Effect of sweat loss on body fluids

Abstract

Six healthy men were studied under normal conditions and after dehydration caused by sweating produced 1) in a sauna at 80 C, 2) by hard muscular work at 18 C, and 3) by mild exercise at room temperature 38 C. The dehydration period lasted for 2.5@#X2013;3.5 hr. Sweat was collected in impermeable plastic bags around the forearm. Body weight, Evans blue space, and apparent inulin space were determined before and about 90 min after the dehydration period. The average decrease in body weight was 3.1 (4.1%), 3.1, and 3.5 kg for 1, 2, and 3, respectively. The reduction in apparent inulin space was 1.4, 0.2 and 1.3 liters, respectively. The decrease in Evans blue space paralleled the reduction in apparent inulin space. In the three conditions no significant differences were found in calculated total loss of electrolytes. Water liberated from combustion of fat and carbohydrates plus water previously stored with glycogen can account for up to 1.1 liters of the intracellular water loss during the hard exercise (2). The additional water loss from the cells is discussed in light of electrolyte shifts. dehydration; intracellular fluid; extracellular fluid; plasma volume Submitted on January 20, 1964