Ultradian rhythm
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An ultradian rhythm is a biological rhythm that repeats more than once within a 24-hour day. Ultradian processes range from rapid cellular or neural oscillations to cycles lasting several hours.
Examples include stages of sleep, pulsatile hormone secretion, heart and breathing rhythms, patterns of feeding and alertness, the nasal cycle, and recurring changes in brain activity. Different ultradian rhythms are generated by different physiological mechanisms.
The approximately 90-minute alternation of non-REM and REM sleep is one widely discussed example, although cycle length varies through the night and among individuals. Hormones may also be released in pulses whose timing is necessary for normal signalling.
Ultradian rhythms can interact with circadian rhythms, sleep pressure, meals, activity, stress, and environmental conditions. Their analysis requires measurements frequent enough to distinguish genuine repeated oscillations from noise or slower trends.
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- Source / publisher: Wikipedia
- URL type: WWW
- Credits: Wikipedia
- URL: https://en.wikipedia.org/wiki/Ultradian_rhythm