What is the Circadian Rhythm

Our body is like a clock. Each breath, the ticking hands of that clock and our soul, its battery. Our bodies have a rhythm. They have an internal routine set, that we knowingly or unknowingly follow. Waking up at a particular time, or having difficulty falling asleep at night is all linked to the same body clock, at the end of the day. This particular body clock is known as the circadian rhythm.  

The word ‘Circadian’ is derived from the Latin phrase “Circa Diem” meaning ‘around the day’. The Circadian rhythm is thus a 24-hour cycle, running to carry out essential processes and functions. It works as a part of the body’s internal clock. Different systems of the body are synchronised with a master clock in the brain, following the Circadian Rhythm for optimal functioning. 

One of the most important kinds of Circadian Rhythms is the sleep-wake cycle. Since the rhythm is influenced by environmental cues such as light reception, when properly adjusted, the Circadian Rhythm promotes consistent and restorative sleep. Similarly, if it is thrown off, it can lead to sleeping problems such as insomnia.  

How It Works 

The Circadian Rhythm plays an essential role in maintaining the development and functioning of practically all systems of the body. It exists in every kind of organism. For example, it prevents nocturnal animals from leaving their shelters during the daytime, eliminating them from being exposed to more predators, and helps flowers open and close at the required time. In humans, the Circadian Rhythm is in charge of various mental and physical functioning. 

The digestive systems of us humans produce certain proteins to match what the typical meal times are. Similarly, our endocrine system regulates hormone secretions to match the required amounts of energy expenditure. It also influences our mental health. A disturbance to it can cause us to be more susceptible to illnesses such as depression or bipolar disorder, along with neurodegenerative diseases like dementia. 

To top it all off, the Circadian Rhythm has been found to influence our immune systems and DNA repair. Research indicates that Circadian cycles can influence the effects of anti-cancer drugs, harnessing the biological clocks of the body to kill the cancer cells. 

The Circadian Rhythm gets adjusted, based on work hours, stress and anxiety levels, amounts of physical activities and varying lifestyle choices. Age is also another influencing factor. Thus, infants, adolescents and adults, all experience it differently. But what can not be contested is how important it is to strike a good balance in the rhythm and maintain healthy lifestyles. 

The Science Behind It

Throughout the body, the Circadian Rhythm is connected to a master clock in the brain. It is sometimes referred to as the Circadian pacemaker. Found in the Suprachiasmatic Nucleus (SCN), a part of the hypothalamus, its clock genes send signals throughout the body to regulate activity. 

The SCN is extremely sensitive to light which serves as a crucial cue, influencing the signals being sent to coordinate internal clocks in the body. Other cues such as social activity, exercise and temperature also affect the master clock. However, light is among the most powerful cues in terms of influence. 

The brain receives signals based on our current environment. Certain hormones are thus activated. Our body temperature alters, metabolism regulates and we are either made alert or drawn to sleep. 

Difference between Biological Clocks and Circadian Rhythm 

Several components and cues make up our Circadian Rhythm. Similarly, our body has several biological clocks. Our biological clocks help in regulating the timing of mental and physical processes, including our Circadian Rhythm. So to be exact, our Circadian Rhythm is just one of the four biological clocks in the body.

If we take this up using an example, plants adjusting to the changing of seasons is a work of their body clocks. However, seasons, in terms of timings, are different from a 24-hour cycle of the Circadian Rhythm. So for a flower of the same plant to open up or close, depending on the timings of the day, will be a process that the Circadian Rhythm is responsible for. 

The connection between the Circadian Rhythm and Sleep

As has already been discussed, the sleep-wake cycle is one of the most well-known examples of the Circadian Rhythm. During the day, the exposure to an abundance of light causes the master clock to send signals of alertness. This cue of light keeps us awake and active. As we proceed into the night, and the light dims, the hormone melatonin is secreted. It promotes sleep. The master clock continues to transmit signals of melatonin production for us to stay asleep throughout the night. 

Thus, the Circadian Rhythm aligns our sleeping schedule with day and night. A stable cycle is therefore created to ensure restorative sleep at night and increased productivity during the daytime. 

However, when it is thrown off, the body stops functioning at an optimal level. A disturbed sleep-wake cycle can lead to serious sleeping disorders. Without proper signals from the master clock, the person can face difficulty falling asleep at night. Problems in terms of how long a person sleeps, or how much they wake up throughout the night also get affected. Low quality and fragmented sleep are common symptoms of a disturbed sleep-wake Circadian Rhythm. The risk of insomnia and daytime sleepiness also increases.

Studies have also shown that such disruptions can be a potential contributor to obstructive sleep apnea (OSA). Common symptoms include poor sleep quality, marked by lapses in breathing, decreasing the body’s oxygen levels.  

Since the quality and quantity of sleep matter for the overall health and functioning of the body, such consequences need to be avoided at all costs. 

How can a Healthy Rhythm be Maintained 

It would be wrong to say that we can completely control our Circadian Rhythm. However, there are some healthy tips that we can try, which will better entrain and enforce a more regular cycle. 

– Sun Exposure

Since light is one of the strongest cues, exposure to natural light will help reinforce a better and more natural cycle. 

Daily exercise

When a person indulges in physical activity during the day, it can make them more tired at night. This can help the internal clock make you fall asleep at night without much hassle. 

– Consistent sleep schedule

It is easier to maintain a cycle if the routine at which one goes to bed and wakes up is roughly the same. Varying the bedtime or the time one wakes up can hinder the body’s ability to adjust to a relatively stable cycle.

Limit afternoon naps

Keeping naps short and early during the afternoon can help not delay your routine’s bedtime. However, if one indulges in long and delayed naps, it can push back the person’s bedtime. This will throw off their sleep schedule, as they might not feel that sleepy at night. 

Avoid Caffeine

Caffeine is a kind of a stimulant that can keep a person up and awake, no matter what the circumstance. This can throw off the natural balance between feeling alert and sleepy.

Limit screen time before bed

Artificial light exposure at night interferes with the body interpreting light cues and preparing the body to either stay alert or feel sleepy. Thus, it is advisable to dim the lights and not use electronic devices right before bed.

The above-mentioned tips help improve the quality of our sleep. Everyone is different and is differently affected by varying cues. However, these have been observed to affect the multitudes, helping them maintain a constant sleep-wake rhythm. 


Maintaining our Circadian Rhythm is essential to good health. This is because disruption to our circadian rhythm and sleep schedules can have several short-term and long-term effects. Our organs, cardiovascular systems, skin, gastrointestinal systems and metabolism can all be affected by poor quality sleep and a disturbed Rhythm. Additionally, a person also becomes more susceptible to diabetes, mental health conditions and obesity. Memory loss issues, delayed wound healing and lack of energy are also common consequences to it. There can also be changes to the hormonal balance, affecting fertility, shifts in body temperatures and problems regarding digestion. 

However, sometimes when such alterations in our Circadian Rhythm and overall wellness of the body take place, it can be an indication of a much bigger problem. Circadian Rhythm Sleep Disorder, resulting in an advanced sleep phase or delayed sleep phase is a possible problem. 

Treating these conditions includes a variety of approaches. Light therapy or taking medications and supplements are possible courses of action. Taking melatonin doses, setting up a more regular routine or talking to a medical professional is also helpful. 

So if you feel that you or a loved one may be suffering from an irregular sleep-wake cycle and an imbalance in their Circadian Rhythm, you can always reach out to us at Venthrapy to discuss further actions and preventive measures. 

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