- A circadian rhythm is a roughly 24-hour cycle in the physiological processes of living beings, including plants, animals, fungi and cyanobacteria.
- Circadian rhythms are endogenously generated, although they can be modulated by external cues such as sunlight and temperature.
- Circadian rhythms are important in determining the sleeping and feeding patterns of all animals, including human beings.
- the circadian rhythm most commonly determines the hours that a human being is asleep or awake during a day.
- There are clear patterns of brain wave activity, metabolic rate, blood pressure hormone production, cell regeneration and other biological activities linked to this daily cycle.
- Like a switch, light can turn off and turn on genes that control the molecular structure of biological clocks.
- Circadian rhythms are synchronized with the earth’s rotation by daily adjustments in the timing of suprachiasmatic nucleus (SCN), following the exposure to light which indicates the time of the day.