Studies on Sweat Losses of Nutrients I. Iron Content of Whole Body Sweat and its Association with other Sweat Constituents, Serum Iron Levels, Hematological Indices, Body Surface Area, and Sweat Rate

Abstract

Whole body sweat was collected in 23 healthy, young adult men during 60 min of profuse sweating in an environmental chamber at 40–45°C and 80–90% relative humidity. Before and after the sweat collection hemoglobin, hematocrit, mean corpuscular hemoglobin concentration, serum iron, and serum chloride were determined. The iron content of cellrich and cell-free sweat was measured by chemical methods and also the content of chloride, calcium, and magnesium of cell-free sweat.

The mean iron concentration of cell-rich sweat was 41.2 μg/100 ml of which 29.8 was found in the cell-free fraction. The corresponding losses per hour were 0.5 and 0.4 mg respectively.

Correlation analysis showed a positive association between iron content of cell-free sweat and serum iron levels after sweat collection, suggesting a probable biological relationship. There was also a positive association between iron content of cell-rich sweat and body surface area. No association was found between iron and the other sweat constituents, hematological indices or sweat rate.

The problem of contamination is discussed and it is suggested that chemical measurement of iron excretion in sweat is reliable if adequate precautions are taken to avoid contamination. The study has confirmed previous findings, which indicate that dermal iron losses may be appreciable under conditions of profuse sweating. This must be taken into account when iron balance experiments are performed.

Key Words:

• Calcium
• chloride
• environmental chamber
• iron
• magnesium
• sweat losses
• unacclimatized men
• whole body sweat