Wilderness Environ Med. 2012 Jul 3. [Epub ahead of print]
Fifty-Three Hours of Total Sleep Deprivation Has No Effect on Rewarming From Cold Air Exposure.
Source
Exercise and Environmental Physiology Laboratory, Kent State University, Kent, OH; Department of Health, Physical Education and Sport Science, Kennesaw State University, Kennesaw, GA.
Abstract
OBJECTIVE.-:
Sleep deprivation and cold air exposure are both experienced in occupational and military settings but the combined effects of these 2 stressors is unknown. The purpose of this study was to determine the effects of 53 hours of total sleep deprivation on thermoregulation during the rewarming phase (25°C air) after acute cold air exposure (10°C air).
METHODS.-:
Eight young men underwent 2 trials in which they either received 7 hours of sleep at night or were totally sleep deprived. On 3 consecutive mornings, the subjects underwent 2 hours of cold air exposure followed by 2 hours of rewarming. Rectal temperature, mean skin temperature, oxygen consumption, and thermal sensation were measured.
RESULTS.-:
Rewarming from acute cold air exposure caused a decline in rectal temperature (∼0.5°C) each day but this was not different between subjects who were totally sleep deprived and subjects who received 7 hours of sleep at night. During this same period, mean skin temperature increased (from ∼22°C to 27°C), oxygen consumption decreased (from ∼7 to 4 mL·kg(-1)·min(-1)), and the participants felt warmer.
CONCLUSIONS.-:
Under the conditions of the present study, sleep-deprived persons are not at a greater risk for a decline in rectal temperature (ie, a hypothermic afterdrop) during rewarming from cold air.
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