Health & Fitness

What Is a Circadian Rhythm?

A circadian rhythm is the body's roughly 24-hour internal cycle that regulates sleep and wakefulness, hormone release, body temperature, and other functions. It is synchronized mainly by light exposure. Disruptions, such as jet lag or shift work, occur when the internal clock is out of step with the local time.

Jet Lag

Crossing several time zones shifts local time faster than the body clock can adjust, which typically takes several days depending on the direction and number of zones.

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🔗 Related Terms

Sleep Cycle REM Sleep Time Zone

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Last updated: September 27, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.