What is circadian rhythm?

First, we need to know about the biological clock. Biological clock or body clock refers to a mechanism that is inside our body and controls every activity of the body. Metabolism, sleep-wake pattern, hormone production, mood, etc. are all controlled by the biological clock. The main function of the biological clock is to ensure that every physiological task is completed at the right time.

Every organism, including humans, follows a biological clock. Each clock follows a different time pattern and is named accordingly. For example, the human biological clock operates within a 24-hour period, so it is called a circadian rhythm. Again, the flowering or growth of plants in different seasons follows another biological clock, which operates for about 1 year.

Since the circadian rhythm operates in a 24-hour period in accordance with the Earth’s rotation, it has a deep relationship with day and night. It controls our sleep and wake times. That’s why it’s also called the sleep-wake cycle. But not only that, the circadian rhythm also plays an important role in our body’s proper functioning.

How is it made?

Every organ in our body is connected to the brain. Circadian rhythm is also managed by the brain. There is a group of special nerve cells in the hypothalamus of our brain, which is called the Suprachiasmatic Nucleus (SCN). It is also called the master clock of the body. The nerve cells of the master clock are connected to the optic nerve of our eyes. Therefore, the master clock can send the necessary signals to the body to function in a way that senses light and darkness.

Let me explain the matter a little more. There is a special type of cell in the retina of our eyes, which can detect the brightness of the environment and thus understand when it is day and night. When light hits the eyes in the morning, these cells send this information to the master clock through the optic nerve. Then a signal is sent from the master clock in such a way that our body can get ready to wake up from sleep. Then our body temperature, heart rate and blood pressure increase slightly, which is part of waking up.

Then, when it gets dark after the sun sets, the master clock receives information about nightfall through the optic nerve and sends signals accordingly so that our body prepares for sleep. Then we fall asleep. This is how our sleep cycle is managed through the circadian rhythm.

You need to know about melatonin and cortisol hormones

The role of two hormones called melatonin and cortisol is very important in keeping the circadian rhythm dynamic. Melatonin is a hormone that controls our sleep cycle. It is produced in the pineal gland. When melatonin decreases during the day, we wake up from sleep.

In addition to melatonin, there is another hormone called cortisol, which is also known as the stress hormone. It helps us wake up in the morning. This hormone originates from the hypothalamic pituitary adrenal axis. Since the amount of cortisol hormone increases in the morning, we can wake up easily from sleep by becoming alert. On the other hand, melatonin hormone production increases at night and the amount of cortisol hormone decreases. That is why we fall asleep at night.

Why is this rhythm so important?

Circadian rhythm is a rhythm that suggests that we should not wake up at night and go to sleep early. Now you may be thinking, what will happen if we sleep a little late at night? If you pay attention, you will see that if you do not sleep properly one night, you feel tired the next day, your productivity decreases, and you do not feel like doing anything. Do you know why this happens? We are so busy all day, as a result, our body cells get tired. Sleep acts like a brake for our cells. If we sleep on time, our body cells that get tired can be properly repaired and restore energy, and because of this, we can work the next day. Circadian rhythm is also very important in building our immune system.

Not only sleeping, but our metabolism, that is, the system that digests food, also follows the circadian rhythm. Our digestive system is more active during the day than at night. The enzyme levels that break down food and convert it into necessary nutrients are also higher during the day. This is why you should eat dinner early at night. Because the later you eat, the more time it takes to digest. On the other hand, if you eat at least 2-3 hours before going to bed, the food can be digested well, and this also improves gut health.

Moreover, productivity is also related to circadian rhythm. Since the secretion of cortisol hormone increases in the morning, our productivity is also relatively high at that time. As a result, if you can do studies, exercise or any important work at this time, you can do it with attention and perfection. If you sleep late at night and wake up late, then you will see that you may not be able to focus fully on work even if you try.

According to experts, sleeping late at night disrupts the balance of circadian rhythm, which can seriously deteriorate our physical and mental health. If we do not do our daily tasks at the right time, then various health issues can arise. For example, obesity, diabetes, sleep disorders, mental health concerns like depression or bipolar disorder, etc. are caused by the imbalance of circadian rhythm.

So finally, the advice is, never wake up unnecessarily at night. Also, never use your laptop or phone for too long at night. Instead, try to sleep early at night and wake up early in the morning. Respect your circadian rhythm. You will see, only then can you stay healthy.