What is REM sleep? It stands for rapid eye movement and is one of the five stages of sleep. As the name says, during REM sleep the eyes move rapidly side to side.
Each REM cycle compounds and lasts longer as the sleep progresses. REM makes up roughly 20-25% of a sleep cycle of the average adult and can typically happen around five times a night. Meaning that in the average night between 90-120 minutes of REM are experienced by the sleeper.
What does it do to you?
Rem sleep raises brain activity to levels similar to the awoken state. This is measured by oxygen and glucose metabolism tests and has proven that the brain uses equal if not more energy in REM sleep than when awake. It also increases blood pressure and eye movement but disables the rest of the muscles in the body, leaving them useless and paralysed. This phenomenon is known as atonia. It happens when a failure to stimulate motor neurons, required for movement of muscle, occurs in the brain.
It is thought that atonia occurs to prevent the body from acting out dreams during REM sleep to act as a self defence mechanism. However, some people may be immune from this paralysis and their muscles will continue to move during REM sleep. This medical condition is called REM behaviour disorder. Because of the paralysis of muscles, it is a common cause of snoring and other breathing problems during sleep.
Importance of REM sleep
A test to looking at the importance of this stage of sleep was conducted on rats. Doing so they were deprived of REM sleep. Where ordinarily the rats tested on had a life expectancy between 2 and 3 years, the rats who were deprived of REM sleep only lived for 5 weeks on average. This is a significant reduction of life. It is obvious why the test has not yet been conducted on humans. The rats also developed sores and low body temperatures all because of the weakened immune systems as a direct result of the deprivation.
Failing to get sufficient REM sleep has been proven to impair the mind’s ability to learn complex tasks. In particular, it is fundamental for memory consolidation, assisting the brain to sort out what is important or not to remember. It is at this point where wild dreams run free. Furthermore, the body will seek more REM periods in a sleep cycle if the subject is sleep deprived.
Furthermore, failing to get enough REM sleep can result in negative effects such as anxiety, irritability, hallucinations, impaired learning, drowsiness, seizures, difficulty concentrating and an increase in appetite. However, there are also few positives of REM sleep deprivation, these include; depression is supressed, supressed aggression, and eating behaviour is also improved.
It has also been hypothesised that the REM sleep stage is fundamental for development of neural connections in the brain. Evidence of this is seen at the reduced amount of REM sleep engaged in as a person ages, or as the brain becomes more mature. Waking up after REM sleep the mind may be in a hyper associative state. Meaning sleep promotes creativity and allows better free association for tasks such as problem solving or idea generation.
Effect of drugs on REM sleep
Antidepressants have been known to supress REM sleep. Nicotine has a similar affect, as heavy smokers often sleep lightly, with reduced amounts of REM sleep. They also tend to wake up after around 4 hours because of nicotine withdrawal. Furthermore, alcohol sometimes used by people to help them ‘fall asleep’ does just that but at the same time numbs them of brain activity and doesn’t allow it to function to its full capability during a sleep cycle, often preventing them from falling deep enough into sleep to reach the REM cycle instead it keeps the person in the lighter stages of sleep, in which they can easily be awoken from.
For tips on better sleep see “7 ways to better sleep”
Overall REM sleep is fundamental to a good night’s sleep and for both physical and mental health. Failing to get enough will be detrimental both short term and long term. To look deeper at the health risks click here.
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By Shane Finch