which we cool the body during exercise or other heat stress," Thad E. Wilson, PhD, a professor in the department of physiology at the University of Kentucky College of Medicine, told Health. (Dr. WIlson's research focuses on sweat glands and skin blood flow.)

It might be hard to believe—especially when you're deep in a HIIT workout—but exercise itself doesn't stimulate sweating, said Dr. Wilson. Rather, exercise triggers an increase in internal temperature, which ultimately tells your body that it's time to sweat to cool down.

More Sweat Doesn't Mean More Calorie Burn

Basically, sweating on its own doesn't affect how many calories you burn. True, it does take energy to physically transport the ions that allow for water to move into glands to get secreted as sweat, said Dr. Wilson, but not much. In other words, some energy is needed in the process of sweating, but not enough to make a huge difference in the way you feel or what you weigh.

Sweat is only an indication that your body has lost water, not body fat, exercise specialist Gabbi Berkow, a certified personal trainer who has her MA in exercise physiology, told Health.

Physical activity in general burns calories. The more intensely you use large muscle groups, the more calories your body will utilize—and the more heat (and sweat) your body will generate, said Dr. Wilson.

This calorie burn is most significant during an aerobic workout versus a weight-training workout. But if you're doing a weight or interval workout and resting in between sets, you might find that you have to towel off less. "That doesn't mean you didn't get a good workout, burn calories, or build strength—it just means your body temperature didn't rise as much," said Berkow.

Everyone Sweats at Different Rates

Just because you're sweating so much you could mop the floor while your friend is barely glistening doesn't mean much. "There are huge individual variations in the ability to sweat," said Dr. Wilson. If you're acclimated to hot weather, you'll likely sweat more initially because your body knows how to efficiently cool itself. Different people start sweating at different temperatures, too.

Keep in mind that sometimes the body sweats too much, which is the case for people who have a medical condition called hyperhidrosis, according to Yale Medicine. In hyperhidrosis, the body's 2 to 4 million sweat glands are overactive, causing profuse perspiration at times when others would sweat lightly (if at all). People with the condition sweat a lot even when weather is cool or physical activity levels are low. A healthcare provider can help identify treatments that can help.

The Bottom Line

How much you sweat is an inaccurate way to measure calorie burn. "Sweating buckets does not necessarily reflect a great workout," said Berkow. "Sweating a lot means your body became very hot from the workout and needs to cool off."

Still don't buy it? Here's an experiment: Go out at 2 p.m. in the sun on an unseasonably warm day, and you'll likely sweat more than that same walk in unseasonably cold, dark weather—but you'll burn basically the same amount of calories.

If you really want to know how hard or intense you're working out, monitor your heart rate. That can take some special equipment, like a heart rate monitor, health tracker, or app.

You can monitor your heart rate by checking the pulse rate either at the carotid artery in the neck or the radial artery at the wrist, per the National Library of Medicine's Medline Plus. Count the number of beats for 10 seconds and multiply by six to get the heart rate in beats per minute.

If those aren't available to you, then score yourself on the Rate of Perceived Exertion (RPE) scale, suggests Berkow. All you do is rate how difficult the workout is on a 1-10 scale. You won't know exact numbers, but you will be able to compare different workouts and get a sense of when you're taking it easier than usual and when you're killing it.

Whatever your sweat level, just remember that sweat level does not equate to more calories burned. But in general, the more intensely you exercise, the more calories your body will burn—and the more heat (and sweat) your body will release.

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