Body Clocks – Environmental and Biological Rhythms

by Kendra Van Wagner at http://psychology.about.com/od/statesofconsciousness/p/BodyClocks.htm

All species have a timing mechanism, or ‘clock,’ that controls periods of activity and inactivity. These clocks are known as circadian rhythms and refer the cycle of physiological and biological processes that fluctuate on a roughly 24-hour timetable. You’ve probably noticed these tendencies yourself, feeling more energetic and alert during peak periods of the day and more lethargic and run-down at other times of the day.While many people refer to circadian rhythms as a single process, there are actually a number of body clocks that oscillate throughout the day. For example, mental alertness tends to peak twice in a day at 9AM and 9PM, while physical strength tends to crest at 11AM and 7PM.

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