Rapid eye movement (REM) sleep is a stage of sleep characterized by rapid eye movements, low muscle tone throughout the body, and the tendency of the sleeper to dream intensely.
Sleep cycles through REM and NREM (non-rapid eye movement) stages about every 90 minutes, with more REM sleep occurring later in the night as morning approaches.
Because dreams occur during REM sleep, it is sometimes called paradoxical sleep because the sleeper appears to be both deeply asleep and fully conscious.
What is REM sleep?
REM sleep is the fourth stage of the sleep cycle, which occurs about 90 minutes after you fall asleep. It is also known as paradoxical sleep because it reverses some of the brain activity and muscle paralysis that occurs during non-REM (NREM) sleep stages.
During REM, your brain becomes active again and changes in heart rate and breathing patterns occur. Your eyes move rapidly under closed lids, and you may feel like you're dreaming, even if you don't necessarily remember a dream later.
How long does REM sleep last?
You might be surprised to learn that REM sleep only makes up about 20% of total sleep time. You will enter REM sleep after being in non-REM sleep, and the two phases alternate throughout each night.
The first phase of REM lasts about 10 minutes, while the second lasts around 20 minutes.
What happens in the brain during REM sleep?
In REM sleep, brain activity is similar to that during waking and dreaming. This is why during REM sleep you can have experiences that seem so real and vivid in your mind. This also explains why dreams can be so intense or emotional – because of the increased brain activity associated with REM sleep.
Is dreaming the same as REM sleep?
Not. Dreaming is a form of REM sleep, but it is not the only type of REM sleep.
REM sleep is a cycle of a series of stages that make up a complete sleep cycle, which can last anywhere from 90 minutes to 2 hours 40 minutes, depending on age and other factors.
During this stage, also known as paradoxical sleep, because your eyes move back and forth under closed lids while you remain mostly still, muscles relax except those needed for breathing.
Your heart rate increases slightly as your brain waves speed up from slow-wave activity to what are called beta waves—those associated with an awake mind—and then down again to delta waves, characteristic of deep sleep.
Is everyone dreaming?
Yes, everyone dreams. You don't have to be a child or an animal for your mind to wander into the dark theater of sleep and put on a little show. Although there is some variation in the types of dreams that people have, almost all people experience REM sleep at least once during the night.
Dreams can be anything from images of flying through space to strange visions of talking cats wearing hats. These dreams may seem completely real while they are happening, but when you wake up from them the next morning, they often turn into mere fragments that quickly slip from your memory.
How do we know if we are in REM sleep?
The rapid eye movements and muscle paralysis characteristic of REM sleep can be detected using a device called an electroencephalogram (EEG). An EEG records brain waves using electrodes attached to the scalp.
A pattern of intermittent bursts of rapid electrical activity, known as complex polyspike waves or PGO waves, indicates that you have entered a period of REM sleep.
How do you know you are in REM sleep? Can REM sleep be skipped?
REM sleep is a phase of sleep in which the brain is active and the body is paralyzed. During this phase, you can dream.
What are some typical signs that indicate you are dreaming?
- Lucid dreams, where you know it's a dream and you can control things in it.*
- Dreams in which the eyes move rapidly back and forth.
- Strange sensations such as floating or flying.
- Confused feelings due to the combination of being awake and dreaming.
- Unusual smells and sounds that occur only during sleep (do not occur when you are awake).
Can you extend the duration of REM sleep?
No, it is not possible to prolong REM sleep. The body naturally enters this special phase at a certain time of the night and then goes through several cycles of altered states before waking up fully rested. However, there are factors that can affect how long you spend in REM sleep:
- Age: Children spend more time than adults sleeping and also tend to have more frequent periods of REM sleep. As you age, your body needs less rest in general; therefore, REM periods also become shorter.
- Stress Level: Increased stress levels can interfere with your ability to enter deep or slow wave phases (including stage 2). This means that even if you have enough total hours per night and all other conditions are ideal for good quality sleep, stress could still cause you problems falling asleep quickly or staying asleep long enough for all 5 stages of non-REM sleep!
REM sleep is one of the 5 stages of normal and healthy sleep.
REM sleep is one of the 5 stages of normal and healthy sleep. During this stage, you may experience some or all of the following:
- Rapid eye movement (REM)
- Muscle paralysis (you are not able to move)
- Fast heart rate
- Increase in blood pressure
If you feel that your REM sleep is inadequate, try implementing some of these tips into your routine: making sure you get a good night's rest every night, spending less time on screens before bed (or at least reducing the brightness), eating healthy foods , rich in nutrients like magnesium and potassium (like spinach), getting some exercise during the day like walking or biking instead of driving all day.
