HEMIHIDROSIS AND CUTANEOUS BLOOD-FLOW IN THE HEAD AND HAND

1. The present study examined whether hemihidrosis, the unilateral inhibition of sweating during external pressure application to the surface of the body, was accompanied by decreased cutaneous blood flow in the head and hand of 7 hyperthermic subjects. 2. The subjects were warmed by 40 degrees C water immersion to a tympanic temperature ca 0.8 degrees C above resting. They were then laid in a supine position and covered with a sleeping bag. Pressure application was obtained by positioning the subjects laterally, with their weight supported by the lateral gluteal and axillary regions on a 0.075 x 1.5 m edge. This position gave an average applied pressure of 5.33 kPa. 3. The lateral pressure decreased sweating on the ipsilateral temple by 22% (p < 0.05) illustrating a hemihidrosis, but changes of ipsilateral cutaneous blood flow were not significant. 4. During pressure application hemihidrosis was not observed on the hand, nor was inhibition of the hand cutaneous blood flow evident. 5. In conclusion, ipsilateral head hemihidrosis was not accompanied by a decrease in cutaneous blood flow on the head and hemihidrosis was not evident for the hand. For hyperthermic patients a supine or prone rather than a lateral lying position is suggested to avoid hemihidrosis and the associated decrease of sweating and heat loss.