A modified anaerobic method of sweat collection.

In an attempt to devise a method for collecting large volumes of thermally induced sweat with less epidermal contamination and evaporative water loss, we developed an anaerobic sweat collector by using a sheet of polyethylene film placed over a thin layer of Vaseline and paraffin oil on the skin. To test the validity of the new method, sweat samples collected every 5 min from the new collector (sweat A) were compared with those obtained from a second collector using no oil (sweat B) and scraped sweat for concentrations of adenosine 3',5'-cyclic monophosphate (cAMP), protein, glucose, urea, lactic acid, calcium, sodium, potassium, and cholesterol. The concentration of sweat ingredients in scraped sweat was often far greater than could be expected from evaporative water loss alone. When compared with sweat A, sweat B also had higher concentrations of these ingredients in the initial samples, indicating epidermal contamination, which was especially marked in cAMP, protein, urea, cholesterol, and calcium. Concomitant with a rise in plasma glucose following the administration of a glucose bolus, the sweat glucose significantly increased, indicating the plasma as a major source of sweat glucose. We conclude that the new sweat collector is instrumental in collecting large volumes of the cleanest possible human sweat.