Role of skin temperature in the control of sweating.

In five male subjects tympanic membrane temperature (Tty), rectal temperature, skin temperatures at 12 sites were simultaneously recorded. Local sweating rate was measured at six sites using resistance hygrometry. After steady-state sweating was established, the lower body was heated at ambient temperatures of 50, 60, 70, and 80 degrees C or cooled at an ambient temperature of 29 degrees C while the upper body remained at a constant ambient temperature. During lower body heating or cooling, Tty was maintained constant by the drinking of cold (10 degrees C) or warm (45 degrees C) water. Sweating rate on both upper and lower body surfaces was proportional to lower body skin temperature. The regression coefficients for sweating rate versus mean lower body skin temperature varied from 0.03 to 0.09 mg/cm2.min. degrees C between subjects, but were not significantly different from each other (P greater than 0.05). This study demonstrates an influence of cutaneous thermoreceptors on sweating rate under steady-state conditions.