Everyone perspires, and we all sweat more during the summer. But some people perspire excessively all year. Sweaty palms can sabotage a job interview with a soggy handshake. Wet armpits can make some guys change their shirts two, three, or even four times a day. And a moist smile can make a first date the last.
Although it's not a major illness, excessive sweating is far from trivial. In fact, it can be very embarrassing, and it can interfere with healthy interpersonal relationships. Call it by its medical name, hyperhidrosis, because it's a problem that deserves respect.
Sweating is both normal and necessary. It's one of the ways the body sheds the heat that results from metabolism.
The other way is through conduction. Heat from the skin is carried into the surrounding air. When the air is hot, it's hard to dissipate heat by conduction. When the air is humid, sweat won't evaporate, making perspiration an ineffective way to get rid of heat. So the discomfort of summer is not due to heat or humidity, but to both.
When you're at rest, most of your body's heat comes from your liver, heart and muscles. But when you exercise, your muscles increase their metabolic activity; heat production increases 20 times. As a result, physical activity turns on your sweat glands even in cool weather. And when it's hot out, you can lose up to a quart and a half of sweat per hour. If you let yourself get dehydrated, though, your body will turn off the sweat faucet and your temperature will soar. That's why it's crucial to drink enough water whenever you work out, and why good hydration is particularly important during the dog days of summer.
Without sweating, we'd burn up. But people with hyperhidrosis sweat more than is necessary to regulate body temperature. Excessive perspiration comes in two forms.
Generalized. When heat, humidity and exercise trigger sweating all over the body, it's a normal response to thermal stress. But whole-body sweating can also be a sign of various medical conditions, such as:
Localized. In localized hyperhidrosis, the excess sweating is confined to the palms of the hands, soles of the feet and armpits. Underlying diseases are rarely the cause. Instead, common triggers include intense emotion (particularly anxiety) and strong odors or flavors (particularly spicy foods, citrus fruit, coffee, chocolate, and apples). Often, though, it's not possible to pinpoint the cause of localized hyperhidrosis. But in all cases, heat makes the problem worse.
Because generalized hyperhidrosis has so many possible causes, you should first get a medical evaluation to rule out or identify any underlying problems. Localized hyperhidrosis doesn't usually result from a medical condition, so you don't need a detailed check-up.
Once your doctor has cleared your overall health, you can tackle the sweating itself with these steps.
Because every case of excessive perspiration is different, I can't tell you exactly how to stay dry this summer. But even if I can't provide specific advice, I can offer a generic tip for excessive sweating: Stay calm and, if possible, cool.
Harvey B. Simon, M.D. is an Associate Professor of Medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the founding editor of the Harvard Men's Health Watch newsletter and author of six consumer health books, including The Harvard Medical School Guide to Men's Health (Simon and Schuster, 2002) and The No Sweat Exercise Plan, Lose Weight, Get Healthy and Live Longer (McGraw-Hill, 2006). Dr. Simon practices at the Massachusetts General Hospital; he received the London Prize for Excellence in Teaching from Harvard and MIT.