Sweating News Sweating (also called perspiration or sometimes transpiration) is the production and evaporation of a watery fluid, consisting mainly of sodium chloride (the main constituent of "table salt") in solution, that is excreted by the sweat glands in the skin of mammals. Sweat 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 sweat 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 h