EXTREMITY TEMPERATURE RESPONSES TO COLD AFTER AN ARCTIC TREK

Abstract

People who live or work in cold environments often exhibit an adaptation by which they maintain warmer extremities during cold exposure, and a blunted vasoconstrictor response to cold is thought to account for this adaptation. However, the degree to which a given individual develops this response over the course of a prolonged cold exposure appears to be influenced by exposure conditions, e.g., climate, duration, clothing, or activity. In this study, we examined extremity temperature responses to cold in two men (RG, TL) before and after a 109-d ski trek across the Arctic Ocean (average Tair = −21°C). Temperatures were measured on each finger (Tf) and toe (Tt) during 30 min cold (4°C) water immersion. During extremity immersion, room temperature was kept constant (27°C) to maintain similar core and mean skin temperatures during tests before and after the expedition. After the expedition, both men exhibited small but consistent (both hands) reductions in mean Tf response to cold. In contrast, mean Tt was higher in both feet for TL and in the left foot for RG post-expedition, compared to before. These results suggest that the feet, but not hands, developed the blunted vasoconstrictor response and enhanced blood flow during cold exposure. Carrying heavy backpacks and gripping ski poles for prolonged periods might have influenced cold-induced vasomotor responses and blood flow to the hands during the expedition, thereby inhibiting cold adaptation. Similarly, RG experienced numbness in his right leg during the expedition due to backpack and sled waist belts, which may explain the lack of adaptation in this foot. Further research may be warranted to determine the effects of such ergonomic constraints on extremity blood flow during cold exposure.Table: Mean middle digit temperatures (°C) pre- and post-expedition