What is a Circadian Rhythm and How does it Work?

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3. What is a Circadian Rhythm and How does it Work?

Circadian rhythm affects your sleep pattern and the functioning of your body. It affects your hormones, body temperature, and eating habits. When the circadian rhythm gets out of sync, it causes several health problems including diabetes, obesity, and depression.

In this article, we will describe what is a circadian rhythm and how it works.

What is a Circadian Rhythm?

A circadian rhythm or circadian cycle, is a natural internal clock that regulates the sleep and wake cycle. It repeats roughly every 24 hours.

Different systems of the body follow circadian rhythms that are synchronized with a master clock in the brain. This master clock is directly influenced by environmental cues, especially light, which is why circadian rhythms are tied to the cycle of day and night.

It has been found that circadian rhythm can also be influenced by other factors such as ambient temperature, meal times, stress and exercise.

Let us look at how a circadian clock affects the human body at different times.

Effects of Circadian Clock times on Human Body

How does a Circadian Rhythm work?

The master clock is found in the suprachiasmatic nucleus or S.C.N, which is in a part of the brain called the hypothalamus.

The suprachiasmatic nucleus (SCN) is responsible for regulating circadian rhythms in all organs. It receives direct inputs from a class of nerve cells in the retina that act as brightness detectors, which can reset the clock genes in the SCN on a daily basis. The SCN then transmits to the rest of the brain and body signals that bring all of the daily cycles in synchrony with the external day-night cycle.

When circadian rhythm is properly synchronized, it can promote consistent and restorative sleep. But when this circadian rhythm is not in sync, it can create problems in diverse aspects of physical and mental health, including sleep problems.

The suprachiasmatic nucleus has a direct neural connection to the pineal gland, which releases the hormone melatonin at night. When Pineal gland in brain is stimulated from darkness at night, it makes melatonin which is circulated in the blood. Melatonin helps in cleaning up free radical damage and oxidative stress in the body. Your exposure to sun light during the day can boost melatonin levels at night during sleep.