Circadian Rhythm: What It Is, How It Works, And More | Restful Sleep
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Misbah Wasi

Functional Nutrition Specialist, Scientific & Regulatory Advisor for Health Supplements

Misbah Wasi is a seasoned professional in the field of Nutrition Science and Food Regulation for over 15 years. Currently, she is lendin her expertise in the area of Health Supplements and Nutraceuticals and is an active member of the Standards Review Group (SRG) - Nutraceuticals FSSAI Ms. Wasi is a post-graduate in Food and Nutrition. Certified Lead Food Safety Management Systems Auditor (FSMS, FSSC 22000) and a certified FoSTaC traine for Health Supplements and Nutraceuticals. She is also a Subject Matter Expert for ‘Food Regulations in India’ for IFLR (International Food Laws and Regulations) course at Michigan State University.

Circadian Rhythm: What It Is, How It Works, And More

You already know that poor sleeping habits can adversely affect your body. But sleeping at odd hours also has a severe impact on our health. Our body is scheduled to work in the day and sleep in the night. Disrupting this pattern results in various health problems and sleeping disorders.

Circadian Rhythm

Circadian rhythm is the 24-hour internal clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment. Our physiology and behaviour are shaped by the Earth’s rotation around its axis. The regulation of sleep is processed by the homeostatic physiology of the circadian rhythm, the sleep/wake cycle. This biological circadian system has evolved to help humans adapt to changes in our environment and anticipate changes in radiation, temperature, and food availability.

How does circadian rhythm work?

The term circadian comes from the Latin phrase “circa diem,” which means “around a day.” These circadian rhythms work by making sure that the body’s processes are optimized at various stages during a 24-hour period. Circadian rhythm is present in all kinds of organisms. The circadian rhythm is managed by the central clock “master clock,” called the suprachiasmatic nucleus (SCN) of the hypothalamus. It is responsible for regulating stress, reproduction, and growth hormones and indirectly impacts sleep hormones.
During the day, light Exposure causes the internal clock to send signals that generate alertness and help keep us awake and active. As night falls, the internal clock initiates the production of melatonin, a hormone that promotes sleep, and then keeps transmitting signals that help us stay asleep through the night. In this way, circadian rhythms align sleep and wakefulness with day and night to create a stable cycle of restorative rest that enables increased daytime activity.

What can Obstruct Circadian Rhythm?

The disturbance in the circadian rhythm can take place from short- or long-term factors. Some of the factors are mentioned below.
  • Light: Irregular Exposure to light can disrupt circadian rhythm.
  • Irregular sleep schedule: Sleeping for fewer hours or, at times, disturbs the sleep-wake cycle.
  • Jet lag: Travelling between different time zones may hamper the sleep cycle. The day-night cycle of the new location generally results in fatigue and sleepiness.
  • Shift Workers: People working on a shift basis require to work through the night and sleep during the day.

How to improve circadian rhythm?

Various tips can help you to get back to a normal circadian rhythm. This is a gradual process but will improve not only your sleeping problems but will enhance your overall health.
  • Light Exposure during the day: Exposure to sunlight helps build the strongest circadian rhythm.
  • Create an effective sleeping pattern: Everyone has a varied sleep schedule. Try to go to bed at the same time every night. This will allow our central body clock to balance the circadian rhythm and prepare our body to experience deep sleep every night.
  • Avoid Caffeine: Caffeine has varied effects from person to person. It is recommended to avoid caffeine at least 6 hours before sleeping. Caffeine might help you to wake up in the morning, but it has terrible effects on the sleep cycle.
  • Reduce screen time before bedtime: Long Exposure to blue light at night lowers the quality and duration of sleep. It is best to avoid using gadgets at night rather than indulge yourself in some positive thoughts or planning the next day.
  • Workout during the day: Exercising every day affects your mind and soul positively. Some activities in the day will help improve the duration of sleep.
  • Do not nap during the day: You should not rest for more than 45 minutes in the afternoon. Sleeping for more than 2 hours daily will lower your sleep quality at night and disrupt the sleep-wake cycle.
Circadian rhythm is an essential physiological process that regulates the sleep-wake cycle and other functions of the body. By improving your circadian rhythm, you can promote better sleep, improve overall health, and enhance productivity and well-being.


  2. Reddy S, Reddy V, Sharma S. Physiology, Circadian Rhythm. [Updated 2022 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
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