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Why Do We Sleep At Night?

Why do we Sleep at Night?

why do we sleep at night

why do we sleep at night


Actually the right question that we have to ask ourselves is not; “why do we sleep at night?” but to ask; ‘why do we need to sleep at night?’. Usually known, people always ask why we are able to give up on our biological needs such as; food, sex… etc. for few days. While, it is almost impossible to give up sleep for days. It does not matter how much caffeine you take, we just get broken the moment we feel sleep. But, why do we (and many other animals –but bats-) sleep at night from the first place? This is going to be our main theory and main question that we aim to answer in this article today –or tonight-.

Let me give up on few hours to make all my researches for you and tell you why do we sleep at night. the reason that brought me to write this is when I broke last night; when I was writing the previous article (myths about sex). I could not continue writing in a moment when I felt completely sleepy.

As human beings, we realized in a stage that sleep makes us feel ‘better’. In other case, if we do not sleep it makes us feel ‘worse’. This fact pushes us to ask the questions “why do we sleep at night? Why do we need to sleep at night?

To say that we sleep because we feel drowse, is not a satisfying question. Also, you may think that reason of why do sleep at night is because we need relaxation for the busy hard day. Actually, sleep gives the body only 50 calories, which is the same amount of a piece of bread. In general, our muscles need rest, but sleep does not affect this anyhow. The body only needs to know that you are relaxing, either sleeping you are or just sitting. The brain also needs rest.

So, why do we need to sleep? ; A question that confused scientists for ages. That is why they spent decades and years studying this activity. They tried to look at the topic from its different views. They used different kind of experiences in order to analyze it enough. They studied the difference of sleep between human and animals. Even this whole amount of experiences and studies and researches, the question why do we sleep at night remain hard to be answered. This is so confusing for the people and scientists as well.

However, today I came to give the most logical and known theories about it. The difficulty of this question to be answered does not mean that the scientist efforts were for nothing. In fact, they could make us know a lot about sleeping and its functions. And this hardness of the question leaded to make three theories about why do we sleep at night, which are to be included in the following parts. Even that the scientist will not unite under one theory, they still cooperate to find the exact and final fact about it.

The main four theories of why do we sleep at night:

  • Inactivity theory:

It is one of the oldest theories about sleep. It is called as well as the theory of adaptation or the evolutionary theory. It says that the keeping calm and with no actions during the night, is the thing that let the creatures to live and survive through time. This period of the day that provided the creatures to hid from danger and remain alive is at night. This is how they could stay out of danger. The theory says that the creatures that used this period of the day to keep calm and stay hidden could survive and live better than others, which were more active at night. The inactivity of these creatures let them stay away of accidents. So, this character evaluated through the ‘natural selection’ and could stick to the creatures. This character evaluated to become what we know now as ‘sleep’.

This is what the ‘inactivity theory’ says about why do we sleep at night. Now let us move to the next theory.

  • Energy Conservation Theory:

Even it can be less obvious for the people who live in the places that are characterized by rich sources of nutrition. One of the strongest and most powerful factors of the ‘natural selection’ is the competition and use of the energy sources. This theory suggests that the main function of sleep is to conserve the energy. The goal is to lower the demand and needs of energy and costs during night. Especially in a place where the nutrition and foods are somewhat rare to find.

The studies show that there is a big decrease in the metabolism during sleeping (about 10% among humans and other creatures). For example, the need and demand for the calories during sleep reduces, comparing to the awakening. Those proofs do confirm the theory that says that the sleep helps the living creatures to conserve their energy. Many scientists see that this theory should be connected to the ‘inactivity theory’.

  • Restorative Theories:

In another explanation of why do we sleep at night, it is said that the sleep helps people to ‘restore’ their energy that was lost during the awakening period. The sleep provides the restoration and fixing to the body. In the last years, these ideas could be strengthened by some researches were done on humans and animals. The more surprising is that the animals that were kept awake and were prevented from sleeping, lost its immunity and died within few weeks. The other proofs that strengthen this theory is that all body’s functions such as; muscles growth, restoration of tissues, creating proteins, and releasing the hormones, usually happen during sleep.

  • Brain Plasticity Theory:

The current and most convincing explanations of why do we sleep at night is that sleep is associated with the changes of structure and organizations in the brain. This theory, which is known as brain plasticity, is not yet completely understood. Otherwise, its association with the brain carries a lot of effective effects. It is now more obvious that the sleep plays a very important role in the growth of brain among newborn and babies. The newborn babies stay for over 13-14 hours of sleep per day. During this period they usually are in the phase of REM (Rapid Eye Movement).  This phase is when most of dreams happen. The relation between sleep and brain plasticity became obvious among adults as well. This appears in the prevention of sleep. The affection of sleep on people’s abilities to learn and to do many tasks.

why do we sleep at night

why do we sleep at night


Although those theories remain uncertain, they could help the science make a very important move to understand what happens during sleep. And to know what are the mechanisms that control our daily activities. This article does not give an ultimate and specific answer of ‘why do we sleep at night?’, it only smooths the way to answer the question and to give a logic, right, and convincing knowledge about this important part of the human’s lives.

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