Pflügers Archiv : European journal of physiology
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This study examined the effect of local heating on the blood flow of the finger or forearm in male subjects in an environment of 35 degrees C--40% (r.h.). One hand or forearm was immersed in a water bath the temperature of which (Tw) was raised by 1 degrees C every 10th min from 35 degrees to 43 degrees C, while the other hand or forearm was kept at a constant Tw of 35 degrees C. Blood-flow (BF) was measured by venous occlusion plethysmography, using temperature-compensated mercury-in-Silastic strain gauges. ⋯ At TwS of 42 degrees -43 degrees C, finger BF in the heated hand greatly increased after an initial transitory fall. In the forearm skin, however, no such vasoconstriction in response to local heating was observed. All this suggests that a rise in skin temperature to above the core temperature produces paradoxical vasoconstriction in the finger, which may be a mechanism to reduce heat gain through the hand heated locally at higher temperatures.