Evaluation of a Field Expedient Technique for Sweat Sample Collection

This series of laboratory experiments was conducted to evaluate a potential field expedient sweat collection technique polyethylene arm bags and to observe the Sweat rate and electrolyte losses of human sweat glands during thermal stimulation. The development of the methodology in this report has resulted in a technique that offers 1 a clean skin surface prior to sweat sample collection 2 a known skin surface area inside the arm bag, 3 quantitative recovery 97.3 of sweat electrolytes, and 4 sweat electrolyte concentrations which agree well with values reported by other laboratories. Polyethylene arm bags were found to induce changes in the local forearm microenvironment when compared to OPEN arms increases in skin temperature, relative humidity, sodium excretion, and potassium excretion were observed. In spite of these changes in local microenvironment, this technique is useful as a relative measure by day-to-day or hour-to-hour changes in sweat collection techniques, such as large sample size, ease of use and field portability. Measurements such as sweat electrolyte losses during exercise in the heat, or sweat rates during heat acclimatization, are feasible with this technique. Keywords include sweat rate sweat electrolytes sodium potassium skin temperature rectal temperature relative humidity body surface area.