We are going to guide you through what happens at every sleep cycle stage and how it can affect your physical and mental health.

It is a widespread evil, but due to increased interest in the subject and the latest advances in the scientific field, it is finally possible to decipher some facts. Talking about an insomnia epidemic is no longer a cautionary tale. The number of people suffering from this disorder increases every single day.

But how can a night of “tossing and turning” be avoided?

Insomnia: Understanding a global problem

Pressured to find new and better solutions, scientists carry out more and more studies about sleep disorders and our sleep cycle, every day. But in order to really understand the science of sleep, we need to break it down.

Until the mid-20th century, people believed that during the sleep cycle the brain would shut down completely to recover. Nowadays, we know that we sleep to save energy, maintain our physical body and cement memory.

What are the physical effects of a sleepless night?

During a study carrying on by the University of Surrey, UK, in which scientists kept people awake for 29 hours. Later tests showed the number of white cells had increased as if they were fighting off infection.

Sleep deprivation leads our body to release hormones like cortisol and adrenaline, which make our blood pressure rise and you might have a sudden urge to eat carbs because your metabolism is out of sync.

The student Randy Gardner holds the record of being awake for the longest time. In 1965, he stayed up for a total of 264 hours, that’s 11 days. As his sleep cycle was more and more affected, Randy began to lose the ability to think, paranoia settled in and he started to see things that weren’t there.

At the end of the experiment, he slept for 14 hours straight. There were no signs of consequences.

The sleep cycle: what you need to know

Nowadays, we know that our sleep cycle has 4 different stages. The most interesting sleep cycle stage is the last stage – REM sleeping or Rapid Eye Movement when your brain activity increases, and dreams happen. You can see what happens to your body as you move through the different sleep cycle stages, in the picture below:

sleep cycle

Have you experienced living a moment during the day and that memory coming back exaggerated or distorted over and over in your dreams? It happens to everyone, it’s our memory working overtime while you sleep.

Why are memories sometimes distorted, spiced up with fantasies or with things that have never happened? There is a theory for that:  the Synaptic Homeostasis Hypothesis (SHY). It seems complicated but it isn’t.  It so happens that during sleep, the brain undoes some neurologic connexions, that is, it erases memories.

The body releases acid gamma-aminobutyric, a substance that weakens relations between neurons. Its goal is to free space and cerebral capacity so you can pursue the ability to learn new things.

During the sleep cycle, we need to determine which memories are the least important so the brain verifies their connexion with other information previously stored in your mind.

This “cleaning” of the memory happens just before dreams. So, it’s possible that when dreaming begins, the brain is still under the influence of memory defragmentation. That may explain the level of fantasy in dreams, but there’s no evidence of that.

The connection between memory and sleep

However, the connection between sleep, memory, and learning is highly acknowledged. Several studies about our sleep cycle show that our ability level to learn is higher in the morning, right after we wake up.

From another sleep cycle study, it was concluded that external stimuli during sleep can influence our learning. Psychologist Ken Paller led an experience where 50 volunteers went straight to sleep after seeing a sequence of images and sound.

During sleep, half of them received a sound stimulus in the third stage of our sleep cycle (NREM), the same sound associated with the images. On the following day, the volunteers took a memory test and the ones exposed to the sound during sleep were able to remember more images in the correct order.

We know it’s not possible to learn new things when sleeping.
However sleep can strengthen the memory of something we’ve learned awake.

We hope you have enjoyed our article about the Sleep Cycle Stages and what happens in each one. Feel free to pin all the images to your favorite Pinterest board and subscribe to our newsletter, so you can be the first to know about our latest articles. Lastly, don’t forget: sleep well, live well!

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