AJP - Regulatory, Integrative and Comparative Physiology, Vol 239, Issue 3 226-R232, Copyright © 1980 by American Physiological Society
Persistence of impaired heat tolerance from artificially induced miliaria rubra
K. B. Pandolf, T. B. Griffin, E. H. Munro and R. F. Goldman
Ten volunteers were heat acclimatized to 48.9 degrees C (Ta), 20% rh for 7
days to complete a 100-min walk on a level treadmill (1.56 m x s-1).
Subjects were then divided into experimental (n = 6) and control (n = 4)
groups. Miliaria rubra (heat rash) was then induced on the experimental
subjects by wrapping them for 3 days in polyethylene plastic. All six
developed marked miliaria with involvement of 40-70% of the total body
surface area. All subjects were reexposed to walking in the heat on the 7th
day after unwrapping, by which time rash was clinically indetectable, and
again 14 days after unwrapping. On the first test (day 7) only one of the
rashed group, and on the second test (day 14) only two could complete the
100-min walk; the control group finished without difficulty on both days.
Body heat storage for the rash group was 2.5 times that of the control
group on day 7 and 1.5 as great on day 14; measurements of mean body
temperature (Tb) on the rash group indicated a much greater heat stress
when compared to their own prerash-acclimatized values or those of the
control group. These data demonstrate the potential of "healed" miliaria in
the etiology of clinical heat illness.
