Comparison of Sweat Rate Measured by a Pouch Collector and a Hygrometric Technique During Exercise

Abstract

Measurements of local sweat rate (back) determined with a closed-pouch collector made of polyethylene (110 cm2) were compared with those obtained from a ventilated capsule using an infrared photometric hygrometer technique. Eight young male subjects underwent three exercise sessions each for 60 min at 45% [Formula: see text] on a cycle ergometer at an ambient temperature of 35 °C and 35% relative humidity. When the onset and transient sweating periods (0-20 min) are excluded from calculations, the difference between the mean values obtained by the collector and the sweat capsule during the 20-60 time period is only 0.06 ± 0.04 mg • cm−2 • min−1 (5%). Although a significant correlation (r = .74, p < .05) was obtained between methods, individual differences in sweat-rate measurements varied on average ±0.22 mg • cm−2 • min−1 (±19%). Designed more specifically for sweat-content analysis, the pouch collector may serve as a satisfactory field method to approximate the local sweat rate and excretion induced by prolonged exercise in a hot environment. Key words: sweating assessment, methodology, thermoregulation, skin temperature