Physical regulation of temperature in Eskimos

¹ Department of Physiology, University of Buffalo School of Medicine, Buffalo, New York, and Department of Physiology, Arctic Aeromedical Laboratory, APO 731 Seattle, Washington

Temperature regulation of Eskimos and non-Eskimos, exclusive of shivering, was compared over a range of controlled conditions that produced near-maximal sweating (room temp., 35 C) to maximal cutaneous vasoconstriction (23 C air or 33 C water bath). The Eskimos consistently produced 15–20 kcal/m²/hr more heat at rest. This may or may not be cold adaptation. In air warmer than 28 C their surfeit of heat resulted in higher tissue conductances, warmer skin, and greater sweating. In cooler air and 33 C water, the physical conductance of heat through tissues of the Eskimos remained 60% greater and resulted in warmer skin or a greater fall of rectal temperature. This can be accounted for on physical grounds, since the Eskimos had 1 cm less subcutaneous fat than did non-Eskimos. The value of high metabolism and high tissue conductance to fully clothed Eskimos would appear to be reflex vascular convection of heat to distal extremities, since average skin temperatures under their clothing are comparable to those of unclothed Eskimos in room temperatures exceeding 28 C.