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  • The word "circadian" comes from Latin "circa diem" and means "about one day." Circadian clocks run on a cycle that is approximately 24 hours long
  • Circadian clocks still function with constant light and temperature or constant dark. Even in places like Antarctica, where it is light half the year and dark half the year, circadian clocks regulate bodies as they would anywhere else in the world. This just goes to show that it is an innate system, and outside factors like light and temperature do not influence the function of that system
  • Chronotherapy is a new area of medicine that uses information about body clocks to treat illness and optimize health (more info)
  • Because of circadian clocks, heart attacks are more likely in the morning and asthma attacks are more likely at night.
  • It takes people 7 days to adjust to a new sleep pattern, but only one day to return to old sleep patterns. Circadian clocks never adjust completely to the environment. They are permanently set to a certain time pattern.
  • In order to keep body rhythms in tune, experts recommend getting up at about the same time every day, regardless of the amount of sleep you've gotten (more info)
  • Many industries that employ workers 24/7 have begun requesting advice from scientists about work schedules in order to increase productivity (more info)
  • Pharmaceutical companies are investigating drugs that may affect circadian rhythms in humans, since many cardiovascular, sleep, neurological, and endocrine disorders are caused by abnormal circadian function (more info)
  • Knowledge of plant circadian rhythms helps the agricultural industry manipulate growing seasons (more info)
  • A recent study on zebrafish found that mother zebrafish set the circadian clocks of their offspring before birth (more info)

University of Arizona
Biology 181H Group 03
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Revised: 13 Nov 2004
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