Perspiration Functions in Different Ethnic, Age, and Sex Populations: Modification of Sudomotor Function.

The sudomotor mechanism, wich contributes to tolerating thermal environments, is affected by not only the body temperature, but also sex, ethnicity, exercise training, region, season, and heat adaptation. Aging attenuates the sudomotor function by the decreased peripheral sensitivity to acetylcholine and demyelination of innervating nerves. Women show less sudomotor activity than men. Heat adaptation with sudomotor modification is induced by repetitive physical and/or thermal training. Short-term heat acclimation increases sweat gland activity. Long-term heat acclimation results in a reduction in the sweating response to stimuli. Residents of tropical areas sweat less and more slowly than residents of temperate areas. Short-term heat acclimation enhances the sweating response. Long-term heat acclimation, from seasonal change or migration, diminishes the sweating response. Also, deacclimation can be induced by migration from a tropical area to a temperate area. Body composition, especially brown adipose tissue, and weight affect thermal responses. Further studies should investigate BAT and endocrinal pyrogens as additional factors.