The influence of bicycle exercise, with or without hand immersion in cold water, on forearm sweating in young and middle-aged women.

Forearm sweat production rate (SPR) and external auditory meatal temperature (TEAM) were examined in five young and five middle-aged women in response to intermittent exercise, on three separate occasions. The first experiment was a control study, while in the second study the left hand was immersed in cold water at the onset of sweating during each exercise bout, and in the third study this immersion was accompanied by venous occlusion of the upper left arm. TEAM increased by 0.5 degrees C during exercise with no significant differences between the groups on any occasion. The young women displayed a greater peak SPR during exercise in the control than the middle-aged women (52.5 +/- 23.9 vs. 16.7 +/- 6.5 mg cm2 h-1, P less than 0.001). With hand immersion, peak SPR was depressed to 14.0 +/- 4.6 mg cm2 h-1 (P less than 0.001) in the young women and to 13.1 +/- 4.5 mg cm2 h-1 in the middle-aged (P less than 0.05). With hand immersion and venous occlusion the peak SPR in young women increased (43.0 +/- 9.2 mg cm2 h-1). In the older women SPR was 14.9 +/- 6.1 mg cm2 h-1, which was not different from either control or cold-immersed values. Thus, forearm SPR during low-intensity intermittent exercise is greater in young compared with middle-aged women, despite similar changes in TEAM. The response to hand immersion in cold water was more marked in the young subjects.