The girl next to you is drenched and you're barely perspiring. Are you working hard enough?
Photo: Kate Jacobs/Getty Images
Whether you break a sweat the moment the treadmill starts moving or you 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 enough or too much. 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?
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. "That heating can come from external sources like the weather in Florida or the heat generated from muscle activity during exercise."
What makes some people sweat more than others?
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, genetics can also have an impact on how much you sweat, says Jason Karp, Ph.D., exercise physiologist, run coach, and personal trainer, explaining that some people have more functioning sweat glands than others. Physical fitness also influences how much you sweat, and surprisingly, the fitter you are the wetter you'll be. "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." (Learn how to protect yourself against heat exhaustion and heat stroke during the hot summer months.)
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 burn the same number of calories in hot yoga as you would in the studio's air-conditioned room. (BTW, you should learn the art of hydration during a hot fitness class.)
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 to Brett Romano Ely, M.S., a doctoral candidate in human physiology at the University of Oregon.
How much sweat is appropriate during a workout?
One size doesn't fit all when it comes to sweating. Stop worrying about 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 with low airflow, your sweat will evaporate more slowly, which can make 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, Ely suggests trying a heart-rate monitor instead. You can also simply monitor your breathing or use the trusty rate of perceived exertion (how hard are you working on a 1 to 10 scale) to measure your intensity.
When does sweat become "excessive"?
Sweating a lot can be concerning and even a little embarrassing, but it's rarely a real medical problem. There may be cause for concern 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.)
Some people can have "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."
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. 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.
What can you do about sweat and body odor?
Even if you don't fall into the "excessive" sweating category but feel uncomfortable about your level of sweat, Dr. Smith says it may be time for intervention beyond the typical antiperspirant. There are options as minor as "clinical strength" over-the-counter antiperspirants that include higher levels of the compound responsible for temporarily blocking sweat ducts. From there, you may want to try prescription-strength formulations.
If you're specifically concerned about sweating too much during workouts 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. Endeavor Athletic gear not only manages your body heat, but their NASA-certified antimicrobial fabric will also control odor for more wears before you wash. Athleta claims you can wash their "unstinkable" line of gear less often without fear of it being, well, stinky. If your favorite brand doesn't offer anything anti-smell but you'd really love to do less laundry, check out Defunkify's Active Odor Shield. Created by Dune Sciences, which was cofounded by a chemistry professor at the University of Oregon, this laundry product allows users to pre-treat any athletic gear and wear it (apparently sans smells) up to 20 times between washes.
For more serious sweat concerns beyond antiperspirant and clothing, "the list of choices for treating excess sweating has gotten better and better over the years," says Dr. Smith. These include oral medications, Botox injections to reduce sweat in specific areas of the body, and even a device called miraDry that uses electromagnetic energy to destroy sweat glands.
But these more invasive options might not be the best option if strenuous exercise is part of your regular routine, he says, as reducing sweat production to localized areas could limit your ability to cool the body during intense activity.
Is it possible to not sweat 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.
Bottom line? If you're not pouring buckets like the woman 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—listen closely—the amount you sweat doesn't have anything to do with the number of calories you burn.
"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.