Abstract
Cutaneous receptors stimulated by iced-water immersion of one hand will increase sympathetic nerve activity to palm skin in the non-immersed contralateral hand and reduce blood flow, reflecting upon a decrease in skin surface temperature under constant ambient environment. To test the hypothesis that gender might affect the contralateral vasoconstrictor response, we analyzed the spatiotemporal pattern of palm skin surface temperature during iced-water immersion for 10 min using thermography in eight males and eight females. As soon as the left hand was immersed into iced-water, palm skin temperature in the non-immersed right hand quickly decreased in all subjects, particularly in the periphery of the digits and palm. The reduction in skin temperature was short-lasting in 63% of males and 38% of females, while it lasted throughout immersion in the remaining subjects. The average decrease in palm skin temperature was not significantly different between males and females, although it tended to be greater in males. Mean arterial blood pressure significantly increased and heart rate decreased during immersion in males, whereas no substantial cardiovascular changes were observed in females. Cold sensation was well coincident with the appearance of the reduction in the palm skin temperature. Taken together, it is suggested that cutaneous cold stimulus increased skin sympathetic nerve activity to the non-immersed hand and reduced skin blood flow and that gender difference in the contralateral vasoconstrictor response was denied, because the time course and magnitude of the decrease in palm skin temperature were not different between males and females.
