Do you know what goes on in your brain when you sleep? Most people recognize that they feel better after a good night’s sleep. But what many people don’t realize is just how essential sleep is for cognitive function and overall health. In this blog post, we will discuss the benefits of sleep, the harm of not sleeping, and what happens to your brain when you snooze!
Your brain is highly active while you sleep
Did you know that there is tons of brain activity going on as you sleep? It’s different from the brain activity that goes on while you’re awake. When you sleep, your brain is working hard to process information and consolidate memories. This is why healthy sleep patterns are so important for learning and retaining information.
Sleep deprivation can have serious effects on brain function including consequences for working memory, attention, and emotional reactions. That’s why it’s important to address sleep disorders if you experience chronic trouble sleeping.
To understand sleep better, let’s look at the five stages of sleep.
What are the stages of sleep?
Through electroencephalogram (EEG) recordings that measure brainwaves, scientists have discovered our brains go through different sleep stages during a night of sleep. The brain produces brain waves of different frequencies during each stage of sleep. Each type of frequency is associated with a different stage of sleep.
NREM vs REM sleep
You’ve probably heard the terms REM and non-REM (NREM) sleep before. But what are REM and NREM exactly?
REM sleep is a stage of sleep associated with Rapid Eye Movements, to put it simply. The non-REM sleep stage is associated with little to no eye movement. Why is this important?
During NREM sleep, the brain is less active and the brain waves slow down whereas, during REM, brain waves are more active. NREM is considered a lighter stage of sleep while REM is considered deep sleep.
The 5 sleep stages
There are five stages of sleep. The first stage actually is not sleep at all, it’s what happens right before you sleep: wakefulness. Then there are three stages of progressively deepening non-REM (NREM) sleep stages followed by a REM deep sleep stage.
Once the brain has passed through all NREM stages plus REM, this is considered one “sleep cycle”. Each cycle lasts about 90 to 110 minutes. The brain will pass through around four to five sleep cycles on an average night of sleep. NREM sleep makes up about 75% of our total sleep time while REM makes up about 25%.
The sleep cycles are as follows:
- N1: Stage one is light sleep
- N2: Stage two is deeper sleep
- N3: Stage three is the deepest level of NREM sleep
- REM: Stage four is when the brain becomes highly active
The important thing for you to know about sleep stages and sleep cycles is that each time your brain passes through a sleep cycle during the night, the REM stage becomes longer each time. In other words, you will spend more time in REM sleep and less time in non-REM sleep as the night progresses.
So, why is REM sleep important?
The importance of REM sleep
Sleep specialists and health experts talk about REM sleep all the time. But what makes REM sleep so important?
During REM sleep, your brain waves appear similar to when you’re awake and your eyes move quickly in different directions. Your breathing and heart rate also increase while your muscles become temporarily paralyzed. REM sleep is also associated with vivid dreaming.
REM sleep allows our brains to consolidate memories and information and improve focus. It also has benefits for the immune system, helping you to stay healthy. Reduced REM sleep is associated with conditions such as high blood pressure and diabetes.
How lack of sleep affects the brain
Getting insufficient sleep does not simply mean you don’t get the good benefits of sleep. Not getting enough sleep can actually be harmful to cognitive and emotional functions.
When you’re sleep-deprived, it’s harder to focus, react quickly, or remember information. Sleep-deprived people tend to get more emotional and have less patience. Lack of sleep also can lead to slower reaction times (putting you at higher risk of accidents) and affects learning.
Research shows that sleep plays a huge role in memory consolidation, mental health, and the brain’s ability to process information.
How does sleep affect emotional well-being?
While sleep is essential for cognitive functions, it is also crucial for your emotional health. During sleep, there is increased activity in the amygdala, the part of the brain responsible for processing emotions. This may explain why dreams often have an emotional component.
You don’t need to be a sleep expert to know that how you sleep affects your mood the next day. This is because sleep, especially rapid-eye movement REM sleep, plays an important role in regulating and processing emotions.
Some researchers have theorized that sleep promotes connectivity between the amygdala (the structure in the brain that’s responsible for emotion) and the prefrontal cortex (the area of the brain that controls executive functioning).
Therefore, when you get normal sleep, you are better able to regulate your emotions because they are under the executive control of your prefrontal cortex. Conversely, when you don’t get enough sleep, the prefrontal cortex has a harder time regulating the amygdala and you may have difficulty controlling your emotions.
Sleep and mental health
Chronic sleep deprivation has been demonstrated to be strongly linked to mental health issues and psychological distress. Around 40% of people experiencing chronic insomnia also suffer from a mental health disorder.
Sleep deprivation can cause changes in brain function and neurotransmitter activity which can lead to moodiness, anxiety, and irritability.
Insomnia has been recognized as a risk factor for major depression and dysthymia, which is defined as persistent mild depression. There is sleep research that suggests the relationship between insomnia and mental health disorders can go both ways: mental health disorders can be both a risk factor and a consequence of disordered sleep.
How does the brain control the sleep-wake cycle?
The hypothalamus is the region in your brain that contains a group of nerve cells that act to regulate sleep. Specifically, the suprachiasmatic nucleus (SCN) is a group of brain cells that control the circadian rhythm.
Other structures in the brain that are responsible for the sleep-wake cycle include the brain stem, thalamus, pineal gland, basal forebrain, and amygdala. We’ll briefly explain how each structure is involved:
- Thalamus: relays sensory information, is active during REM sleep but quiet during NREM sleep
- Pineal gland: produces the hormone melatonin which plays an integral role in sleep
- Basal forebrain: releases adenosine which acts as a nervous system depressant, can be counteracted by caffeine
- Amygdala: processes emotions and becomes active during REM sleep
Sleep is an essential aspect of overall health
Sleep is an essential part of our lives, yet it remains one of the most mysterious. We now know that our brains are highly active while we sleep and that lack of sleep can have a significant impact on mental health. The five stages of sleep play an important role in restoring energy, consolidating memories, and regulating emotions. REM sleep is especially critical for emotional well-being.
Luckily, it is possible to influence your sleep. Breathing plays a crucial role in improving your sleep quality. By slowing down your breathing, for example by doing a breathing exercise, you can relax your body and mind and fall asleep faster.
Today there are tools that exist to help you regulate your breathing. An example of such a tool is Somnox. This huggable sleep companion measures your breathing rate in order to regulate and slow down your breathing. You automatically enter a relaxed state of mind to help you enjoy a peaceful rest at night.
Curious to see if Somnox can help you sleep better? Take the sleep quiz to find out.