Effects of wearing two different forms of garment on thermoregulation in men resting at 10 degrees C

We have compared the human thermoregulatory responses and clothing microclimate temperature when the body core-shell ratio was changed by wearing two different forms of garment. Each was worn for 160 min at an ambient temperature of 10 degrees C and a relative humidity of 50% by six healthy males in the supine posture. One garment covered the whole body area except for the face (long-sleeves: L-S), the other covered the central body area alone (half-sleeves: H-S). Major findings are summarized as follows: 1) Rectal temperature was kept higher by H-S than L-S even though L-S showed higher thermal resistance values. 2) The standard deviation of rectal temperature was smaller in H-S. 3) Trunk skin and clothing microclimate temperatures were also kept higher by H-S. We suggest that the reduced level of rectal temperature in L-S might be ascribed to a different pattern of venous return originating in the mechanisms of the counter-current heat exchange system: the venous return from the periphery into the thoracic and abdominal areas being cooler in L-S than in H-S.