If genius really is 1% inspiration and 99% perspiration, then some of us must be a lot smarter than others. While sweat is a normal human function, a lucky few seem to produce higher-than-normal amounts—especially in the hot summer months. But before you hole yourself up in air conditioning all season, there are a few things you should know about sweat. Here’s the basics on what it is, why it happens (to certain folks more than others), and what you can do if you’re concerned about it.
There are three types of sweat
All sweat is not created equal, says Laure Rittié, PhD, research assistant professor in the department of dermatology at the University of Michigan. And everyone sweats differently: Some people may have problems with all three types of perspiration, while others may really only ever notice one or two.
First, there’s body sweat—the odorless type that pours off you during a workout or when you stand out in the hot sun. This type of sweat exists to help cool the skin and keep the body’s internal temperature as close to 98.6 degrees as possible. You’ll notice it pretty much everywhere, but especially along the forehead and the spine.
Then, there’s perspiration on the palms and soles of the feet. This type of sweat helps increase adherence and grip, says Rittié, and, evolutionarily, it’s the body’s response to a perceived threat. (That’s why some people notice it when they’re feeling anxious.) “When you want to hold onto something, you’ll do better with wet fingers,” Rittié explains. “In the beginning, we didn’t wear shoes, so sweaty feet helped us run or climb when we needed to.”
Finally, there’s sweat that’s emitted from the armpits and the . This is the type that produces so-called body odor, thanks to bacteria living in these places. “We’re not completely sure what the function here is, but we think there’s some pheromone-type of communication going on,” Rittié says. “If one individual in a herd senses danger and starts to emit those strong smells, it could alert others around them.”
Sweating a lot doesn’t mean you’re out of shape
The body begins producing body sweat when it starts to heat up—either externally, from high temperatures, or internally, from muscle exertion (like when exercising). So if you push yourself harder than your body is used to, your body is more likely to kick on its internal air conditioning; that’s why a highly trained athlete may be able to run a 10-minute mile without breaking a sweat, while the same workout may leave a less conditioned person red-faced and drenched.
But the more you train your body, and the more time you spend in hot, humid climates, the more efficient you become at sweating. “The body will adjust and react a little earlier before you get too hot,” says Rittié, “so your sweating will be more spread out over time and across your whole body—rather than building up and releasing all at once, and leaving one big spot on your shirt.”
Yes, that may translate into more sweating overall—just look at any NBA basketball game and you’ll see that even highly-trained athletes sweat a ton—but it’s ultimately a good thing. It means the body is better able to respond to the demands of heat and exercise, and stays cooler as a result.
How much you sweat is largely determined before age 2
Whether you sweat buckets or stay fresh as a daisy on hot days also has a lot to do with genetics. “If one or both of your parents were heavy sweaters, then there is a good chance that you will be too,” says exercise physiologist Michael Bergeron, PhD, President of Youth Sports of the Americas. Men also tend to sweat more than women, he says, although that’s not always the case.
Body composition matters, too: Larger people generally sweat more, because they work harder to carry a heavier load. “But many comparatively small people can sweat tremendously,” says Bergeron. And because muscle generates heat, he adds, people with more muscle mass also tend to sweat more than their leaner peers.
But actually, a lot of how much a person sweats has to do with the first two years of life. That’s when sweat glands are first activated, says Rittié; if they don’t get fully turned on during this period, they likely never will. In other words, a super-active toddler who runs around in the heat will likely develop greater sweating ability (again, a good thing) than one who’s not very active.
Heavy sweaters should hydrate more
“The more you sweat, the more deliberate you need to be about replacing the water your body’s lost,” says Bergeron. When exercising, most adults can comfortably and safely take in about 1.5 liters (a little more than 50 ounces) of water an hour. If you’re sweating more than that amount—you can weigh yourself before and after a workout to find out—you should make up for it by drinking extra water before and after you work out.
Sweat also contains important electrolytes, like sodium, that the body needs to function properly. Most people get enough salt in their diets that they don’t need to worry about this, but if you’re exercising for longer than an hour and really sweating a lot, an can help replace what’s lost.
Rittié also points out that acclimating your body to exercise or to heat—so that you ultimately sweat less—won’t work if you don’t drink enough water on a regular basis. “Staying hydrated before and during exercise will help train your body to fight the heat,” she says. Cold water is best, she adds, “because it helps to cool down your internal organs.”
Prescription treatments may help
Besides staying in shape, wearing , and spending two to three weeks acclimating to the heat, there’s not much people can do about heavy sweating during exercise. (Putting antiperspirant on your hairline or may help curb localized perspiration—but, Rittié warns, when you block sweat glands in one part of the body, others will compensate by working even harder.)
People with excessive day-to-day sweating, however—a condition known as —may have more options. If you’re already using an over-the-counter aluminum-based antiperspirant and it just isn’t cutting it, your doctor may recommend a prescription-strength solution with aluminum chloride. These work best when applied before bed, but can cause skin and eye irritation for some people.
Botox injections and certain types of medications have been shown to block the nerves that trigger sweat production, and may be useful for people who sweat excessively under their arms or on their hands and feet. (If those don’t work, electrical stimulation or even surgery may be considered.) Friction also contributes to sweaty feet, says Rittié, so changing up your shoes and socks—and being sure you aren’t sliding around in them—may help, as well.
If sweating is truly causing a problem in your daily life, talk to your primary doctor or dermatologist about potential solutions. Otherwise, grab your and get outside. Embrace your sweaty self, and try to be thankful your body is doing its job.