About 386,000 results
Open links in new tab
  1. Circadian rhythm - Wikipedia

    A circadian rhythm (/ sərˈkeɪdiən /), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism …

  2. Circadian Rhythm: What It Is, How It Works & What Affects It

    Your circadian rhythm is the pattern your body follows based on a 24-hour day — it’s the name given to your body’s internal clock. This rhythm tells your body when to sleep and when to …

  3. What Is Circadian Rhythm? - Sleep Foundation

    Jul 23, 2025 · Circadian rhythms affect many bodily processes, your mental state, and your behavior. Perhaps the most well-known circadian rhythm is the sleep-wake cycle, which …

  4. CIRCADIAN Definition & Meaning - Merriam-Webster

    Most often, it's seen and heard in the term circadian rhythm, which refers to the inherent cycle of about 24 hours that appears to control various biological processes, such as sleep, …

  5. Circadian Rhythms - National Institute of General Medical Sciences

    May 20, 2025 · Most living things have circadian rhythms, including animals, plants, and microorganisms. In humans, nearly every tissue and organ has its own circadian rhythm, and …

  6. Circadian Rhythm: What It Is, How it Works, and More - Healthline

    Jan 22, 2025 · Your circadian rhythm is your body’s internal clock. Light, sleep patterns, hormones, meals, and temperature can all influence your circadian rhythm, which in turn can …

  7. Circadian rhythm | Definition, Examples, & Facts | Britannica

    6 days ago · circadian rhythm, the cyclical 24-hour period of human biological activity. Within the circadian (24-hour) cycle, a person usually sleeps approximately 8 hours and is awake 16. …

  8. Circadian Rhythms – Introduction to Neuroscience

    Activity in the suprachiasmatic nucleus inhibits the pineal gland and production of melatonin. A 24-hour cycle is called a circadian rhythm Circadian rhythms are entrainable to zeitgebers, or …

  9. Sleep & Circadian Basics - Sleephealth.org

    Learn sleep & circadian basics and get familiar with the master clock that controls sleep and circadian rhythms throughout the day.

  10. The Biological Clock: How Circadian Rhythms Affect You

    Apr 21, 2025 · Circadian rhythms have been found in nearly every form of life, from single-celled cyanobacteria to humans. They likely evolved billions of years ago in response to the planet’s …