During sleep, our brain goes through 5 different stages. One of these stages is REM sleep – rapid eye movement. During this phase, the eyes move rapidly in different directions. The other 4 stages are considered non-REM. People enter REM within the first 90 minutes of falling asleep, and it repeats several times during the night. The percentage of people who experience REM sleep cycles is 20-25% for adults, and 50% for children.
What is REM sleep?
The sleep cycle usually starts with non-REM sleep, before reaching the REM stage. The first phase of REM sleep usually lasts 10 minutes, then each phase lasts longer. The last phase of REM sleep can last up to an hour.
During REM sleep, the body and brain go through several changes, such as:
– Rapid eye movements
– Rapid, irregular breathing
– Increased heart rate
– Changes in body temperature
– Increased blood pressure
– Brain activity similar to that in the conscious phase
– Sexual arousal in both men and women
– Facial and leg spasms
Most people experience paralysis of the muscles (legs and hands), while the brain is very active and produces very intense dreams. This stage of sleep is sometimes called paradoxical sleep.
Before entering the REM phase, the body goes through each phase of non-REM sleep. Each phase lasts between 5 and 15 minutes.
The first phase: the thin line between being awake and falling asleep, called the light sleep phase.
Second phase: characterised by slightly deeper sleep. Body temperature drops and heart rate slows down.
The third and fourth phase: a deep stage of sleep, called slow wave sleep or delta sleep. Muscles relax, the blood supply in the muscles increases, tissue repairs itself, hormones are released and energy reserves are replenished.
As people get older, they experience less and less non-REM sleep. People under the age of 30 typically experience 2 hours of non-REM sleep, while older people only 30 minutes.
Improves memory and efficient learning. Researchers say that people who cannot enter REM sleep have difficulty remembering what they have learned before falling asleep. A study on rats shows that the absence of four days of REM sleep affects the proliferation of cells in the part of the brain that contributes to long-term memory.
Develops the central nervous system. REM sleep is especially important in brain development in children. Some studies indicate that this stage is responsible for the stimulation needed in the development of neurological connections.
Consequences of REM sleep deprivation
Lack of REM sleep has often been associated with:
Reduced coping skills. Some studies indicate that animals that have been deprived of REM sleep have experienced abnormalities in coping and defensive mechanisms in threatening situations.
Migraines. Insufficient REM sleep deprivation can lead to migraine headaches.
Weight gain. A study at the University of Pittsburgh found that short REM sleep cycles led to weight gain in children and adolescents.
While drinking alcohol helps some people fall asleep more easily, researchers say it reduces REM sleep. The more alcohol consumed before sleep, the more REM sleep is affected.
In 2013, 27 studies were done on the association between alcohol and sleep. These showed that night-time sleep decreased after moderate or heavy alcohol consumption. Alcohol also affects sleep in other ways; it can contribute to apnea, snoring, and frequent bathroom breaks. It also disrupts the circadian rhythm, that internal clock that regulates sleep and wake time.
REM sleep behavior disorder
This is considered a condition that many people suffer from, and is manifested by the absence of muscle paralysis that usually occurs during REM sleep. This gives rise to very intense dreams, in which affected people may kick or shake their arms. The onset of REM sleep disorder occurs gradually, with symptoms worsening over time.
It is caused by non-functioning nerve pathways in the brain. Risk factors in their development occur in:
– Male individuals
– People over the age of 50
– Taking medication, including certain antidepressants
– Completion of treatment with certain drugs or alcohol.
– Neurodegenerative disorders, such as Parkinson’s disease or dementia with Lewy bodies.
– Narcolepsy, a sleep disorder characterized by hallucinations and excessive daytime sleepiness.
Treatment for REM sleep disorder includes appropriate medication and changing the sleep environment for the safety of the affected person and sleep partner.
How to improve REM sleep
There are countless ways to improve both REM and non-REM sleep so that sleep during the night is effective. The following tips can improve REM sleep:
- Establish a sleep routine. By sticking to the same sleep schedule every night, your body and mind are prepared for sleep. It can help maximize the hours of sleep you get, and the possible phase increases experienced during REM sleep.
- Reduce frequent waking throughout the night. Noise, high temperatures and bright light can disrupt sleep. For optimal sleeping conditions, turn off phones and other sources of noise, and reduce light in the room. Keep the room temperature between 15 and 19 degrees.
- Get enough sleep. A healthy adult needs between 7 and 9 hours of sleep. Less sleep reduces the experienced phases of REM sleep.
- Remedy medical conditions. Certain medical conditions, such as apnoea, can affect sleep quality and impact on REM sleep.
- Avoid drinking alcohol before sleep. It is recommended to avoid it a few hours before bedtime, as moderate or heavy alcohol consumption reduces the number of phases experienced during REM sleep, and any amount of alcohol can delay the first phase of REM sleep.