Body Clock |How It Works | circadian rhythm definition

Body Clock |How It Works | circadian rhythm definition

Circadian Clock

What is your body clock called?

The body clock is also known as Circadian clock. It is a natural internal clock that keeps track of time. The word “Circadian” is made up of two words

“circa+Diem”,

which means “around a day”.

For humans, it is for about 24.5 hours. But that doesn’t mean your body clock can add half an hour extra to your day. It means that if you are kept in total darkness, your body will still continue working in a 24-hour-long day fashion, provided that you aren’t too scared to function in the dark.

Individual cells will still show timely changes in gene expression to keep track of time. But without any cues, you will drift every day by half an hour. I wouldn’t try using this excuse on your boss though.

Your body has machinery in place to track time, but it happens at the speed of a mechanical clock. It is a little slow. Therefore, you need an actual clock, to adjust your physiology according to the day and night cycle.

why do you need an internal clock at all, you might wonder?

The answer is to predict. Having a built-in clock prevents you from being completely dependent on the environment. It gives you the control to function independently without being passive towards environmental changes.

You are able to predict and not just assume it’s nighttime when a room is dark.

biological clock sleep

A disturbed body clock can directly affect your sleep cycle. You might end up feeling sleep deprived which can have harmful effects over a long period of time.

Now, let’s dive into functions Of Body Clock.

Where is your body clock?

It was known for a long time that your daily rhythms are well regulated, but the exact location of this so-called “clock” was still unknown.

Circadian Rhythm Definition

During an experiment in the mid-20th century, scientists took out a small part of a hamster’s brain. This was called a “Suprachiasmatic nucleus” or, SCN. This resulted in the hamster losing its ability to maintain a body rhythm.

The rhythm production is a complex process. In simpler words, you can say that the Suprachiasmatic nucleus, situated right above the point of optic nerve fibers, has specialized clock genes. These genes are responsible for coding certain proteins.

If these proteins along with other regulatory proteins are present in amounts more than a threshold level, they switch off the clock genes. A kind of feedback mechanism. When the level of protein drops over time, genes are switched on again.

Thus, in turn, restarting the rhythmic cycle. This was all we knew until a recent study.

Jeffrey C. Hall, Michael Rosbash and Michael W. Young were awarded The Nobel Prize in Physiology or Medicine 2017 for their discoveries of molecular mechanisms controlling the circadian rhythm.

A fruit fly was the first multicellular organism the ‘body clock’ was discovered in. Yes, it’s true, those little guys hovering over your rotten banana.

Faults in the internal clocks of fruit flies were discovered by Seymour Benzer and his student Ronald Konopka in 1971. They traced back the mutation responsible for this fault in a particular gene. This gene was named PER. This was where our Nobel prize winners stepped in.

Circadian Rhythm In Humans

In 1984, Jeffrey Hall and Michael Rosbash started studying the PER gene. Their work, along with Michel Young’s, detailed multiple body clock gene levels rising and falling over a time period of 24 hours.

This study contributed significantly towards our understanding of a body clock’s functioning.

But the clock is not only genetically regulated. There’s more to it. It is also dependent on environmental factors, such as light and dark. Light acts as a reset signal. This keeps the organism in sync with the world outside.

Internal awakening might sound like a very real concept right now. But despite common perception, the clock is not only responsible for regulating your sleep cycle, but it also governs the functioning of other systems such as hunger, mental alertness, heart functioning, immunity, mood, and stress.

The mastermind behind everything is this clock. The one you were probably paying the least attention to. Even in the case of self-regulated organs like the heart. It plays a major role in controlling certain fluctuation such as blood sugar level. The heart relies on the clock for certain cues.

The genetic factor responsible for controlling the heart’s electrical signal and clock rhythm is the same. Such an understanding of the heart-clock connection has helped researchers in drug designing. It has been noticed that heart problems such as fatal arrhythmias are more likely to occur during morning hours and less likely in the evening.

This is the reason behind the consumption of blood pressure medicines in the evening time. This way they function in sync with your body’s circadian rhythms and gives effective results. So don’t miss out on your morning pills.

Similar to sleep cycle and heart functions, the clock regulates hunger and metabolism through hormones too. Even the immunity and inflammatory responses are regulated in a similar fashion.

It promotes the secretion of compounds involved in causing inflammation at night. This is why you usually get fevers during the evening. This happens because infections are fought better while the body is at rest. All of your energy can be utilized for this rather than other functions.

Similarly, the clock also reduces the activity of the stress hormone cortisol at night, assisting the immune response.

But when should we listen to our body clock and when to our wristwatches?

What happens if there’s a mismatch in our internal and external time?

Such a mismatch is most prominently seen in the case of jet lag and shift work. These phenomena go against regular patterns and can disturb physical and mental health.

Studies have shown a higher rate of traffic accidents and injuries when there’s a loss or excess of an hour’s sleep. Disrupting the clock can also increase the risk of myocardial infarction, diabetes, and cognitive decline.

So, time to scrap your outlook calendar and start listening to the one you have built-in.

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