Characteristics of REM Sleep

Did you know that REM sleep is involved in processes such as memory consolidation and learning? Continue reading to learn more about the process.
Characteristics of REM Sleep
Bernardo Peña

Written and verified by the psychologist Bernardo Peña.

Last update: 11 June, 2022

REM sleep (rapid eye movement) comprises 25% of the sleeping cycle. Researchers estimate it occurs between 70 and 90 minutes after we fall asleep. Furthermore, it occurs several times during the night, as the cycles repeat.

How does it happen? What are its characteristics? Today’s article will answer these questions. In addition, we’ll detail its association with cognitive processes and memory.

REM sleep

Rapid eye movement is one of the two stages of sleep and is present in any mammals, birds, and other animals that have a pineal gland.

The main characteristics of REM sleep are:

  • Rapid random eye movements
  • Reduced muscle tone throughout the body
  • Vivid dreams
  • Rapid low voltage brain waves

The brain stem starts all these chemical and electrical activities. In addition, it seems to indirectly intervene in the transmission of acetylcholine, which limits the production of histamine, serotonin, and noradrenaline.

Ponto-Geniculo-Occipital waves (PGO) originate in the brain stem and happen before and after REM sleep. They reach their greatest amplitude in the visual associative cortex (which is why we see things when we dream).

Moreover, the brain energy unleashed during this phase, e.g. from glucose and oxygen metabolism, exceeds what we use while we’re awake.

A sleeping man.
REM sleep corresponds to 25% of the sleep cycle. Moreover, it occurs several times during the rest period.

Find out how Irregular Sleep Can Increase the Risk of Cardiovascular Problems

Characteristics of REM sleep

REM sleep is a stage of light sleep. In fact, those who wake up during this stage remember perfectly what they were dreaming and wake up alert. They feel well-rested. In addition, erections and irregular heart and respiratory rates are common during this stage.

This is a characteristic stage of sleep. Thus, the other stages are simply referred to as non-REM, slow-wave, or deep sleep.

It’s common to go through four or five stages of REM sleep during the night. This is why it’s also common to wake up for a few moments after this phase is over. Nevertheless, it’s easy to go back to sleep afterward.

It’s also during this phase that the brain releases the MAO enzyme. It catalyzes the oxidation of certain monoamine neurotransmitters and thus inhibits movement. We would move during sleep like we do when we’re awake.

Some people wake up in the middle of REM sleep, with a distressing feeling of paralysis and the presence of hallucinations. We refer to it as sleep paralysis.

Check out these Five Tips to Prevent Sleep Paralysis

We must be grateful about this sleeping stage


  • Neuronal activity reactivates and strengthens during sleep
  • It boosts the activity of the hippocampus, neocortex, and thalamus (strengthens memory and learning consolidation)
  • Physical and intellectual activity enhances REM sleep which, in turn, reinforces these learning processes
  • It matures the neural connection in newborns and infants, which is why they sleep so much
The waves of a resting brain.
Neuronal activity reactivates during sleep and fulfills functions that determine learning and memory.

REM sleep and memory

Some scientific studies reveal that REM sleep plays a role in memory consolidation. Specifically, researchers drew the following conclusions:

  • Sleep deprivation has a negative impact on memory consolidation
  • Maintaining adequate sleep hygiene has a positive effect on learning and memory consolidation
  • REM sleep, in particular, is linked to memory and learning potential

According to these data, one can conclude that both sleeping and dreaming have a positive effect on our memory. Thus, it has significant implications when we study or work. This is why it makes sense to have a good night’s sleep. It helps us remember what we learned during the day.

However, other scientists point out that we still have little data and need more research to be able to make inferences such as those presented in the previous sections.

Sleep is important for the organism

In short, sleep plays a decisive role in overall physical and cognitive health. Hence, we must get enough sleep to rest and dream if we want to consolidate learning and improve memory while repairing the body’s cells. Our body will take care of the rest.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • De Riquer, A. I. (2013). El trastorno de conducta del sueño rem. Revista Médica Clínica Las Condes24(3), 463-472.
  • Reinoso-Suárez, F. (2005). Neurobiología del sueño. Revista de Medicina de la Universidad de Navarra, 10-17.
  • Velayos, J. L., Moleres, F. J., Irujo, A. M., Yllanes, D., & Paternain, B. (2007). Bases anatómicas del sueño. In Anales del sistema sanitario de Navarra (Vol. 30, pp. 7-17).

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.