A growing body of research has made it clear that sleep health has a direct impact on your physical health. Among other things, regularly logging enough high-quality sleep is linked to a lower risk of developing chronic conditions like type 2 diabetes, heart disease, and high blood pressure. But there are many phases of sleep and, if you want to do a deep dive into how you’re faring, it’s fair to wonder how much REM sleep you should be getting each night.
It can be tough to calculate exactly how long you’re in REM, but many health trackers use your heart rate, heart rate variability, and data on your movements to make solid estimations. (Just know that this isn’t as accurate as getting a lab test done.)
Want to know whether your health tracker’s sleep report is accurate in how it interprets your REM sleep quality?
Meet the experts: Beth Malow, M.D., a neurologist and chief of the Division of Sleep Disorders at Vanderbilt Health; Praveen Rudraraju, M.D., medical director of the Center for Sleep Medicine at Northwell’s Northern Westchester and Phelps hospitals; Alex Dimitriu, M.D., psychiatrist and sleep medicine physician, and founder of Menlo Park Psychiatry & Sleep Medicine
Here’s what sleep medicine specialists want you to know about this phase of sleep, plus what happens if you don’t get enough.
What is REM sleep?
Sleep is divided into two main phases: rapid eye movement (REM) sleep and non-REM (NREM) sleep, according to the Cleveland Clinic.
There are three non-REM stages, broken down by numbers. When you fall asleep, you usually enter non-REM stage 1, and then cycle between non-REM stages 2 and 3. After that, you enter REM sleep (which is where you dream), per the Cleveland Clinic.
After that, you begin a new sleep cycle, going back to stage 1 or 2 and cycling through the stages again. Most people go through four or five cycles a night if they get a full night’s rest.
“REM sleep is when we consolidate our memories and learning—think of it as taking what happens during the day and putting it into long-term storage,” says Beth Malow, M.D., a neurologist and chief of the Division of Sleep Disorders at Vanderbilt Health.
The name comes from how your eyes move behind your eyelids while you’re dreaming, per the Cleveland Clinic. During this time, your brain activity is similar to what it is when you’re awake. A lot happens during this period of rest, including nightmares and vivid dreams (which may lead you on a quest to figure out what your dreams mean).
“REM is also important as it improves our creativity and problem-solving abilities,” says Praveen Rudraraju, M.D., medical director of the Center for Sleep Medicine at Northwell’s Northern Westchester and Phelps hospitals.
How much REM sleep do I need?
REM sleep usually makes up about 25% of your total sleep time, Dr. Rudraraju says. However, each REM cycle lasts for different periods, with the first lasting around 10 minutes and each subsequent REM sleep lasting longer than the one before. Longer REM cycles may last up to an hour, based on research.
So, if you snooze for the recommended seven-plus hours a night, that means that around 105 minutes of your sleep (or less than two hours) will be spent in REM.
While you can’t dictate exactly how much REM sleep you’ll get each night, research suggests that stress and sleep disorders may decrease the amount of time you spend in this sleep stage.
How much deep and light sleep do I need?
Again, your sleep is divided into stages and cycles, and the amount of time you spend in each depends on your total amount of sleep for the night.
Deep sleep is stage 3 non-REM, which is the deepest phase of non-REM sleep, while light sleep is the initial non-REM phases of sleep, or stages 1 and 2. “Deep sleep—or slow wave sleep—is also essential, and happens more in the first half of the night,” says Alex Dimitriu, M.D., psychiatrist and sleep medicine physician, and founder of Menlo Park Psychiatry & Sleep Medicine. “The body is maximally resting during this time, and the mind is cleaning up toxins accumulated during the day.”
While REM sleep makes up about 25% of your total sleep, the rest of your sleep is divided this way, per sleep medicine doctors:
- Deep sleep: 15% to 25% of sleep
- Light sleep: about 55% of sleep
The amount of time you spend in deep sleep seems to decrease as you get older, Dr. Rudraraju says.
What happens if I don’t get enough sleep?
There’s a lot that may happen if you don’t get enough sleep.
“Not getting enough sleep can affect our mood, ability to process information, and even lead to health consequences like heart attacks and strokes through increased inflammation,” Dr. Malow says.
It may also raise the risk of weight gain and elevated blood pressure, Dr. Rudraraju says. “Chronic sleep deprivation also increases mood disorders like depression and anxiety,” he adds.
The amount of time you spend in REM sleep in particular seems to have an impact on your broader health. Research has found that people with a lower percentage of REM sleep during their sleep cycle had a higher risk of early death compared to those with 15% or more of their sleep being in REM.
“In my practice, getting people to sleep well is often as important or more important than anything else I do,” Dr. Dimitriu says.
The bottom line
You can’t determine exactly how much time you’ll spend in REM sleep each night, but following good sleep hygiene, trying to minimize stress, and getting the recommended seven-plus hours of sleep each night should help support this stage of sleep.
If you’re struggling to fall asleep or stay asleep at night, talk to a healthcare provider. They should be able to do a sleep test to see what’s happening overnight, and suggest next steps from there.
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