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How Sleep Works: The Science of the Sleep Cycle

There is no shortage of studies and statistics when it comes to the importance of sleep. But why exactly is sleep so essential for our health, performance, and general wellbeing and why sleep is? Sleep is a biological process that enables our body to restore itself after long hours of being awake and is how sleep works.

It does so by switching our brain into an alternate state where it shuts down unnecessary activities and triggers the release of hormones and natural compounds that help us recover.

This article will explain what happens during the different stages of sleep, as well as its benefits on our health and wellbeing.

Stages of Sleep

In order to better understand how sleep works, we first need to understand the stages of sleep.

The two main phases of sleep are REM Sleep and Non REM sleep. During REM sleep, the brain becomes very active and this is when most of our dreams occur. It is also when the body repairs itself the fastest.

Non-REM Sleep - This phase is characterized by lower brain activity, but the body is still very active. The exact role of non-REM sleep is not yet fully understood, but it is believed that it helps with regulating our hormones and repairing our immune system.

How does the body know when to sleep?

Sleep is not a biological process that happens automatically. It is triggered by certain biological cues and cycles that our body follows daily.

The main cue here is the change in hormone levels. In a nutshell, our body has a natural clock that follows a daily rhythm that is often referred to as our circadian rhythm.

The circadian rhythm regulates the daily cycles of all our bodily functions, including sleep, so it is very important for our health that we keep it on track.

The circadian rhythm is regulated by sunlight and the fluctuations of our hormones, mainly melatonin and cortisol.

When sunlight hits our eyes, a chain of reactions happens in the body, and melatonin levels are decreased.

When melatonin levels go down, cortisol levels go up, and this is the signal to our body that it is time to wake up.

What happens when you sleep?

When we sleep, our body goes through various cycles, taking us through all stages of sleep.

During the first couple of hours, our brain waves become slower, and we gradually drop into a state of being asleep.

This is the transitional period between being awake and being asleep. As we transition into the first stage of sleep, we experience a drop in heart rate, blood pressure, and body temperature, which makes us feel more relaxed.

In this stage, we are very close to being awake, so it is easier to be woken up. This is the stage where you might experience sleepwalking, sleep talking, and nightmares.

Benefits of a good night's sleep

Better Mood - Sleeping well has been shown to improve our mood by balancing the levels of serotonin and dopamine, the “happy” hormones. Sleep deprivation can lower these levels, making us even less happy than usual.

Stronger Immune System - Sleep is when our immune system is at its strongest, and it repairs itself when we sleep. Sleep deprivation has also been associated with increased risk of contracting certain diseases, such as colds and the flu.

Better Focus and Concentration - The brain is more active during REM sleep when compared to when we are awake. It has been suggested that this is the reason why dreams can be so vivid, and why people who suffer from sleeping disorders have difficulty concentrating when they are awake.

Stronger Memory - During sleep, the brain goes through a process called “consolidation” in which it stores new memories and spares existing memories for long-term storage. - Increased Creativity

Many artists and scientists have reported being more creative when they were sleeping. This is one of the reasons why napping is highly recommended for creative tasks.

Weight Loss - Sleeping well can help you maintain a healthy weight and prevent weight gain. Some studies show that people who sleep less than 7 hours per night are more likely to experience weight gain, while those who sleep more than 8 hours per night are more likely to experience weight loss.

Better Sex Life - Lack of sleep has also been associated with lower libido and reduced sexual activity.

Why is Sleep Important for our Health?

Sleep is necessary for the body to restore and repair itself, and we have seen that it plays important roles in our mental health, mood, and creativity. But why exactly does sleep have to happen when we are resting and inactive?

When we sleep, the brain enters a state where it is less active and consumes less oxygen. At the same time, the oxygen supply in our blood increases.

This is why we are less likely to wake up when we drink coffee when we are sleeping, compared to when we are awake.

This process of resting and becoming less active is also a way for our body to save energy, and this is important because we can't survive without sleep, no matter how strong we are.

The Dangers of Not Getting Enough Sleep

As we have seen above, sleeping is a very important activity for our health, and it has many benefits. However, if we do not get enough sleep, we are putting ourselves at risk of experiencing several negative health outcomes.

Depression and Anxiety - Getting enough sleep improves our mood, and it has also been shown to reduce the risk of experiencing depression and anxiety.

Diabetes - Studies have found a positive correlation between poor sleep and an increased risk of diabetes.

Heart Disease - Studies show that not getting enough sleep can increase levels of bad cholesterol and blood pressure in the arteries, which puts a person at risk of developing coronary heart disease.

Weight Gain - We have seen above that sleep has a significant impact on our metabolism, and a lack of sleep can increase the risk of gaining weight.

Increased Risk of Dying - A study that followed over 1 million people for over 10 years found that those who reported sleeping less than 7 hours per night had a higher risk of dying from all causes, compared to those who had slept for 8 hours per night.


Sleep is an important part of our daily lives, yet it is often overlooked. It has many benefits for our mental and physical health, and is necessary for our bodies to function properly.

If you have been struggling to get a good night's sleep, or you feel like you aren't getting enough sleep, it's important to understand what may be causing the problem.

If you have tried everything and are still not getting enough sleep, it's important to talk to your doctor. And remember, getting enough sleep is crucial for your health and wellbeing.

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