Sweat Analysis for Water Loss Estimation during Physical Exercise


Quantitative estimation of water loss during physical exercise is important because dehydrations can impair both muscular strength and aerobic endurance. A physiological indicator for total body water (TBW) loss could be the concentration of electrolytes in sweat. It has been shown that electrolyte concentrations differ after physical exercise, depending on whether water loss was replaced by fluid intake or not. However, this observation has not been explored for its potential to estimate TBW loss quantitatively.

Therefore, we collected sweat samples during two hours of physical exercise without fluid intake. A statistical analysis of the analyzed measurements showed significant correlations between chloride concentration in sweat and TBW loss (r = 0.41, p < 0.01), and between sweat osmolality and TBW loss (r = 0.43, p < 0.01). The estimation of TBW loss using a Gaussian Process regression resulted in a mean absolute error of 0.49 liter. Although this precision has to be improved for usage in the field, the results suggest that TBW loss estimations could be realized based on sweat analysis.


The data is available at PhysioNet.