Publication Date |
2009 |
Personal Author |
Eastman, C. I. |
Page Count |
37 |
Abstract |
Humans, like most of the plants and animals on the planet, have an internal circadian clock which produces daily (circadian) rhythms in almost all functions and variables such as body temperature, cognitive and physical performance, the secretion of hormones and neurotransmitters, etc. Our circadian clocks are synchronized to the 24 hour day primarily by the light and dark to which we are exposed, to the 24 hour light-dark cycle. As diurnal animals we are programmed by our circadian clocks to feel sleepy and to sleep at night, and to be awake and alert during the day. Body temperature, alertness and performance reach a low point around 4 to 6 am. This creates a problem for night shift workers who feel sleepy and are most prone to accidents at work, especially near the end of the night shift. This low point produced by the circadian clock persists even if the worker obtains enough sleep during the day. Furthermore, since we are programmed to be alert during the day, night shift workers often have shortened and disrupted sleep when they go home to sleep during the daytime after the night shift. This results in cumulative partial sleep deprivation which exacerbates the natural circadian dip in alertness during the night shift. |
Keywords |
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Source Agency |
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NTIS Subject Category |
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Corporate Authors |
Rush Univ., Chicago, IL. Medical Center.; National Inst. for Occupational Safety and Health, Washington, DC. |
Supplemental Notes |
See also PB2015-102118. Sponsored by National Inst. for Occupational Safety and Health, Washington, DC. |
Document Type |
Technical Report |
NTIS Issue Number |
201507 |
Contract Number |
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