Stop what you are doing.
Look around.
Think for a moment.

What can you see? Plants bloom in the spring, produce fruit in the summer, die in the fall, and the snow falls in winter. The sun rises in the morning, and sets in the evening - everything, EVERYTHING happen in cycles. Cycles are important for every living organism. To know when to hunt, when to mate, when to plant crops, and when to go to sleep. Our whole life happens in cycles. We wake up, and we go to sleep. Did you ever think what would happen if you just refused to sleep? Well, I will tell you: you would DIE. Why? We will get to that.

Circadian Rhythms

One of the most basic relationships that living things have with time is the circadian rhythm. It refers to the day - night cycle and can be observed in plants, animals, fungi, and interestingly, even in bacteria. Time is the fundamental part of the evolutionary process of all living things. Circadian rhythms are defined as physical, mental and behavioral changes that roughly follow a 24-hour cycle, responding to light and darkness in the environment.
But why is this important for us? Well, firstly, all of your organs follow the circadian rhythm. Each of your organs is the most active at a certain time of the day, and even certain diseases worsen at different times, based on which organs they affect. But more importantly, light and darkness trigger the release of some hormones, mainly melatonin, which has a huge importance for our lives. Melatonin is released in the dark, when the sun sets and you turn off the lights. Melatonin basically tells your body that it is the time to go to sleep. Although, that is not it’s only function. Melatonin is also a powerful antioxidant that helps repair your DNA while you sleep. But remember, melatonin is only released in the dark. Every time you look at your phone before going to sleep, every time you turn on the light when you want to go to the bathroom in the night, your melatonin levels are disrupted and cannot fully be restored again. That means that falling back asleep is much harder and also that it cannot carry out its function as an antioxidant. In addition, every light that shines while you are sleeping (those that blink when your computer is on standby, for example) disrupts your melatonin levels and makes you tired in the morning.

The importance of sleep

Okay, so now we know, that the hormones released during our sleep are essential to our lives, and we know that the sleep itself is very important too. But why is it important, and what happens when we sleep?
To start with, our sleep has two main phases - REM (rapid eye movement) and NREM (non rapid eye movement). They alternate throughout the night.
During the NREM phase our body is fast asleep, and it’s very hard to wake us. When we are the most tired, the NREM phase is the longest, and when the body has had some rest, the NREM periods shorten and REM phases elongate. During NREM phases we do not dream.
All dreams happen during REM, and we dream every night, even if we do not remember the dreams. As the name says, our eyes move during the REM phase, but they are the only things that can - the rest of your body is “blocked” so that it cannot move during your vivid dreams. Your body needs REM sleep. If you get less of it one night, your body will compensate the next night. If, for some reason, you could not get enough REM sleep, you’d go crazy in less than a week.
So what exactly do we need the sleep for? Actually, no one knows. There have been multiple theories but all of them turned out to be wrong.
One thing is for sure, sleeping is essential to our life...which brings us to the first question - why would you die, if you didn’t sleep?
No one knows.
But you surely would.

Did you know?

The easiest way to remember a dream is to wake up during the REM phase - you remember most of the dreams when you wake up and forget most of them within the next five minutes. You can remember most of the dream by thinking about it or telling it to someone.
When you wake up during the REM phase, your body can sometimes stay paralyzed - you cannot move at all and can even see or hear weird things. Scary, isn’t it? This is called sleep paralysis.
It can also happen the other way round - you fall asleep, but your body isn’t blocked yet, this can cause random movements during a dream that can wake you up

by Daniela Kročianová

Year 2, Issue 1