The effect of change in skin temperature due to evaporative cooling on sweating response during exercise

Abstract

 The purpose of this study was to investigate whether there are any effects of skin temperature changes on sweating response in the first few minutes of mild exercise. Six healthy males performed a bicycle exercise at 100 W (50 rpm) for 30 min under an ambient temperature of 23° C (40% RH). Esophageal temperature (T _es), mean skin temperature (T– _sk), local skin temperature at the lower left scapula (T _sl), local sweating rate (M. _sw), and cutaneous blood flow by laser-Doppler flowmetry (LDF) were measured continuously. Although T _sl decreased markedly just after the onset of sweating, T– _sk did not change. M. _sw did not increase constantly in the early stages of exercise, and there was a temporary interruption in the increase of M. _sw. This interruption in sweating was affected by the rate of change in T _sl rather than by the absolute value of T _sl, since there was a positive and significant correlation between the time of the interruption in the increase of M. _sw and the rate of decrease in T _sl (y=6.47x+0.04; r=0.86, P<0.05). The results suggest that sweating response in the early stages of exercise may be influenced by changes in local skin temperature due to evaporative cooling.