How is your REM sleep? If you're feeling tired you might not be getting enough.
A 2021 phone poll revealed that only 34% of Americans "sometimes" remember their dreams. About 1 in 10 say they "almost always" can, and the same percentage say they "never" do. Explanations for such varied recall abilities come down to the quality of one's sleep, the number of hours one spends sleeping and during what stage of sleep one wakes up.
REM sleep is the stage in which one dreams and it gets a lot of attention, often from those looking to improve their sleep. But experts say all stages of sleep are important for getting proper rest, rejuvenation and development.
What is REM sleep?
REM (rapid eye movement) sleep is a stage of semi-deep sleep, often referred to as “paradoxical sleep,” and is "a state of sleep when brain activity shows similar patterns as being awake," says Wendy Troxel, PhD, a sleep expert at the RAND Corporation and author of “Sharing the Covers: Every Couple’s Guide to Better Sleep."
According to the National Institute of Health, the initial stages of REM sleep occur about 90 minutes after falling asleep and come and go throughout the night.
What Happens During REM Sleep
During REM sleep, one's brain is very active, "but the body is essentially paralyzed," or in a state of sleep paralysis, says Troxel. That state of being is important, because REM sleep is also the sleep stage in which most dreams occur, so one's muscle paralysis is believed to be the body's way of protecting itself from acting out one's dream. "Dreams do occur in other stages of sleep," explains Troxel, "but the most vivid and often bizarre types of dreams tend to occur in REM."
Indeed, people who wake up during other sleep stages can rarely recall what their dreams were about. But one study found that a whopping 80% of people who wake during the REM phase of their sleep can remember their dreams well.
The REM stage of sleeping is also when other vital functions occur. "REM sleep is particularly important for memory consolidation, emotional processing and brain development," says Troxel.
During a full night's rest, most people experience five stages of sleep: Stages 1 and 2 are considered lighter sleep phases where one drifts between being asleep and being awake. Stages 3 and 4 are where the deepest levels of sleep occur; they are considered the "healing" stages of sleep as that's when breathing, body temperature, and one's heart rate are at their lowest levels and one's muscles are relaxed enough for tissue growth and repair to occur. REM sleep is Stage 5, and exists somewhere between the body's deepest levels of sleep and wakefulness.
"We enter sleep in the lighter stages of non-REM sleep and slowly descend into the deeper stages of non-REM sleep, followed by an episode of REM, and the cycle repeats several times throughout the night," explains Troxel.
And just as a healthy eating diet is not comprised of any one food group alone, "healthy sleep is comprised of all stages of sleep, including REM," explains Troxel. "It's a myth that REM sleep is more or less important than any other stage of sleep, including light or deep non-REM sleep."
How much REM sleep do we need?
The amount of REM sleep one needs varies with age. While brains are developing, such as in children and infants, more REM sleep is needed. Newborn babies are thought to spend about 8 hours in REM sleep every night. But people require less REM sleep as they age and most adults average only about 2 hours of REM sleep each night.
What's more, just because some people who wake during a REM stage of sleeping often remember their dreams, doesn't mean that failing to recall one's dream is any indication that you aren't getting enough REM sleep – you may have simply woken up during a less dreamy stage of sleeping.
"Rather than getting too hung up on whether you are getting enough REM sleep or deep sleep," advises Troxel, "the best strategy is to follow some basic healthy sleep habits which promote overall good sleep quality during all sleep stages."
Such healthy habits include adhering to a consistent sleep schedule, following a familiar wind-down routine every night before bed, keeping the lights low in the evening and avoiding alcohol, caffeine or exposure to the blue light of technology too close to bedtime. "Our bodies and brains function optimally when we achieve adequate sleep duration," Troxel says. "That's sleep that is appropriately timed, relatively consistent and is of good quality."
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This article originally appeared on USA TODAY: Am I getting enough REM sleep? What is REM sleep? Questions answered.