ZINC LOSS IN SWEAT OF ATHLETES EXERCISING IN HOT AND NEUTRAL TEMPERATURES

Zinc (Zn) loss from sweat of 9 male and 9 female athletes exercising u nder hot (35-degrees-C, HE) and neutral (25-degrees-C, NE) conditions was examined. Subjects exercised at 50% VO2max on a cycle ergometer fo r 1 hr during each trial. Cell-free sweat samples were analyzed for Zn by atomic absorption spectrophotometry. There was a significant inter action of time, gender, and temperature for whole-body sweat rates (WB SR). WBSR for males were higher during both trials and at each time. W BSR from the second half of exercise were higher than those from the f irst half for both sexes and temperature conditions. Sweat Zn concentr ation was higher in the NE than in the HE, but when the sweat rates we re included, the rate of Zn loss was no different between HE and NE. Z n concentration of the sweat for the first half of exercise was over t wice that of the second half. Sweat Zn concentration of the men was no different than that of the women; however, due to greater sweat rate, men had significantly higher Zn losses. Although total Zn losses are estimated to be relatively low compared to the RDA, exercise at modera te intensities may increase surface Zn losses.