During sleep, the brain moves through four different stages. One of these stages is rapid eye movement (REM) sleep. During this phase, the eyes move rapidly in various directions.
People typically enter REM sleep within the first
Most dreams occur during REM sleep. This is a stage that may play a role in learning, memory, and mood.
This article covers REM sleep in more detail, including its stages, functions, and more.
REM sleep typically starts within
During REM sleep, the body and brain go through several changes, including:
- rapid movements of the eyes
- fast and irregular breathing
- increased heart rate (to near waking levels)
- changes in body temperature
- increased blood pressure
- brain activity (similar to waking levels)
- increased oxygen consumption by the brain
- sexual arousal
- twitching of the face and limbs
Most people experience a state of temporary paralysis as the brain signals the spinal cord to cease the movement of the arms and legs.
This lack of muscle activity is known as atonia, and it may be a protective mechanism to prevent injury that may result from “acting out” our dreams.
During REM sleep, people may experience vivid dreams due to the increase in brain activity.
Before entering the REM sleep phase, the body goes through each of the stages of non-REM sleep. The sections below look at each of these in more detail.
Stage 1 non-REM sleep
A person in this stage is between being awake and asleep or is in a state of very light sleep.
Stage 2 non-REM sleep
A slightly deeper sleep characterizes this stage. Body temperature drops, and heart rate slows down. Most people spend
Stages 3 non-REM sleep
Stage 3 non-REM sleep is a state of deep and restorative sleep known as slow-wave sleep or delta sleep. The muscles relax, the supply of blood to the muscles increases, and the body repairs and grows tissue.
People enter the REM sleep phase following the above stages. This is the stage of sleep during which most people dream, though this may also happen in non-REM sleep.
REM sleep may benefit
Learning and memory
The brain processes information and consolidates memories during sleep. As a result, sleep deprivation can
According to some studies, even short periods of daytime sleep can help a person learn muscle patterns (motor memory) and commit them to memory.
Central nervous system development
REM sleep may be essential for brain development in infants. Some research indicates that this sleep stage is responsible for the neural stimulation necessary for mature brain structure developments.
These findings may help explain why infants require higher levels of REM sleep, with the number of minutes of REM sleep falling as people age.
Consequences of a lack of REM sleep
Some studies link a lack of REM sleep to:
- Reduced coping skills:
Some researchsuggests that a lack of REM sleep may reduce a person’s ability to differentiate between threatening and non-threatening stimuli and respond accordingly.
- Migraine: Fragmented sleep may
increase a person’s riskof experiencing migraine in the immediately following days. However, low sleep duration and quality did have an effect on migraine rate.
- Obesity: Some studies associate the quantity and quality of sleep with an
increased chanceof obesity.
Drinking alcohol before sleep can disrupt a person’s sleep cycle and sleep quality. Research is conflicting on how exactly alcohol affects REM sleep.
Alcohol affects sleep in other ways, too. For example, it contributes to sleep apnea and snoring, causes an increase in bathroom visits, and interrupts the body’s circadian rhythm, which is the internal clock that regulates sleep and wake times.
Some people experience REM sleep behavior disorder (RBD). This is a condition wherein the muscle paralysis a person usually experiences during REM sleep does not occur. It causes the person to act out vivid dreams. For example, they may kick, yell, or flail their arms.
The onset of RBD tends to be gradual, with symptoms worsening over time.
RBD results from malfunctioning nerve pathways in the brain. Some risk factors for its development include:
- being male
- being over 50 years old
- taking antidepressants
- experiencing withdrawal from drugs or alcohol
- having a neurodegenerative condition, such as Parkinson’s disease
- having narcolepsy, which is a sleep disorder characterized by excessive daytime sleepiness and hallucinations
Treatment for RBD includes medication and changing the sleep environment to increase safety for the person with the condition and their sleeping partner.
There are several ways to enhance both REM and non-REM sleep to reap the benefits of high quality sleep. The following tips may help improve REM sleep.
Get enough sleep
A healthy adult requires
Address medical conditions
Certain medical conditions, such as sleep apnea, can affect sleep quality and impact REM sleep. Addressing these conditions may help improve the overall quality of sleep.
Avoid alcohol before bedtime
As moderate-to-high levels of alcohol intake before bed can reduce the number of REM sleep phases and delay entering the first REM phase, it is advisable to avoid alcohol consumption in the hours immediately before bed.
Following the same bedtime routine each day prepares the body and mind for sleep. Having a regular bedtime routine may help maximize the amount of time asleep, potentially increasing the number of REM sleep phases a person experiences.
- going to bed and waking up at consistent times
- removing electronic devices from the bedroom
- increasing physical activity in the day
- keeping the bedroom cool, dark, and quiet
- avoiding large meals and caffeine before bed
REM sleep is the stage in which most people vividly dream. These periods of sleep typically start around 90 minutes after someone falls asleep and cycle every subsequent 90 minutes.
REM sleep is important to the consolidation of information and the development of memories. Research has linked disruptions in REM sleep with an increased chance of obesity and risk of migraine.
Developing good sleep habits and having a consistent pre-sleep routine can help people improve the quality of their REM sleep and the quality of their overall rest time.