Why do we need Sleep and how it Works

Explained benefits of Sleep

Photo by Mark Tegethoff on Unsplash

If no one explained this to you before, you should know that sleep is extremely important. How important? Just remember that sleep takes 1/3 of your lifetime on Earth, so it’s about 30 years or life important.

The truth is even science didn’t know so much about sleep 50 years ago, but now they do.

It’s a fact now that sleep played a major role in human evolution, and it’s time for you to understand why is as important as ever.

I will talk about:

  • Types of sleep
  • NREM sleep
  • REM sleep
  • Afternoon naps

Are you ready? Let’s roll.

1. Types of Sleep

Sleep, as there is a chance you already know, it’s divided into 2 major parts, and that fact stands both for human and animals.

From the moment you finally shut your eyes, until you wake up, your brain takes a journey through:

  1. NREM sleep — Non-Rapid Eye Movement
  2. REM sleep — Rapid Eye Movement

In the first part of the night, our brain dives into NREM sleep. This is where the most profound sleep occurs and it’s also divided into 4 stages of depths.

Keep in mind that even it’s also called Deep Sleep, your body still carries some muscular function active. Your body tonus can still be captured using electronic sensors.

As the sunrise gets closer, our sleep moves into the next stage: REM sleep. As you might have already figured out, this is the part of the night when it’s really hard for someone to wake you up. But why during this stage is so hard to wake up if the previous one was called the Deep Sleep?

The answer is not so hard to understand, but you have to bear with me for a while.

NREM and REM sleep can be distinguished by the brain's activity during the night and its electrical signals.

Imagine a stadium filled with 50.000 people, and place a microphone above the field. Now, all these 50.000 are talking to each other using different tones, volumes, maybe even language. Every 2 people have a very different conversation subject. Doesn't matter which technology you use, the noise will be chaotic. — This is how your brain works while being awake and it makes sense. We all have different voices talking at once in our heads, and sometimes a random song pops up.

When we are in the NREM sleep stage, it’s like everyone gets up to sing the national anthem. All those random voices get together into one, very well-coordinated and synchronized voice. — If you convert the electrical signals into a song, the song will make sense and it will even be predictable.

Moving to REM sleep, things change again. The anthem is finished and everyone starts chatting again. On the plus side, more people get to the stadium. More noise, more chaos. - This is because in the REM sleep stage the brain can be even 30% more active than it was when you were awake.

Because of this intense activity, the brain basically disconnects the body. Your body's nervous system doesn't receive any command, so the tonus it’s all gone. In this stage, every stimulus that comes from outside it’s filtered. A part of the brain has to decide if that stimulus is important enough to wake you up or not. So, you are not sleeping deeper, it’s just the brain that doesn’t respond as normal.

Don’t worry, necessary muscular activities, like breathing, still continue.

Electrical activity of your brain during stages of sleep

2. NREM sleep

During the day, our hippocampus(the short-term memory brain part) is filled with new information, and unfortunately, it has limited space. In order to permanently memorize what happed during the day, the information must be transferred into some other part of the brain.

This, as far as science got to this day, is the main purpose of NREM sleep. As we fall asleep our brain starts analyzing what we’ve learned and selectively moves the information into the permanent storage zone. In other words, this is also the time when we forget things. Given the fact that our brain space is limited, not everything we learn is useful for the long run. Even more, the capacity to forget it’s a good defense mechanism against trauma.

The cool thing is that a 2009 experiment proved that we have, to some degree, control over the things we forget and those things we remember.

3. REM sleep

Have you ever felt asleep being unable to solve a problem, but as soon as you woke up you just happened to know how to solve it? If the answer is yes, it means you had a night of very good REM sleep.

During NREM sleep, we improve our database. When that process is finished, our brain gets even busier. Using every information already stored inside(even something learned a month ago), it starts making random connections between them. Of course, it’s much more often that the brain reviews the day that just ended, that’s why we sometimes dream about what we did in that day.

Now, remember what I’ve explained earlier when I said the body gets disconnected from the brain during REM sleep. It’s not because what we dream seems so real, it’s because the brain is very active and if those electrical imposes would reach the body, you will start doing what you are dreaming, but with your eyes closed.

We all want to dream about some great car race or mounting climbing, but if the brain would keep the body awake or responsive, you will try to climb your furniture or even reach your car, completely unaware of what it’s truly happening. It’s dangerous, and nature knew that.

4. After-noon Naps

Almost everything that the modern world thinks about sleep it’s wrong. When talking about sacrifices, sleep it’s our first choice. Less sleep, more success, they said. But after around 15–16 hours of being awake, the brain stars ~mulfunctioning~. In several experiments, scientists proved sleep-deprived people have a much worse brain response than drunk people, the memory power drops a lot, and the worst of all is that the concentration power it’s almost completely gone. In the USA, the are more car accidents per year caused by people falling asleep while driving than accidents caused by people who are drunk or under drugs influence.

Why? The answer is simple. If you are drunk or high, your brain reflexes are slowed down, but they still work to a very small degree.

If you are sleep-deprived and you shut your eyes even for 2 seconds, there are no more reflexes or responses. You can’t see, you can’t focus, you can’t react.

In order to avoid sleep deprivation, humans must sleep at least 7–8 hours per night. Every amount under this average will still make the brain works as you have been awake for 24–48 hours.

In a previous article, we stated that the need for sleep changes over the years. This fact is now being reviewed again by science and some result indicates that the same amount of sleep is necessary the entire life, but the aging factor ruins our ability to sleep.

Because of this sleep demand, nature comes up with after-noon naps. This natural need to shut the eye during the day it’s even imprinted into our DNA, and it’s most active during a specific period of the year.

In the afternoon, after you grabbed some lunch and you feel sleepy, it’s not because of the food itself. It’s actually you're built over the centuries' DNA asking you to take a nap.

If we knew about this during the industrial era, maybe we might have built our social habits in a different way.

Another interesting fact it’s that those night owl, as society named them, aren’t lazy bastards. Only 40% of the society it’s naturally built to wake up early and go to bed early.

In the early days, when communities just started to form, the need for security increased. The community members used to split into 2 groups: the first group would go to sleep early, the second group was in charge of the security during the night. As the morning comes, the first group would wake up and the second would go to sleep, this method providing security for almost the entire night.

This method is still applied today. Some cops still work at night, aren’t they?

I hope you love this article and it comes in handy!
Most of the information comes from Matthew Walker’s book, called Why We Sleep



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