How Much Should You Really Sweat During a Workout?

Whether you break a sweat the moment the treadmill starts moving or feel more of your neighbor's sweat spraying you in HIIT class than your own, you may have wondered what's normal and whether you're sweating too much — or even too little. In reality, everyone sweats at different temperatures and at different exertion levels. But what causes some of these differences and when is it time for concern? And is there a way to not sweat so much during exercise?!

What Makes Some People Sweat More

First and foremost, know that sweating is completely normal. "Sweating is a normal, healthy response to heating of the body," says Stacy R. Smith, M.D., a dermatologist in Encinitas, California. "That heating can come from external sources like the weather in Florida or the heat generated from muscle activity during exercise," he explains. But even if it's normal, you may still wonder, "why do I sweat so much when I work out?"

To outsmart sweat, it helps to know exactly what it does. When this mix of water, salt, and other minerals evaporates from your skin, it cools you down, allowing your body to maintain its core temperature. "There are two kinds of sweat: eccrine, a thin liquid that occurs all over the body when it's hot outside or when you exercise, and apocrine, a thick secretion found mainly at your underarms," says Dee Anna Glaser, M.D., president of the International Hyperhidrosis Society and a dermatologist in St. Louis. Apocrine is tied to odor and is typically related to stress.

Although your diet, health, and emotions may play a role, how much you sweat is mostly determined by genetics, as is where you sweat. The most common spots are your underarms, palms, soles, and forehead because they have the highest density of sweat glands. (The underarm area is home to a bacteria that digests sweat and produces B.O.) Sweat patterns are highly individual, however: For instance, your back might perspire first because the glands there are quickest to respond to your brain's signals in times of heat or stress, explains Dr. Glaser.

There are other lifestyle factors that can play into how much you sweat. While gender and age play a part in perspiration, a higher fitness level, increased exercise intensity, larger body size, hotter environmental temperature (indoors or outdoors), lower ventilation or airflow, less humidity, and non-breathable clothing will all lead to higher sweat levels, says Brett Romano Ely, M.S., an assistant professor in the department of sport and movement science at Salem University.

It probably doesn't come as much of a surprise that hydration levels and sweat go hand in hand. If all other factors are equal, inadequate hydration on a regular basis can cause one person to sweat less than another, says Dr. Smith. But drinking more than what's necessary to hydrate before, during, and after exercise isn't going to leave you more drenched than someone who adequately hydrates. Certain medications, such as hormonal birth control, may also have side effects that cause you to sweat more or less, so consult your doctor or pharmacist if you think that might be the issue.

Beyond hydration and medication, physical fitness also influences how much you sweat — and surprisingly, the fitter you are, the wetter you'll be, says Jason Karp, Ph.D., an exercise physiologist and running coach in San Diego. "The reason why fitter people sweat more — and also earlier into a workout — is because the body becomes more efficient at cooling itself," says Karp. "People view sweating as a bad thing, but it is the evaporation of sweat that enables you to not overheat," he adds.

So, the answer to your burning question of "why do I sweat so much when I work out" might just be that you're physically fit. But while more sweat is an indication of physical fitness, don't be fooled by fitness classes that crank up the heat. As long as you're able to work out at your normal intensity level, you'll get just as good a workout in hot yoga as you would in the studio's air-conditioned room.

How Much You Should Sweat During a Workout

One size doesn't fit all when it comes to sweating. So if you barely break a sweat, stop worrying that you're not giving enough during your workout, because exertion isn't always directly related to sweat production, says Ely. You can go for a bike ride on a cool day and barely sweat, regardless of how many hills you climbed, she says. In high humidity or low airflow, your sweat will evaporate more slowly, making you feel like you are sweating more. And in the opposite conditions, your skin can feel dry, but in reality, the sweat is just evaporating much more quickly.

If you feel like you need to sweat to prove to yourself that you're working hard enough, try a heart-rate monitor instead, suggests Ely. You can also simply monitor your breathing or use the trusty rate of perceived exertion (aka how hard are you working on a one-to-10 scale) to measure your intensity.

When Sweat Becomes "Excessive"

You should probably stop sweating about how to not sweat so much during exercise, these experts agree. Sweating a lot can be a little embarrassing, but it's rarely a real medical problem. There may be cause for concern, though, if you're sweating out electrolytes and fluids faster than you can rehydrate. "Sweating a lot can cause dehydration, which can impair metabolism and decrease blood flow to muscles (since water loss through sweating decreases blood volume), so it can be dangerous if you don't replenish the fluid through drinking," says Karp. (Dehydration is just one of the things that can make your workout feel harder, and not in a good way.)

There's a possibility you may suffer from a rare condition called hyperhidrosis, where the body sweats more than is necessary for cooling, says Dr. Smith. "This excess sweating can lead to skin irritations, social difficulties and embarrassment, and substantial excess wear and tear on clothing," he notes. People with hyperhidrosis often report sweating for no apparent reason in cool environments, having to bring extra shirts to work or school as they become wet/stained before the day is over, or adjusting their schedule so that they can go home and shower before going out in the evening after work.

Only a doctor can officially diagnose excessive sweating or hyperhidrosis, but simply put, "excessive sweating is often defined as any sweating that interferes with normal daily activities," says Dr. Smith.

What You Can Do About Sweat and Body Odor

Even if you don't fall into the "excessive" sweating category but feel uncomfortable about your sweat level, it may be time for intervention beyond the typical antiperspirant, says Dr. Smith. Options include opting for a "clinical strength" over-the-counter antiperspirant, which has higher levels of the compound responsible for temporarily blocking sweat ducts, and prescription-strength formulations.

If you're specifically concerned about how to not sweat so much during exercise, but it's not an issue when you're just going about daily routines, opt for workout clothes with wicking properties to avoid that wet feeling and to extend the life of your gym wardrobe a little longer. Some apparel brands even promise clothing with "anti-stink" technology. Lululemon offers select items featuring Silverescent; silver stops stink-causing bacteria from reproducing. Endeavor Athletic gear not only manages your body heat, but their NASA-certified antimicrobial fabric can also control odor for more wears before you wash. Athleta claims you can wash their anti-odor "unstinkable" line of gear less often without fear of it being, well, stinky.

For more serious sweat concerns or for people with hyperhidrosis, the good news is the list of choices for treating excess sweating has gotten better and better over the years, says Dr. Smith. This includes oral medications; prescription-strength antiperspirants such as Drysol; injections of Botox or Dysport, which temporarily deactivate your sweat glands; and even a device called miraDry, which uses electromagnetic energy to destroy sweat glands. In addition to Botox, doctors often recommend laser hair removal for your underarms. "I find that it leads to less sweat production and decreases odor, too, because your hair accumulates more bacteria than your skin," says Mary Lupo, M.D., a dermatologist in New Orleans.

But these more invasive options might not be the best option if strenuous exercise is part of your regular routine, as reducing sweat production to localized areas could limit your ability to cool the body during intense activity, says Dr. Lupo.

What About Not Sweating Enough?

When people talk about issues surrounding sweat production, it's mostly about sweating too much. But you don't want to be on the flip side of this equation, either. Sweat is healthy and necessary to regulate body temperature. Plus, remember that it's a sign of stellar physical fitness, too.

So, when should you worry that you're not sweating enough? "There's no cause for concern if someone doesn't seem to sweat a lot unless it leads to heat exhaustion or heat stroke," says Karp. In rare cases, not sweating enough can be a sign of anhidrosis (or hypohidrosis), a disease in which sweat glands don't function properly.

If you're not pouring buckets like the person next to you on the stair climber and you're wondering if you're working hard enough, you probably don't need to worry. Just keep at it because — reminder! — the amount you sweat doesn't have anything to do with the "success" of your workout.

"There is no relationship between sweating and calories burned," says Craig Crandall, Ph.D., professor of internal medicine at the University of Texas Southwestern Medical Center. You can run the exact same route in the summer and the winter, and although you'll sweat more in the heat, the number of calories you can expect to burn will be virtually identical, he says. There are just too many factors involved that influence sweat production, he adds. And although you do lose "weight" when you sweat, it's just water weight and this can lead to dehydration.

The Bottom Line: How to Not Sweat So Much During Exercise

First, choose the right product: antiperspirant. Deodorants curb odor, not moisture; antiperspirant-deodorant combos tackle both. Some people opt for deodorant because their sensitive skin reacts badly to antiperspirants. Others avoid it because of rumors that aluminum-based compounds — the active ingredients in most antiperspirants — have been linked to cancer or Alzheimer's disease, but clinical studies show no evidence of such a connection.

Whether you use a solid, a gel, or a roll-on doesn't matter, but the time at which you apply the stuff does: Derms recommend putting on antiperspirant at night before bed and then reapplying it in the morning for the best results. "For your antiperspirant to work, it has to get into the sweat glands and block them," explains David Bank, M.D., a dermatologist in Mount Kisco, New York. "Overnight, you're calm and cool and your skin is completely dry, so a much higher percentage is going to be absorbed," he says.

You can apply antiperspirant anywhere that sweat surfaces, but watch for irritation, especially on sensitive spots such as your chest. For the area under your boobs, dust on baking soda when your skin is clean and dry. "Baking soda is antibacterial and anti-inflammatory. In addition to drying up moisture, it prevents irritation," says Dr. Bank.

To absorb sweat on your scalp, use dry shampoo, and to keep feet dry, try sweat-wicking inserts such as Summer Soles (Buy It, $8, amazon.com), suggests Dr. Glaser. To prevent down-there sweat, opt for an absorbent powder designed for that area. Your workout wear also makes a difference: Invest in high-tech synthetic fabrics that feel airy and wick moisture away from your skin.

If it takes you forever to cool down and dry off post-workout, jump into as cold a shower as you can stand (eucalyptus optional). "Anything that lowers your core temperature will help you stop sweating sooner," says Dr. Winger. Short on time? Simply stick your feet under the spray. Humidity, which prevents sweat from evaporating, may also be part of the problem.

The only real fix for how to not sweat so much during exercise in these conditions is to take it easy. "If it's a very humid day and you're out running, slow your pace," recommends Dr. Winger.