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What Is REM Sleep?

If You Always Feel Groggy, You Might Be Missing Out on This Specific Type of Sleep


For you, getting to sleep may be simple: head hits the pillow, eyes shut, lights out. Or, if you're like me, it's more like: head hits pillow, eyes shut, mind races for 45 minutes, then lights out. But whether you immediately doze off or toss and turn for hours, sleep is a lot more complicated than you may realise. There are four stages of sleep that you go through every night in two basic states: non-rapid eye movement (NREM) and rapid eye movement (REM). Though the terms may suggest otherwise, you start out in a lighter NREM sleep and then transition to a REM sleep, which is usually where dreaming occurs. It's this deep REM sleep that's vital for your brain and overall health.

Curious whether it's possible to feel better rested, POPSUGAR asked sleep experts how REM sleep works, why it's so important, and how to make sure you're getting enough.

What Happens During REM Sleep?

"Unlike other stages of sleep, which include movement and turning, the body is very still during REM sleep," Rebecca Robbins, PhD, a postdoctoral fellow at the NYU School of Medicine and a Beautyrest sleep expert, told POPSUGAR. However, "the brain is highly active."

During REM sleep, your brain takes all the information it picked up during the day, stores it, and rests up for the next day. (Think of it as clearing your brain cache the way you would clear your computer's browser history.) It's the most common stage of sleep for infants and decreases as we age. "REM aids the growing and developing brain by providing the neural stimulation that newborns need to form mature neural connections," said Nathaniel Watson, MD, the codirector of the University of Washington Medicine Sleep Centre, an expert for SleepScore Labs, and the former president of the American Academy of Sleep Medicine. Since everything is new to an infant, it makes sense, then, that less REM sleep is required as you grow older.

But REM sleep does a lot more than file away new information and skills. "The function of REM sleep includes benefits in terms of learning and memory consolidation, balanced mood, and general restoration of the brain from the prior day," Robbins said. In other words, it can be a big problem if you're not getting enough of it.

How Can You Make Sure You're Getting Enough?

On an average night of seven to eight hours of sleep, "a healthy sleeper will enter REM sleep between four and five times," Robbins said, noting that it makes up about 20 to 25 percent of adult sleep. If you're ever feeling cranky, irritable, and fuzzy when going about your normal day, it may be that you didn't get enough REM sleep the night before. Another side effect of not getting enough REM sleep? Increased appetite, Dr. Watson said, which means your ability to maintain a healthy weight is closely linked with sleep. (After all, it's tough to cut back on calories when a lousy night of sleep has you cruising for day-old birthday cupcakes in your office kitchen at 10 a.m.!)

If you want to cash in on that deep REM sleep, you'll have to plan for it. "REM sleep occurs more toward the end of the night, so avoid very early wake times to ensure you are not truncating your REM opportunities," Dr. Watson said. That means going to bed early enough that you can get your roughly seven hours of sleep before they're disrupted by an alarm or your kids.

Robbins adds that practicing good sleep hygiene can help you fall asleep and stay asleep. "Keep a consistent bedtime schedule," she said, even on weekends. "Get 20 to 30 minutes of daily exercise, avoid excessive caffeine, and try to keep electronics and other sources of blue light out of the bedroom."

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