Today, a large majority of the population knows or has heard on some occasion about the concept of REM phase or REM sleep We know that it is part of our sleep and that, at the very least, it presents some differences when it comes to the rest of sleep, non-REM.
Many people do not know what makes this dream such a necessary element for us. That is why in this article we are going to make a brief comment regarding what REM sleep is, and its peculiarities.
Sleep is an essential need for human beings and for most living beings. Our body is a structure that continuously consumes energy, requiring the elements of our rest “machinery” to be able to function correctly.
Sleep is essential. However, sleep is not something uniform that appears suddenly. In fact, during sleep, various cycles composed of different phases occur, in which different functions are altered and in which our brain reduces or increases certain types of bioelectrical activity Specifically, we usually have between 4 and 9 of these cycles, each of them divided into five phases. These phases usually follow a certain order.
First of all, in phase 1 we find ourselves in a phase of drowsiness, in which our consciousness is gradually reduced even though we can wake up with the slightest stimulation. Our brain mainly registers alpha-type waves, which are common in states of relaxation even when we are awake.
Subsequently, and if nothing interrupts it, we enter a second phase, in which eye movements are completely reduced and there is a marked decrease in muscle tone. We are increasingly relaxed and disconnected from our surroundings. If we observe the functioning of the brain at the level of waves with an electroencephalogram, we observe how theta waves prevail, with the peculiarity that oscillations appear in brain activity. in the form of K complexes and sleep spindles
After these phases, both of which are light sleep, we would enter phases 3 and 4 of sleep, known as deep sleep. These are the phases in which a true rest of the body occurs. Physical activity is practically non-existent for most people, although there is an increase in muscle tone Night terrors and other parasomnias such as sleepwalking occur during these phases of sleep. The recording of brain waves would show a general prevalence of delta waves.
These phases correspond entirely to non-REM sleep. But after them, we can still find one more phase, the REM or REM phase.
The REM or REM phase
The REM phase (REM being the acronym for Rapid Eye Movement) or REM (Rapid Eye Movements), is one of the most important phases of sleep. It is characterized by the presence of high brain activity, which can be visible when performing tasks. rapid and constant eye movements
It is considered desynchronized sleep. Brain activity is similar to what we would have when awake or in the phases of drowsiness, there are abundant theta waves with saw teeth (the latter especially characteristic of the parietal areas of the brain) and beta. The body remains completely immobile and paralyzed, with complete disappearance of muscle tone except in the eyes and diaphragm.
It is in the REM phase of sleep that dreams and nightmares appear, as well as the ability to remember them. There is also an increase in physiological activation (despite muscle atony), increasing blood pressure, heart and respiratory rate and the appearance of erections being common. As the cycles occur, the amount of REM sleep increases.
Main function of this stage of sleep
The functions of this type of dream are not clearly defined. However, it is considered that during REM sleep we reorganize our mental contents, fixing new memories and integrating them into memory at the same time we discard those information or memories considered irrelevant. Thus, this type of dream converts the experience into a memory stored in long-term memory.
Likewise, it is during these phases that the highest level of brain development occurs, being essential for its maturation, especially during the growth stage. It is considered desynchronized sleep.
This It is not only important on a cognitive level, but also with regard to sensory processing, as studies such as those by Marcos Frank at the National Institute of Health of the United States seem to indicate, by allowing, for example, the ERK protein (a protein that is only activated in this phase of sleep). ) finish fixing the changes in the visual cortex and adjusting the connections that allow the development of visual perception. The same goes for other skills.
Evolution throughout the life cycle
Throughout life our biorhythms and our sleep cycles vary greatly We don’t sleep the same during our first year of life as we did at thirty, and even less than at eighty years old.
Newborns, for example, spend a large part of the day sleeping, spending around 50% of this time in the REM phase. From the fourth month onwards this percentage is reduced to 40% and begins to be preceded by non-REM sleep. As the child grows, the time spent awake increases and the amount of sleep decreases. At the age of approximately six years, sleep patterns and cycles stabilize, resembling adult sleep.
During adulthood the approximate proportion of REM sleep is 20%, with the rest being non-REM sleep. With age, total sleep time reduces and becomes fragmented, especially when we reach old age, with a large number of nocturnal awakenings The amount of sleep is dramatically reduced, including REM sleep. Despite this, a lower latency of REM sleep is observed (it takes less time to appear).
