Sweat: 5 Things You Didn’t Know

April 03, 2017

Melanie Kingsley, M.D., a dermatologist at Indiana University Health, explains what does (and doesn’t) make us perspire and what to do if you’re always the sweatiest person in the room.

Fact #1: How much you sweat is luck of the draw.

Genetics may play a role, but otherwise there’s little rhyme or reason why some people perspire more than others, says Dr. Kingsley. “It’s not dependent on someone’s gender or size, though people who are heavier might sweat a little more when they’re active because they’re carrying more weight,” she explains. Still, that doesn’t make overweight or obese people more prone to hyperhidrosis—the medical term for excessive sweating. “People with hyperhidrosis sweat even when they’re just sitting still,” Dr. Kingsley says.

Sometimes, a medical condition such as diabetes, gout, and hyperthyroidism causes excessive sweating, as can certain medications like antidepressants and stimulants.

Fact #2: The best time to apply antiperspirant is at night.

This is a particularly helpful strategy for people who sweat a lot. “By applying antiperspirant before bed, you’re giving it a chance to soak into your sweat glands when you’re not active,” Dr. Kingsley explains. If you only use antiperspirant in the morning, you’re already active and may sweat it right off (though it is wise to apply another layer in the morning.)

Fact #3: Sweat itself doesn’t smell.

Odor is only produced when sweat combines with bacteria on your skin, which is found primarily in the creased areas of your body (such your armpits and groin) and on your feet, which, when stuffed into socks and shoes, provide a moist environment for bacteria to flourish. “For people who have very strong-smelling sweat, dermatologists can prescribe clindamycin lotion, which kills the bacteria that causes odor,” Dr. Kingsley says.

Fact #4: There are two types of hyperhidrosis.

The condition, which typically emerges in adolescence, may only affect one or two parts of the body, often the armpits, hands, or feet. Others have generalized hyperhidrosis and sweat excessively all over their body. While the condition isn’t dangerous, it can have a significant impact on a person’s life, according to Dr. Kingsley. Some people may have to change their clothes several times a day because they perspire so much, or they may avoid social situations because they’re ashamed of their sweating.

Fact #5: Hyperhidrosis is treatable.

Dermatologists have a variety of tools they can use to tame excessive sweating. “The first line of treatment is to try a prescription-strength antiperspirant called Drysol, which contains twenty percent aluminum chloride to block sweating,” Dr. Kingsley says. Next steps include Botox injections (ideal for localized hyperhidrosis) and miraDry, which uses microwave technology to kill sweat glands in the underarms. People with generalized hyperhidrosis may benefit from anticholinergic medications such as Robinul, which shuts down the sweat glands.

One treatment Dr. Kingsley doesn’t recommend is endoscopic thoracic sympathectomy, in which doctors surgically eliminate part of the nerve supply to the sweat glands in the skin. “The outcome isn’t great because the body compensates for the loss by sweating excessively from other parts of the body,” she explains.

-- By Jessica Brown

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