AJP - Regulatory, Integrative and Comparative Physiology, Vol 239, Issue 3 233-R240, Copyright © 1980 by American Physiological Society
Heat intolerance as a function of percent of body surface involved with miliaria rubra
K. B. Pandolf, T. B. Griffin, E. H. Munro and R. F. Goldman
Twenty-four heat-acclimatized male volunteers were wrapped as previously
described (Am. J. Physiol. 239 (Regulatory Integrative Comp. Physiol. 8):
R226-R232, 1980) but to produce miliaria rubra (heat rash) in specific
regions of the body. Three experimental rash groups were involved: 1) the
torso (17% total skin surface rashed, n = 6), 2) torso and arms (38%, n =
8), or 3) legs (41%, n = 6), while four subjects served as controls. All
subjects were reexposed to walking in the heat on the 7th day after
unwrapping, and again 14, 21, and 28 days after unwrapping. When compared
to responses for the last heat acclimatization day, tolerance time and
sweat rate were lower and mean body temperature and delta heat storage
significantly higher for experimental rash subjects contrasted to the
controls for up to 21 days; however, no significant differences between the
three rashed groups were found. The critical amount of surface area for
heat intolerance from heat rash appears to be related to the specific
region of the body and associated sweating responses; smaller rashed areas
of the trunk, because they have greater potential for abundant sweating,
may produce similar responses to heat stress as larger rashed areas of the
limbs. Heat intolerance due to rash was not resolved until after 21 days.
