Why Am I Not Sweating When Working Out?

Are you just not putting in enough effort? Or is the class too easy for you? Could be. But according to Hospital for Special Surgery exercise physiologist Matthew Accetta, MS, CSCS*D, the most likely culprit is simple: dehydration.

“While sweat level definitely varies person to person, most of the time when somebody isn’t sweating it’s because of dehydration,” he says. “The body isn’t full of fluids, so it’s trying to hold on to whatever it has.”

So if you know that you’re usually a sweater but today that’s just not the case, be sure to hit the fountain and fill up your water bottle—and keep drinking extra for 24 hours after your workout. Accetta also suggests creating (or revising) a “hydration plan” before your next session: “Not drinking enough water in a day isn’t all that unusual,” Accetta says. “I know I’m guilty of it at times, and my clients can be, too.” But if it becomes a regular habit, you’ll want to find a way to kick it before it causes any serious complications.

If not dehydration, then what?

Of course, not drinking enough isn’t the only reason you may be perspiring less than usual.

The weather is an obvious one. Because sweat is one important way the human body controls internal temperature, sweat levels tend to go up or down depending on your workout environment. The cooler the air around you, the less you need to sweat—and vice versa. Accetta adds that humidity (or lack thereof) can be another factor. “Air that has a higher humidity content will make you start sweating faster,” he says.

Accetta also notes that people tend to sweat more as they get older—starting as early as puberty. “As the body gets older, there’s more of a need to thermoregulate and get back to homeostasis,” he says. “That’s why older individuals sweat more and children tend to sweat less.” So if you’re the youngest in your workout class, it’s not out of the question that you also might be the driest.

Keep in mind that, in rare instances, certain medications or thyroid issues can actually be what’s preventing you from sweating as much as you should to maintain optimal body temperature. If a noticeable lack of sweating persists even in the hot weather when you’re fully hydrated, make an appointment with your primary care provider to get everything checked out.

Do I really need to “sweat it”?

In fitness culture, visible sweating can be seen as a badge of honor: proof that you’re pushing yourself incredibly hard, or as evidence that long-term gains are indeed happening at that moment. So if, for whatever reason, you don’t sweat as much as you feel like you should, it can feel like something might be wrong with you.

Not true, says Accetta. Not only do sweat levels differ widely from individual to individual, “there’s definitely such a thing as excess sweating, where people who hydrate more than others have excess fluid on board that causes excess sweating.”

If you know that you’re well-hydrated—and that you’re setting challenging-but-manageable fitness goals for yourself—try not to break a sweat over it.

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