Why You Need REM Sleep

Why You Need REM Sleep

Sleep is very important for the body and the mind, and a lack of it can lead to problems concentrating, decreased memory, irritability, and depression. REM sleep is a very important type of sleep for humans. But just what is it, why do we need it and what do experts have to say about it? Read on to find out.

What it is REM sleep?

There are five stages to the human sleep cycle. The last stage of sleep is known as REM sleep. REM stands for Rapid Eye Movement. This fifth stage of sleep gets its name from the rapid back and forth movements of the sleeper’s eyes. When a person falls asleep, they progress from the first stage of sleep to the fourth stage. During each of these first four stages of sleep, the heart rate continues to slow, blood pressure decreases, and the body remains mostly still. While these stages progress in order from one to another, the REM stage of sleep is quite different.

A person usually has between three and five periods of REM sleep each night. They occur at intervals of 1-2 hours and differ in how long they last[1], but account for around 20% of the total time spent asleep. REM cycles usually get progressively longer throughout the night and normally occur close to morning. While the mind is highly active during REM sleep, the body is immobilized. It is believed that this immobilization is to prevent the person from moving in accordance with in-dream activities. While major muscles are paralyzed, the face, legs, and fingers will twitch during the REM cycle. The amount of REM sleep varies with age and is highest in infants and the elderly, with a decrease in adolescents and young adults.

There are many other differences between REM sleep and the other four stages. During REM sleep, the large voluntary muscles of the body are paralyzed[2], brain activity becomes more intense, and dreams occur. Also during REM, the heart rate increases and breathing becomes faster and more irregular than during NREM (non rapid eye movement) sleep[3]. Other effects of REM sleep include Arousal of the sexual organs of men and women, which can last from one to over three hours.

Why do you need it?

While the physical effects of REM sleep are well known, its function is not well understood. It is clear that REM sleep is important for memory, learning, and mood. People suffering from depression often have shorter REM cycles that those who do not. This cycle is thought to be the period memory consolidation takes place. The brain uses this time to organize, categorize, purge, and store memories and concepts that have been learned. It is also associated with creative thinking in the brain.

REM sleep is so important that a lack of it can be deadly. In a sleep deprivation study in rats, deprivation of REM significantly shortened the life span of the test animals. Rats typically live for about four years. This study found that rats that were deprived of REM sleep lived for only five weeks, only two more weeks that those deprived of sleep entirely. The rats also had low body temperatures and suffered from sores on their bodies. This is clear evidence for the importance of REM sleep for the body.

REM theories

Because many aspects are not well understood, there are many theories about REM sleep that are yet unproven. Below are two interesting theories.

David Maurice, PhD, a professor of ocular physiology at Columbia-Presbyterian Medical Center has his own unique theory as to the purpose of REM sleep. He posits that the rapid eye movement associated with REM is for the purpose of stirring the aqueous humor, a chamber behind the cornea, in order to keep the cornea supplied with oxygen while sleeping. The theory goes that if the eyes remained still during extended periods such as while asleep, the cornea would be starved of oxygen, so REM solves this problem. He developed this theory after wondering why animals born with sealed eyelids and fetuses in the womb have high amounts of REM activity. He used a mathematical model to determine that resting aqueous humor would not be able to supply sufficient oxygen to the cornea while resting for extended periods[4].

Joe Griffin also has a unique theory of the purpose of REM sleep. His theory is called the Expectation Fulfillment Theory of Dreaming. This theory states that dreams are fulfillments of our waking desires. By acting out our daily desires that go unfulfilled while dreaming, we deactivate the emotional arousal in order to move past it[5]. Basically, this is the theory that dreams play out our true desires. The brain does this by using metaphors to diffuse emotions. Because the brain cannot build a world using the sense, as they are deactivated during sleep, it uses memories to construct realities based on the emotions associated with those memories. For example, if you felt betrayed during the day, your brain would match that emotional pattern with a memory you already had and use it to construct a dream that would help you deal with the feeling of betrayal.

Conclusion

While some aspects of REM sleep are understood, many are not. What we do know is that REM sleep is important in order for the body and mind to function properly. So make sure that you get plenty of rest, avoid or minimize interruptions to your sleep as much as possible, and give your body the chance to get the REM sleep that it needs.

Michelle Gordon is a health conscious researcher, reader and writer of all topics involving sleep. Including sleep habits, pillows, http://www.latexmattress.org latex mattresses, sheets and medications associated with sleep. She has studied the topic of sleep for over ten years and currently writes papers, and maintains several blogs about sleep.