What is REM Rebound Sleep?

If you find that you are falling into REM sleep rather quickly or spending and excessive amount of time there, you are probably experiencing REM rebound.

By Loren Bullock

Have you ever had a night where it seemed that you dreamt more than usual? You were probably experiencing a sleep stage increase called REM rebound sleep. But what is REM rebound sleep exactly, and what is the cause? We’ll answer both of these questions and more as we explore this interesting sleep phenomena.

But before we jump into REM rebound sleep, let’s talk about regular ole REM sleep.

REM Sleep

Three are four stages in the sleep cycle: the first three are NREM sleep and the last is REM sleep (or rapid eye movement sleep). The NREM stages slowly coax you into a deep sleep before REM begins.

  • N1 is the light sleeping stage where you can be easily woken, but just start to drift off.
  • N2 is where your heart rate slows, your eyes cease their movements, and your body temperature drops.
  • N3 is the deep sleep stage. During N3, your body physically repairs itself, from from the muscles and tissues, to immune function.

As you enter REM, about 70-90 minutes after you fall asleep, your brain becomes more active. This is the sleep stage where you begin to store memories, solve our waking problems, and some theorize that it helps improve mood.

REM rebound sleep is characterized as an increased amount of REM sleep throughout the night when compared to normal REM lengths and frequencies. REM makes up about 20% of the night’s sleep stages, but those experiencing REM rebound see about a 7% increase. So, why does REM rebound occur?

Cause of REM Rebound

Simply put, REM rebound is caused by sleep deprivation. When you miss those precious hours of sleep, your brain misses out on the amount of sleep cycles it needs—including REM sleep. Over time, you start to build up to REM sleep debt. So, when you finally lie down to rest, your body tries to make up for the lost REM sleep by not only making this stage longer, but more frequent.

With REM rebound, the first REM sleep period occurs soon after falling asleep rather than 70 minutes after. Every REM cycle after that is much longer than it would normally be. The dreams during these cycles are usually very vivid and intense. Sometimes they are so intense that dreamers are awoken suddenly, possibly to sleep paralysis.

The REM Rebound Effect shows scientists and sleep researchers how important REM sleep is to the body and the brain.

REM Rebound and Alcohol

When you consume alcohol, it shortens your REM cycle during the first cycle at night. Then, as your body metabolizes it, you experience slight withdrawal symptoms. These include

  • Sleep disruption and frequent awakenings (which can lead to REM rebound)
  • REM rebound
  • Nightmares
  • Insomnia (which can lead to REM rebound)

Though some use alcohol to fall asleep, it leads to a poor, less restorative night’s sleep.

REM Rebound and Sleep Apnea

Studies have shown that REM rebound is prevalent in people with sleep apnea—especially as they use a CPAP. A CPAP (continuous positive airway pressure) is a machine to help sleep apnea patients breathe as they sleep.

In one 2017 study in particular, the results showed a 57% increase in REM sleep duration while patients used the CPAP.

Is REM Rebound Dangerous?

It is important to remember that REM rebound is something everyone has probably experienced at one point or another; it is our brain’s way of making up for lost sleep. Researchers say that REM rebound sleep is not dangerous or harmful. In fact, sleep scientists are more puzzled and interested in REM rebound than anything.

However, there is such a thing as too much REM sleep. People who suffer from Excessive REM sleep can feel tired and groggy the next day. This could be a sign of any number of sleep disorders, depression, or a bigger health issue. If you find that you are in REM sleep majority of the night or that your sleep duration is more than 10 hours, it may be time to contact your doctor.

If you want to know exactly how much time you are spending in REM, there are ways to obtain this information. The easiest way is by using a sleep tracker. A sleep tracker collects data through movement, heart rate, and breath. They take these biometrics and turn them into easily digestible data (such as how long you spend in each sleep stage).


REM rebound sleep is a deviation from your body’s natural sleep cycle. When you deprive yourself of sufficient REM sleep (either through sleep deprivation, substance withdrawal, or sleep apnea) your brain with make up for it by promoting extra and longer REM cycles. With your REM increased, you will experience more dreams that are vivid or nightmarish. Your body may wake itself up before the REM cycle is finished, causing sleep paralysis. Despite these side effects, REM rebound is completely normal and nothing to worry about.

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