Exercise, Circadian Ryhthms, and Hormones

It is important for human health and efficiency to maintain physiological and biochemical processes within narrow bands in spite of external influences. This homeostasis is achieved by means of negative feedback control loops, and superimposed on the “constancy” produced by it, there are rhythmic changes. The main rhythms can have a period—the length of time that elapses until the cycle is repeated—of a day, week, month, or year. Ultradian rhythms refer to cycles with a period of <20 h and that recur within a single day. With regard to those rhythms with a period of a day, which are therefore known as circadian rhythms, there is now good evidence that an internal “body clock” contributes to their control. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.