Pilocarpine-induced Sweat Rate at Rest Versus Whole-body Sweat Rate During Exercise

The purpose of this study was to examine the relationship between pilocarpine-induced sweat rate obtained at rest and whole-body sweat rate during exercise. Eighteen healthy male volunteers (nine trained, nine sedentary) served as subjects. Each subject had his maximum oxygen uptake (O2 max) measured and his forearm peripheral sweat rate determined via pilocarpine iontophoresis. On a separate day, each subject exercised for 30 minutes at 70 percent O2 max, following which whole-body sweat rate was determined. The results showed that O2 max was linearly correlated with both whole-body sweat rate (r = 0.84) and pilocarpine-induced sweat rate (r = 0.83). Furthermore, whole-body sweat rate and peripheral sweat rate were linearly related (r = 0.86). These results suggest that pilocarpine-induced sweat rate can serve as a meaningful index of eccrine sweat gland function during exercise. These findings have implications both on a mechanistic and applied level, and support the hypothesis that the increase in sweating seen following training is achieved via a peripheral mechanism.