Sweat, also called perspiration, is a salty liquid produced by the sweat glands. Sweating is an essential function that helps the body stay cool. Sweat is commonly found under the arms, on the feet, and on the palms of the hands.

How much you sweat depends on how many sweat glands you have. A person is born with about two to four million sweat glands. The glands start to become fully active during puberty. Women actually have more sweat glands then men -- the men's glands are just more active.

Because sweating is the body's natural way of regulating temperature, people sweat more in when it's hot outside. People also sweat more when they exercise, or in response to situations that make them nervous, angry, embarrassed, or afraid.  

If sweating is accompanied by fever, weight loss, chest pain, shortness of breath, or a rapid, pounding heartbeat, talk to a doctor. These symptoms may indicate an underlying problem, such as hyperthyroidism. Excessive sweating may also be a symptom of menopause.

See also: 

sweating - absent

sweating - excessive

• Warm temperatures
• Fever
• Menopause
• Overactive thyroid gland
• Low blood sugar
• Infection
• Cancer (sweating at night without an obvious cause)
• Emotional or stressful situations
• Exercise
• Spicy foods (known as "gustatory sweating")
• Drugs, including antipyretics, some antipsychotics, sympathomimetics, caffeine, morphine, alcohol and thyroid hormone
• Withdrawal from alcohol or narcotic pain killers

After an episode of sweating, a person should:

• Wash the face and body
• Change clothes and bed sheets
• Replace lost body fluids by drinking plenty of water
• Slighly adjust room temperature to prevent additional sweating

• There is prolonged, excessive, and unexplained sweating.
• Sweating is accompanied or followed by chest pain or pressure.
• Sweating is accompanied by weight loss or most often occurs during sleep.

Sweat. Dorland's Medical Dictionary. 28th ed. Philadelphia, Pa: WB Saunders Company; 1994:1617.

Drip or Dry? Dermatology Insights. 2002;3(1):12. Available online at: http://www.aad.org/NR/rdonlyres/66F5C772-07E5-4839-A8D1-868108C58F99/0/DIspring02.pdf#page=12 (accessed May 12, 2005).