Competition Between Sweat Glands and Kidneys for Salt and Water in Man

¹ From the Department of Physiology and Health Service Research Unit, University of Illinois, Urbana, Illinois

The rate of sweating and the electrolyte composition of the sweat during work in the heat were determined in the human forearm using sweat collected in a latex cuff from a single subject. Sodium and chloride concentrations of sweat varied directly with effective room temperature, rectal temperature, skin temperature and rate of sweating. The potassium concentration of sweat varied inversely with these factors. In acute water deprivation the threshold for sweating was elevated and the rate of sweating depressed. Sweating markedly diminished urinary output of water, sodium, chloride and potassium.