Cholinergic sensitivity of the eccrine sweat gland in trained and untrained men.

The purpose of this study was to compare the cholinergic responsiveness of the human sweat gland in trained and untrained men. Eighteen healthy male volunteers (9 trained, 9 sedentary) served as subjects. Pilocarpine concentration vs. sweat rate dose-response curves were obtained from each subject using iontophoresis. From these measurements, maximal iontophoretic sweat rate (SRmax) was determined and correlated with each subject's maximal oxygen uptake (VO2max). The trained group had a significantly (P less than 0.05) greater mean SR max and their mean dose-response curve was shifted up and to the left, as compared to the sedentary controls. Furthermore, VO2max was significantly correlated with SRmax (r = 0.76). These findings suggest that the modification occurring in the human sweat gland after training may include improvements in both SRmax and cholinergic sensitivity, and support the hypothesis that the potentiation in sweating following training is achieved via a peripheral mechanism.