REM Sleep Explained

September 05, 2022

There are many complex processes at work when our bodies are asleep. Scientists have an increasingly better understanding of how the brain functions and how important good sleep is, however, this is still probably just the tip of the iceberg.

The brain is never actually asleep. A great deal of activity goes on in our brains when we retire at night in order for us to experience the restorative properties of a good night’s sleep.

All stages of sleep are important, but it is REM sleep that is necessary for cell repair, restoration and emotional processing. While REM sleep can happen throughout the night it is most active at the end of the night so if you are not sleeping enough, you are not getting enough restorative REM sleep.

Advances in brain polysomnography in the 1950’s lead to our current understanding of what happens in the brain as we sleep. The complex structure of how the brain operates on sleep mode is called Sleep Architecture and has been divided into five stages for better understanding.

When we go to sleep our brain progresses through five stages of sleep:

Stages 1 & 2, light sleep begins the process of slowing brain waves;

Stages 3 & 4 known as slow wave sleep [SWS] or deep sleep follows;

Stage 5 or rapid eye movement [REM] predominates in the last third of the night.

The preservation of this natural brain rhythm of sleep or sleep architecture is every bit as important as the overall sleep time. We need to experience all five stages of sleep in order to wake rested.

In Stages 1 & 2 the mind is in a light sleep, easily roused. Stages 3 & 4 are a deeper level of sleep where rousing is more difficult, and people report feeling disoriented if awakened. In Stage 5, or REM sleep, the brain activity is similar to that when awake but the body remains in full muscle paralysis except for respiratory and cardiac function. This allows the mind to experience a full dream without consequent bodily movement.

These stages are not experienced in chronological order but cycle throughout the night. REM sleep begins around 90 minutes into sleep but has much more prominence in the later part of the night. Unfortunately, this is the part that is most at risk of being lost if you are not sleeping well or long enough, says psychologist Rubin Naiman, a sleep and dream specialist at the University of Arizona Center for Integrative Medicine and the author of a recent review about dreaming published in the Annals of the New York Academy of Sciences.

Positive REM sleep is associated with an increase in growth hormone, a decrease in cortisol, learning and memory consolidation and even associated with healthy immune function response. While we still don’t know a lot about how the brain functions, we do know how to promote more REM sleep. It starts with focusing on healthy sleep patterns, diet, use of a sleep mask to eliminate light and maximize natural melatonin production.

To obtain a good night’s sleep it is very important to avoid factors that disrupt sleep architecture. Our sleep environment, the medication we take, our diet and our thought patterns can directly impede sleep patterns. The good news is; however, these factors are eminently within our control to change and the preservation of constructive sleep architecture will result in better sleep.

The importance of sleep and specifically Stage 5 REM sleep goes far beyond rest and relaxation. Our maintenance of good health depends upon it.