Limb vs trunk sweat gland recruitment patterns during exercise in humans

The purpose of this study was to examine the sweat gland recruitment patter n, on multiple trunk and limb sites, during exercise. Nineteen male volunte ers performed 30 min of exercise on a cycle ergometer at approx. 25, 50 and 75% of their maximal oxygen uptake. The number of active sweat glands (per cm(2)) was determined immediately following each exercise bout at the foll owing six sites: left triceps, chest, back, forearm, thigh and calf. The da ta showed that increases-in rectal temperature during exercise resulted in a linear increase in the absolute number of active sweat glands recruited a t all six sites (r = 0.60-0.80). However, on a percentage basis, the limb s ites increased proportionally more (300-600% increase) than the trunk sites (100-200% increase) with increases in rectal temperature. These data sugge st that the absolute number of sweat glands recruited, on both the trunk an d the limbs, increases in a linear manner with increases in rectal temperat ure during exercise. However, on a proportional basis, sweat gland recruitm ent on the limbs is greater than that found on the trunk during progressive exercise. (C) 2000 Elsevier Science Ltd. All rights reserved.