Changes in eccrine sweating on the glabrous skin of the palm and finger during isometric exercise

The goals of this study were to investigate changes in the sweating and cutaneous vascular responses on the palm and the volar aspect of the index finger during sustained static exercise of increasing intensity and to determine whether the former can be attributed to altered sweat gland activity.

Five male and five female subjects performed maximal voluntary handgrip contractions (MVC: right hand) for 60 s at 20, 35 and 50% MVC (ambient temperature 25 °C, relative humidity 50%).

The sweat rate and the number of activated sweat glands on the non-exercised hand showed intensity-dependent increases (P < 0.05). At 35 and 50% MVC, finger sweat secretion was significantly higher than on the palm, which was primarily associated with the number of activated sweat glands (P < 0.05). In addition, there was a marked simultaneous decrease in the cutaneous vascular conductance for the finger at 35 and 50% MVC (P < 0.05), but not for the palm.

Our results suggest that a difference exists between intensity-dependent increases of sudomotor responses within more than one glabrous skin site. Specifically, markedly greater sweating occurs on the volar finger than on the palmar surface during sustained static exercise. These differences in sweat rate mainly resulted from changes in the number of activated sweat glands. In addition, intra-segment variations in cutaneous blood flow on the glabrous hand are shown.