Sweat rate and prediction validation during high-altitude treks on Mount Kilimanjaro

摘要

This study measured sweat rates (msw) during high-altitude summer treks on Mt. Kilimanjaro to evaluate the efficacy of a recently developed fuzzy piecewise sweat prediction equation (Pw,sol) for application to high-altitude conditions. We hypothesized that the Pw,sol equation, adjusted for the barometric pressure (Pb) decreasing steadily at high altitude (Pw,sol+Alt), would allow for a more accurate prediction of msw than Pw,sol unadjusted for altitude (Pw,so1sl Fifteen men (43 +- 16 yr; 80 +- 22 kg) and seven women (46 +- 16 yr; 77 +- 18 kg) wearing hiking clothes (clo -1.15; clothing evaporative potential = 0.27) and carrying light loads (9 +- 2 kg), were studied during morning and afternoon treks (-2-3 h) while ascending from 2,829 m to 3,505 m. After each trek, msw was measured with specific biophysical parameters at 15-min intervals. During the trek day, Pb progressively declined (530 to 504 Torr), as solar radiation and ambient temperature (°C) rose transiently. During all treks, msw ranged from 68 to 393 g-m~(-1)>-2h~(-1) (0.14 to 0.79 1/h For each subject, derived Pw,so1Sl and Pw,sol+Alt model outputs accu-rately predicted the morning and afternoon average msw within a root mean square error of 0.145 1/h. No differences were found between Pw,so1Sl and Pw,sol+Alt values. In conclusion, we report the first msw measured during outdoor high-altitude activities and determined that Pw,so1Sl equation can be used to predict fluid needs during high-altitude activities without alterations for lower Pb. This model prediction provides a valid water planning tool for outdoor activities at high altitude up to 3,500 m.