REM vs. Non-REM Related Sleep: What You Should Know
Date Published

Non-REM sleep makes up about 75 to 80% of your night and includes the deep, restorative stages that repair the body. REM sleep, roughly 20 to 25%, is when most vivid dreaming and memory consolidation happen. You cycle through both about every 90 minutes, and you need each for healthy rest.
You may have heard the term “REM” sleep. REM stands for rapid eye movement. During REM sleep, your eyes move quickly in different directions. That doesn't happen during non-REM sleep. It’s a commonly used phrase but what many may not realize is the impact that it has on sleep quality. Whether or not it’s attained in a sleep cycle is imperative to a person’s overall health. Here’s what you should know about the type of sleep you may or may not be getting.
The Stages of Sleep
Stage 1:This is the first and lightest stage of sleep. It is non-REM. You might enter this stage as you nod off while reading a book before bed or watching a movie. It’s a relaxed state but can be easily disrupted, causing a sudden jerk if awakened.
Stage 2:This stage comes next and is slightly deeper. You are less likely to be easily awakened in this stage. The heart rate begins to slow as your brain prepares for REM sleep. Half of the sleep you experience in the night is in this stage.
Stage 3:If you’ve ever tried waking someone up and had a difficult time doing so, they are likely in stage 3. It’s harder to awaken if your sleep is disrupted in this stage. This is a stage of repair. Your body uses this opportunity to regrow and build tissues, bones and muscles. It can even strengthen your immune system. This is the most restorative stage. This is why getting quality sleep is so important for your overall health.
REM Sleep:At last, REM sleep occurs after about ninety minutes into the sleep cycle. This is known as the dream stage that is most often remembered. The REM stage increases in length with each cycle. The first period will only last ten minutes and will eventually build up to be one hour.
Sleep is complex in itself and adding in any potential sleep disorders that disrupt the cycle can have a significantly negative impact on your health. Sleep enables a person to be refreshed mentally and physically.
The benefits of reaching full sleep cycles include:
- Stronger immune system
- Weightcontrol
- Decreased inflammation
- Strengthened memory
- Better mentalhealth
- Healthier heart
- Higher emotional intelligence1
Dreaming
We all dream, even if we don’t remember the dreams. Dreaming is actually very good for your health. Persons with difficulty reaching or completing the REM stage have an increased risk of anxiety, depression, hallucinations and can potentially develop neurological disorders.
Non-REM Sleep
Calling the first stages all non-REM may imply that they are not as important. However, they are extremely important and are the reason why most of a night’s sleep is spent in these stages.
REM Sleep
If a person sleeps 6-8 hours a night, they will have gone through an average of 4-5 REM periods. The longest period will be at the end of the night, as the REM cycle expands in length each cycle. The brain is extremely active during this stage, more than any other point in the sleep cycle.
When undergoing a sleep study, sleep specialists will track the stages of sleep and how a person progresses through them. It’s through the overnight study that we are able to diagnose a sleep disorder. For example, a person with narcolepsy will go immediately into REM sleep, while a person with sleep apnea may never be able to truly attain a good cycle.
Now that we have covered the basics of what you should know about REM and non-REM related sleep, be sure tocontact uswith questions. Our sleep specialists are here to help!
- J Sleep Res. 2014 Dec;23(6):657-663. doi: 10.1111/jsr.12192. Epub 2014 Aug 13.
Frequently asked questions
Neither is better, you need both. Deep non-REM sleep repairs muscle and tissue and supports immunity, while REM supports memory, learning, and mood. A healthy night cycles through both several times; losing either stage leaves you unrested.
Most adults spend about 75 to 80% of the night in non-REM, including roughly 1.5 to 2 hours of deep slow-wave sleep. That is around 5 to 6 hours of total non-REM across a typical 7 to 9 hour night.
No. Most adults need closer to 90 to 120 minutes of REM per night across several cycles. REM lengthens toward morning, so cutting sleep short or fragmenting it, as sleep apnea does, tends to rob you of REM first.
Alcohol, irregular schedules, and untreated sleep apnea fragment your cycles and suppress REM and deep sleep. If you sleep enough hours but wake unrefreshed, a sleep study can show whether your stages are being interrupted.
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