AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 1 72-R77, Copyright © 1984 by American Physiological Society
Effects of sleep deprivation on thermoregulation during exercise
M. N. Sawka, R. R. Gonzalez and K. B. Pandolf
Five fit men completed a practice, control, and sleep deprivation exercise
test. Two nights of normal sleep preceded the control test, and 33 h of
wakefulness preceded the sleep deprivation test. These tests consisted of
20 min of rest followed by 40 min of cycle-ergometer exercise (50% of peak
O2 uptake, VO2) in a temperate (ambient temperature, 28 degrees C; relative
humidity, 30%)-environment. Esophageal temperature (Tes), local sweat rate
(mds), and chest thermal conductance (kch) were continuously measured.
During exercise a 0.7 and 0.5 degrees C rise in Tes was found for the sleep
deprivation and control tests, respectively. This increase in Tes values
from rest to the end of exercise was greater (P = 0.08) for the sleep
deprivation than control test. Total body sweat rate, calculated from
Potter balance measurements, was 27% less (P less than 0.01) for the sleep
deprivation than the control test. Both mds and kch values were lower (P
less than 0.05) during the final 20 min of exercise for the sleep
deprivation than control test. Final exercise mds values were 19% lower (P
less than 0.05) for the sleep deprivation than control test. An
asynchronous rather than a normal synchronous mds pattern was frequently
observed during the sleep deprivation test. During the sleep deprivation
test, the mds sensitivity (delta mds X delta Tes-1) was 38% lower (P less
than 0.01) and kch sensitivity (delta kch X delta Tes-1) was 42% lower (P
less than 0.05) than during the control test. These data indicate that
sleep deprivation decreases evaporative and dry heat loss during
moderate-intensity exercise.
