To examine the effect of work intensity on the regional distribution of sweating and cutaneous vasodilation in relation to aging, 9 young (20-25 yr) and 6 older (65-77 yr) men cycled at 35, 50, and 65% of their maximal oxygen uptake (VO₂max)for 30 min in a controlled climate at 28℃ and 40% rh. During the exercise, there was a significant increase in the heart rate (%HR) relative to the baseline value and rectal temperature (Tre) with increases of work intensity, regardless of group. There were no group differences in the %HR and Tre (except for the exercise at 35 %VO₂max). The percentage in local sweating rate (msw) at each site relative to the sum of msw for all 5 sites (forehead, chest, back, forearm and thigh) increased significantly on the forehead and decreased on the thigh with increases of work intensity, regardless of the group. However, the percentage msw on the thigh was significantly lower in the older men than in the young men for all work intensities, although the percentage msw on the forehead was similar in both groups (except for the exercise at 35% VO₂max). The lower percentage msw on the thigh observed in the older men was due to a lower sweat output per gland and not to a lower active sweat gland density. In general, msw was significantly lower in the older men, especially on the thigh. The percentage change in LDF (%LDF) relative to the baseline value increased significantly between the exercises at 35 and 50% VO₂max, but it did not change between 50 and 65% VO₂max, regardless of age and body site. There were no regional differences in the %LDF in the older men at any exercise intensity. On the other hand, in the young men the %LDF was significantly greater on the forearm than on the forehead and chest in the exercises at 35 and 50%VO₂max, and was significantly greater on the forearm and chest than on the forehead at 65%VO₂max. The older men had a significantly lower %LDF at every work intensity, regardless of body site. These results suggest that there are regional differences in the magnitude of the increase in sweating and cutaneous vasodilation with increasing work intensity in both young and older men. Furthermore, aging affects the magnitude.

DESCENTE SPORTS SCIENCE Vol.20/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE