Abstract
Effects of sleep deprivation and season on thermoregulation during 60 min. of leg-bathing (water temperature of 42°C, air temperature of 30°C, and relative humidity of 70%) were studied in eight men who completed all 4 experiments for normal sleep and sleep deprivation in summer and winter. Rectal temperature (Tre), skin temperature, total body sweating rate (Msw-t), local sweating rate on the back (Msw-back) and forearm (Msw-forearm), and skin blood flow on the back (SBFback) and forearm (SBFforearm) were measured. The changes in Tre (ΔTre) were smaller (P<0.05) for sleep deprivation than for normal sleep regardless of the season. This decrease in ΔTre was significant only in summer (P<0.05). Mean skin temperature (T(mean of)sk) was higher (P<0.05) for sleep deprivation than for normal sleep regardless of the season. Msw-t was smaller (P<0.05) for sleep deprivation than for normal sleep regardless of season, although Msw-back and Msw-forearm were similar. SBFback and SBFforearm tended to be higher for sleep deprivation than normal sleep. The sensitivity of SBF to Tre was higher (P<0.05) for sleep deprivation than for normal sleep. These data indicate that seasonal differences in thermoregulation were small because of morning time. Sleep deprivation increased dry heat loss and restrained Tre rise, in spite of decreased sweating rate.
