OBJECTIVETo clarify the seasonal differences of the trace element excretion in sweat, the trace element concentration in sweat and their loss during exercise were compared between summer and winter.

METHODSSweat samples were collected from ten healthy adult males. Bicycle ergometer exercise was conducted by each subject at a heart rate of 140 beats/min for 1 hour, in summer and in winter. Sweat was collected by the arm bag method.

RESULTSConcentrations of major (Na, K, Ca, and Mg) and trace elements (Zn, Cu, Fe, Ni, Mn, and Cr) in sweat tended to be lower in summer than in winter, and significantly lower concentrations of Mg (p<0.01), Na, Cu, and Mn (p<0.05) were found in summer. The sweat volume in summer (0.90 L) was 1.7-fold larger than that in winter (0.52 L) (p<0.01). The amount of loss of each element to sweat calculated from the concentrations in sweat and sweat volume showed no significant difference between summer and winter.

CONCLUSIONSIt is suggested that there was no significant difference in the amount of loss of trace elements in sweat due to exercise between summer and winter.