Phase-Shifting Effects of Light and Activity on the Human Circadian Clock
Final rept. 1 Nov 1997-31 Oct 1999
CHICAGO UNIV IL DEPT OF MEDICINE
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Basic human research experiments conducted at the University of Chicago examined jet lag and sleep loss, conditions that are highly relevant to Air Force operations. First, a series of studies examined the photic and nonphotic means by which the timing of the human circadian system can be changed. These protocols were typically of 3-4 days duration involving collection of 24-hour profiles of neuroendocrine and other physiological parameters under constant routine conditions to determine the phase-shifting effects of exercise and darksleep on hormonal markers of circadian phase. The results indicate that periods of either exercise and darksleep can change circadian phase, which has potential practical benefits for conditions of jet lag and night work. Second, the effects of partial sleep loss on metabolic, endocrine, cognitive, cardiovascular, and immune function, neurobehavioral performance, and subjective sleepiness and mood have been examined in separate studies not funded by this grant but nevertheless highly relevant to Air Force operations. These protocols involved 16-day studies with one-week periods of sleep restriction to 4 hoursnight and sleep extension to 12 hoursnight. The results indicate that sleep loss has a profound deleterious impact on human health and performance that can be improved by sleep extension.
- Anatomy and Physiology