An estimation of mineral losses through arm sweat of preadolescent children.

Balance studies were conducted to determine the effects of three levels of nitrogen intake on the loss of nitrogen through sweat in preadolescent boys and girls. During the studies, the losses of calcium, iron, magnesium, manganese, potassium, sodium, and zinc were determined in the arm sweat of the subjects. Sweat from the forearm was collected in a polyethylene bag for 1 hr on three different occasions. Using the concentrations of nitrogen in the arm bag and in the whole body collection and the concentration of minerals in the arm bag, the total body loss of minerals were estimated. Losses of minerals through sweat, expressed as a percentage of intake, ranged from 0.12 to 1.10%. Under conditions of these studies, sweat losses of the essential minerals were not a significant factor in estimating total losses.