US EPA

4843819 

Technical Report 

The Trace Mineral Losses in Sweat 

Consolazio, CF; Nelson, RA; Matoush, LO; Hughes, RC; Urone, P 

1964 

S 

284 

The importance of trace mineral loss in human sweat in relation to normal intake and minimal daily requirement was evaluated. In an environmental chamber at 37.8 degrees-C and 50 percent relative humidity, three healthy males were tested for four 4 day periods. The test activity was 30 minutes per day on a bicycle ergometer. Sweat rates were determined by measuring weight changes, adjusting for water intake and weight loss due to urinary and fecal output. Urine and fecal samples were taken twice daily. Daily food intake of 3,283 kilocalories was monitored and mineral balances were computed on each subject for each period. The subject's trace mineral losses during increased heat exposure were decreased after acclimatization. The mineral losses included zinc (7440666), selenium (7782492), copper, (7440508), cobalt (7440484), iodine (7553562), strontium (7440246), molybdenum (7439987), nickel (7440020), lead (7439921), and chromium (7440473). Iodine excretion in urine was considerable, ranging from 356 to 380 micrograms per day, although iodine intake was not computed. When sweat losses were included, lead, nickel, copper, and cobalt were in negative balance. The authors conclude that trace mineral losses in sweat should be assessed in computing human balance studies.