"It's not always easy for the average person to know the difference," says Benjamin Barankin, MD, a dermatologist in Toronto and a member of the American Academy of Dermatology.
Excessive sweating, or hyperhidrosis, can be a warning sign of thyroid problems, diabetes or infection. Excessive sweating is also more common in people who are overweight or out of shape.
The good news is that most cases of excessive sweating are harmless. If you are worried about how much you sweat, here's information to help you decide if you should see a doctor for a medical diagnosis.
What Is Excessive Sweating?
If you just sweat more than other people when it's hot or you're exerting yourself, that's not usually a sign of trouble. Sweating is a normal reaction when your body's working harder and needs to cool itself down.
"There are natural variations in how people sweat, just as there are variations in other bodily functions," says Dee Anna Glaser, MD, vice chair of the dermatology department at St. Louis University and president of the International Hyperhidrosis Society. "Some people start sweating more easily than others."
True excessive sweating goes beyond the normal physical need to sweat. If you have hyperhidrosis, you may sweat heavily for no reason -- when it's not appropriate to the circumstances.
"Let's say that the temperature is mild, and you're not anxious, and you don't have a fever, and you're just watching a movie with your family," says Glaser. "If you're sitting there sweating profusely, that's not normal."
Barankin says that there are two basic types of excessive sweating: localized hyperhidrosis and generalized hyperhidrosis.
Localized Sweating: Primary Focal Hyperhidrosis
The most common cause of excessive sweating is called primary focal hyperhidrosis. This form of hyperhidrosis affects about 1% to 3% of the population, and usually starts in childhood or adolescence.