Perspiration

Perspiration, watery fluid secreted by the skin as a means of reducing body temperature. Sweating is common in hot climates, after exercise, and in the resolution of fever; the evaporation of sweat allows the skin and thus the body to be cooled. Humid atmosphere and high secretion rates delay evaporation, leaving perspiration on the surface. Excessive fluid loss, and of salt in cystic fibrosis, may lead to sunstroke. Most sweating is regulated by the hypothalamus and autonomic nervous system, but there is also a system of sweat glands, especially on the palms, that secretes at times of stress. Hyperhidrosis is a condition of abnormally profuse sweating.

See also: Skin; Temperature, body.