Head temperature modulates thermal behavior in the cold in humans

ABSTRACTWe tested the hypothesis that skin temperature, specifically of the head, is capable of modulating thermal behavior during exercise in the cold. Following familiarization 8 young, healthy, recreationally active males completed 3 trials, each consisting of 30 minutes of self-paced cycle ergometry in 6°C. Participants were instructed to control their exercise work rate to achieve and maintain thermal comfort. On one occasion participants wore only shorts and shoes (Control) and on the 2 other occasions their head was either warmed (Warming) or cooled (Cooling). Work rate, rate of metabolic heat production, thermal perceptions, rectal, mean weighted skin and head temperatures were measured. Exercise work rate was reduced during Warming and augmented during Cooling after the first and second minutes of exercise, respectively (P ≤ 0.04), with the rate of metabolic heat production mirroring work rate. At this early stage of exercise (≤5 min) the changes over time for rectal temperature were negligible a...