The Oxford Biblical Studies Online and Oxford Islamic Studies Online have retired. Content you previously purchased on Oxford Biblical Studies Online or Oxford Islamic Studies Online has now moved to Oxford Reference, Oxford Handbooks Online, Oxford Scholarship Online, or What Everyone Needs to Know®. For information on how to continue to view articles visit the subscriber services page.

Related Content

More Like This

Show all results sharing this subject:

  • Medicine and health


Show Summary Details


biological rhythm

Quick Reference

Any periodic, more-or-less regular fluctuation or cycle in a biological system or process that is not wholly under the control of environmental cues but is controlled centrally by a biological clock. It may be an ultradian rhythm such as a circannual rhythm or a menstrual cycle; a circadian rhythm such as the sleep-wake cycle; or an infradian rhythm such as an alpha wave, basic rest-activity cycle, beta wave, delta wave, gamma wave, sensorimotor rhythm, or theta wave. See also chronobiology, pacemaker neuron, suprachiasmatic nucleus, Zeitgeber. Compare biorhythm.

Reference entries