Confused and have questions? We’ve got answers. With Chegg Study, you can get step-by-step solutions to your questions from an expert in the field. If you rather get 1:1 study help, try 30 minutes of free online tutoring with Chegg Tutors.

Infradian rhythm

From Biology-Online Dictionary
Jump to: navigation, search


noun, plural: infradian rhythms

A biological rhythm that is repeated longer than a 24-hour circadian day and therefore recurs over a longer period than a circadian rhythm


Biological rhythms pertain to the synchronized cyclic pattern demonstrated by an organism as its response to a particular stimulus. Biological clock that synchronizes with biological rhythm may be endogenous or exogenous. An endogenous type is one in which the internal biological clock is the one that controls it. An exogenous type is one that which involves an external cue (i.e. zeitgeber). There are the different types of biological rhythms: circadian rhythms, diurnal rhythms, ultradian rhythms, and infradian rhythms.1

An infradian rhythm has a longer period than a circadian rhythm. The cycle is repeated more than the 24-hour circadian day. This is in contrast to the ultradian rhythm wherein it recurs in periods shorter than a day but longer than an hour.2 In infradian rhythm, the frequency is less than one cycle in 28 hours.3

Examples of an infradian rhythm include menstrual cycle, breeding, seasonal rhythms, etc.

See also:

1 Hedge, A. (2013). Biological Rhythms. Retrieved from [[1]]
2 "Ultradian, adj." Oxford English Dictionary. Retrieved from [[2]].
3 Brown, F. M. & Graeber, R. C. (1982). The Rhythmic Aspects of Behavior. Hillsdale, NJ: Lawrence Erlbaum Associates. p.462.