Two types of sweat glands can be found in humans: eccrine glands and apocrine glands.[2] The eccrine sweat glands are distributed over much of the body and are responsible for secreting the watery, brackish sweat most often triggered by excessive body temperature. Apocrine sweat glands are restricted to the armpits and a few other areas of the body and produce an odorless, oily, opaque secretion which then gains its characteristic odor from bacterial decomposition.
In humans, sweating is primarily a means of thermoregulation, which is achieved by the water-rich secretion of the eccrine glands. Maximum sweat rates of an adult can be up to 2–4 litres (0.5–1 US gal) per hour or 10–14 litres (2.5–3.5 US gal) per day, but is less in children prior to puberty.[3][4][5]Evaporation of sweat from the skin surface has a cooling effect due to evaporative cooling. Hence, in hot weather, or when the individual's muscles heat up due to exertion, more sweat is produced. 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.
Although sweating is found in a wide variety of mammals,[6][7] relatively few (apart from humans, horses, some primates and some bovidae) produce sweat in order to cool down.[8] In horses, such cooling sweat is created by apocrine glands[9] and contains a wetting agent, the protein latherin which transfers from the skin to the surface of their coats.[10]
^Jessen, C. (2000). Temperature Regulation in Humans and Other Mammals. Berlin: Springer. ISBN978-3-540-41234-2.
^Mack, G. W.; Nadel, E. R. (1996). "Body fluid balance during heat stress in humans". In Fregly, M. J.; Blatteis, C. M. (eds.). Handbook of Physiology. Section 4: Environmental Physiology. New York: Oxford University Press. pp. 187–214. ISBN978-0-19-507492-5.
^Sawka, M. L.; Wenger, C. B.; Pandolf, K. B. (1996). "Thermoregulatory responses to acute exercise-heat stress and heat acclimation". In Fregly, M. J.; Blatteis, C. M. (eds.). Handbook of Physiology. Section 4: Environmental Physiology. New York: Oxford University Press. ISBN978-0-19-507492-5.
^Goglia, G (January 1953). "Italian: Cavia cobaya, Sus scrofa, Equus caballus" [Further research on the branched sweat glands in some mammals]. Bollettino della Società Italiana di Biologia Sperimentale (in Italian). 29 (1): 58–60. PMID13066656.
^McCutcheon, L. Jill; Geor, Raymond J. (1998). "Sweating: Fluid and Ion Losses and Replacement". Veterinary Clinics of North America: Equine Practice. 14 (1): 75–95. doi:10.1016/s0749-0739(17)30213-4. ISSN0749-0739. PMID9561689.