Journal of Applied Physiology, Vol 50, Issue 4 741-746, Copyright © 1981 by American Physiological Society
Effect of acclimatization to heat on the regulation of sweating during moderate and severe exercise
C. T. Davies
Sweat regulation in two male subjects, one an athlete in training, was
examined over a range of exercise intensities and environmental
temperatures. The results after artificial heat acclimatization in the
nonathlete showed that sweating rate over 1 h of maximal exercise increased
to the same level as the athlete, but his evaporative sweat loss remained
significantly (15%) lower. Rectal temperature (Tre) was reduced for a given
oxygen intake (VO2) and relative work load (%VO2 max), but the difference
in Tre/%VO2 max between the subjects was not significant. At different mean
skin temperatures (Tsk), relative sweat rate (%msw, max), for a given Tre
was unaffected and the relationship of %mSW, max with Tre was the same in
both subjects. Lowering the relative work load (and thus Tre) displaced the
Tre/%msw, max relationship to the right, and regression lines for different
%VO2 max were parallel. The multiple regression equation %msw, max = -1,531
+/- 36.67 Tre (degrees C) + 6.08 Tsk (degrees C) (r = +0.92), related the
parameters and was independent of the subject's fitness and state of
acclimatization providing %msw, max was expressed in terms of the
appropriate msw, max at the time of measurement.
