Whole-Body Sweat Rate during Graded Exercise Testing and Sweat Rate during Prolonged Exercise

Abstract

2143 Sweating capacity has been measured by pharmacological induction (cholinergic agents) and during prolonged exercise. A recent study showed correlation between sweat rate (SR) induced by pilocarpine through iontophoresis and SR during graded exercise testing until exhaustion (GET). Therefore, it is interesting to know whether GET could be a reliable predictive index of the sweating capacity in others exercising situations. PURPOSE: Measure the whole-body SR during GET and during a prolonged exercise (PRO) in the same individuals. Methods: Nine healthy male volunteers (22,3 ± 3.6 yrs; 176.3 ± 5.9 cm; 69.2 ± 7.6 kg; body surface area (BSA): 1.85 ± 0.1 m2; VO2peak: 57 ± 12 mLO2.kg−1.min−1) performed two exercises bouts in thermoneutral environment (18.4 ± 0,4 °C and 19 ± 0.6 °C WBGT, GET and PRO, respectively). The GET consisted of 25W of power increments every 2 min on a cycle ergometer until exhaustion. During PRO the volunteers cycled 2 hours at a constant power (500 kcal.h−1). Whole-body SR was calculated by the difference of the body mass after exercises, divided by BSA and by the duration of exercise. Results: The SR in GET (4.1 ± 1.3 g.m−2.min−1) was similar to SR in PRO (4.1 ± 1.0 g.m−2.min−1) and there was a significant correlation between the SR during GET and PRO (r = 0.79, r2 = 0.62, p = 0.01). Conclusion: The PRO stimulated the sweating in a proportional way to GET, which suggests that the measurement of sweating during a graded exercise testing could be a predictive index of the sweating capacity in a thermoneutral environment. Supported by: CAPES, CNPq, FAPEMIG, SNE