Journal of Applied Physiology, Vol 47, Issue 6 1194-1200, Copyright © 1979 by American Physiological Society
Influence of air velocity and heat acclimation on human skin wettedness and sweating efficiency
V. Candas, J. P. Libert and J. J. Vogt
Before and after heat acclimation, four male resting subjects were exposed
to humid heat that caused levels of skin wettedness ranging from 50 to
100%. The physical experimental conditions were chosen so that the same
skin wettedness was attained with modification of only the ambient water
vapor pressure, at two wind speeds (0.6 and 0.9 m . s-1). The esophageal
temperature (Tes), mean skin temperature (Tsk), sweating rate (msw), and
dripping sweat rate (mdr) were recorded; the amounts of local drippage in
the same thermal conditions before and after acclimation were also
determined. The relationship between the evaporative efficiency of sweating
(eta sw) and the skin wettedness (w) is reported, as is the influence of
the subject's acclimation to humid heat on adjustments of skin wettedness.
The effects of the air velocity on the coefficient of evaporation and on
sweating efficiency are discussed. Beneficial increases in evaporation were
achievable by increasing skin wettedness only when there was a consistent
drippage, which differed from one body area to another and from one subject
to another. The relation of drift in body temperature to skin wettedness
changed with the acclimation of the subjects.
