Comparison of sweat rate measured by a pouch collector and a hygrometric technique during exercise.
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% VO2max on a cycle ergometer at an ambient temperature of 35 degrees 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 x cm-2 x 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 x cm-2 x 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.
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Laboratorie de Physiologie et de Psychologie Environnementales, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France.
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Candas
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D000328:Adult; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D012881:Skin Temperature; D013055:Spectrophotometry, Infrared / Q000379:methods; D013546:Sweating / Q000502:physiology*