SLEEP-DEPRIVATION ALTERS BODY-TEMPERATURE DYNAMICS TO MILD COOLING AND HEATING NOT SWEATING THRESHOLD IN WOMEN

Sleep deprivation alters thermoregulatory responses. We used control o f skin temperature to produce mild thermal challenge, both cool (32 de grees C) and warm (38 degrees C), and recorded esophageal and rectal t emperatures, sweat rate and forearm blood flow in six healthy young wo men at rest. We discovered that after one night of sleep deprivation ( 1) both mean esophageal and rectal temperatures were reduced, (2) the mean threshold for sweating was not altered, and (3) there was no dire ct indication that skin blood flow was set at different levels with sk in temperature neutral or cool. Peripheral vasodilation was attenuated when skin temperature was held at 38 degrees C. Following this period of mild hyperthermia, esophageal and rectal temperatures decreased mu ch more rapidly in sleep-deprived subjects when skin temperature was c ooled and held constant at 32 degrees C. We conclude that sleep-depriv ed women lose heat rapidly in response to a mild cooling stimulus. Sle ep-deprived humans may be more vulnerable to heat loss with reduced ab ility to warm even at temperatures thought to be associated with therm al comfort.