Circadian Rhythms

A circadian rhythm, or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism and responds to the environment. These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in animals, plants, fungi and cyanobacteria. The term circadian comes from the Latin circa, meaning "approximately", and dies, meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms; diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. Although circadian rhythms are endogenous, they are adjusted to the local environment by external cues called zeitgebers, which include light, temperature and redox cycles. In clinical settings, an abnormal circadian rhythm in humans is known as a circadian rhythm sleep disorder.

Read more in the app

Mimicking an enigmatic property of circadian rhythms through an artificial chemical clock

What Happens if Your Body Clock Is Out of Whack? Disrupted Circadian Rhythms Linked to Cancer

What happens if your circadian rhythms are out of whack?

What Drives the Circadian Rhythms: Unlocking Complex Workings of the Biological Clock

Links between circadian rhythms, metabolism and addiction

We Just Got Closer to Finding a Link Between Alzheimer's And Circadian Rhythms

Circadian Rhythms Control Immune Cells That Clear Away Alzheimer’s Disease Protein

The Obesity Paradox and Circadian Rhythms in Heart Failure

Tracking circadian rhythms from your smartwatch

Clock proteins regulate spatiotemporal organization of clock genes to control circadian rhythms

How Your Circadian Rhythms Control Your Every Waking — and Sleeping — Moment

Technology Really Is Changing Human Circadian Rhythms, Scientists Say

Daily Rhythms May Impact Our Ability to Fight Disease – Immune System Killer Cells Controlled by Circadian Rhythms