Sweating

Sweating (also called perspiration or sometimes transpiration) is the production and evaporation of a watery fluid, consisting mainly of sodium chloride (commonly known as salt) and urea in solution, that is secreted by the sweat glands in the skin of mammals. Sweating also consists of the chemicals or odorants 2-methylphenol (o-cresol) and 4-methylphenol (p-cresol). In humans, sweating is primarily a means of temperature regulation. Evaporation of sweating from the skin surface has a cooling effect due to the latent heat of evaporation of water. Hence, in hot weather, or when the individual's muscles heat up due to exertion, more sweat is produced. Sweating is increased by nervousness and nausea and decreased by cold. Animals with few sweat glands, such as dogs, accomplish similar temperature regulation results by panting, which evaporates water from the moist lining of the oral cavity and pharynx. Primates and horses have sweat glands in their skin, similar to humans.

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.

Excessive sweating occurs in about 1% of the population. It goes by a variety of names including idiopathic hyperhidrosis (meaning you've got it but we don't know why), essential hyperhidrosis, gustatory hyperhidrosis and diabetic gustatory hyperhidrosis. Hyperhidrosis may be triggered by eating (gustatory) and stress factors such as public speaking or meeting new people. Excessive sweating is just that, an exaggerated response to a situation or stimulus that triggers a normal amount of sweating in most people. Sometimes excessive sweating can be a sign of an underlying disease. In these instances, excessive sweating usually occurs at night or has just recently begun in someone who has never experienced it before. Anyone with a newly onset of excessive sweating or night sweats should visit their family physician to rule out underlying and correctable illnesses.

See your doctor if you suddenly begin sweating more than usual or experience night sweats for no apparent reason. A cold sweating is usually your body's response to a serious illness, anxiety or severe pain. Seek immediate medical attention for a cold sweating, especially if you have symptoms of lightheadedness or chest and stomach pains.