5 Facts About REM Sleep No One Ever Tells You

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Even though our brains mercifully shut off when we're actually asleep, sleep itself has got to be one of the most perplexing human experiences out there. Is my sleep good enough? How do I get more? You might know that when we sleep, we go through various stages of brain activity, from stage 1 to REM, or rapid eye movement, sleep, which is the deepest part of the sleep cycle. These stages repeat multiple times throughout the night, and you doubtless know a few things about them: like the fact that REM sleep is when you have dreams, for instance. But these seven facts about REM sleep aren't widely known, and deserve a lot more attention.

Researchers first discovered REM sleep in 1953, according to the National Sleep Foundation, and since then, we've made a lot of scientific headway into uncovering how the sleep cycle works. We're now in an age where smartphone monitors and smart beds help us monitor our sleep quality, identifying when we enter deep sleep overnight — though the helpfulness of these sleep trackers is debated. If you're hungry for information about how you sleep and how it affects your health and waking life, prepare to learn a lot about the REM sleep cycle you never knew before.

1. REM Isn't The Only Time When You Dream

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We're generally told that REM sleep is when we do our dreaming, but that's not strictly true. While it's the period where the majority of dreams happen, dreams also occur in non-REM, or NREM, sleep. In a study published in 2016, people who were woken suddenly from NREM sleep were often able to talk about the dreams they'd just been having, suggesting that NREM sleep also contains dreaming periods. Interestingly, those people who'd dreamed had brain activity during their NREM sleep that was pretty close to being awake; in other words, they were in a more "awake" state while they were having their dreams. This explains why you can feel as if you've had a dream just as you're drifting awake in the mornings.

2. Genetics Play A Big Role In How We Sleep

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It's now widely known that sleep hygiene can affect how you sleep at night, but did you know that your genetics also play a big role in your sleep cycles?

"Scientists have identified several genes involved with sleep and sleep disorders, including genes that control the excitability of neurons, and 'clock' genes such as Per, tim, and Cry that influence our circadian rhythms and the timing of sleep," explains the National Institute for Neurological Disorders and Stroke. Huge genetic studies have found that sleep disorders such as insomnia are highly linked to your genes, and that there's a big overlap between genes involved with neuropsychiatric disorders like depression and genes that involve insomnia. If you sleep poorly, there's a strong chance your relatives do, too.

3. REM Sleep Seems To Have A Strong Role In Memory

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It's suggested that entering REM sleep helps your brain do something known as "memory consolidation", where it cements the events you've experienced in your long-term memory.

"REM sleep is thought to play a role in memory consolidation, the synthesis and organization of cognition, and mood regulation," explains the National Institute for Neurological Disorders and Stroke. Extra evidence for this was found in a study on rats, published in 2016, where neurons involved in REM sleep were shown to be necessary for remembering something the day after it happened.

4. All Sleep Stages Help Cognitive Function

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A lot of attention is given to REM sleep, but all the levels of sleep work together — both to give us refreshing sleep, and to help our brain function. A study in 2018 suggested that we experience NREM and REM sleep in turns to help us solve complex problems: during NREM sleep, we replay specific memories, then during REM sleep, we play a whole random range of them, which may help us see connections and observe solutions to big issues in our lives. A study published in 2014 also suggested that both kinds of sleep help the brain recover from the activities of the day in different ways.

5. Having Prolonged REM Sleep Issues Can Be Damaging To Your Health

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People who don't get enough REM sleep for a long period can feel the affects in different ways across their body. Research indicates that chronic REM issues are linked to a rise in serious migraines or a heightened risk of Parkinson's disease. These appear to be influenced by the neurological impacts of lost REM sleep over time.

The REM cycles of sleep are fascinating, and scientists are still discovering how they affect our waking lives. For now, enjoy your dreaming — and the healing your sleep cycles bring.