What is REM sleep? Human sleep phases

Good rest is one of the main components of human health. For the formation, development, normal functioning of the body, ideal conditions are created during sleep. Only during this period useful hormones are produced, amino acids are synthesized. There is also improvement, systematization of brain activity, unloading of the nervous system.

To understand the ongoing processes, one should study what slow and fast sleep is, what are the differences between these structural units and determine their importance for people. These parameters are well compared according to the indications from the comparative tables.

The psychophysical processes that take place during sleep divide it into phases. At this time, there is a different activity of the brain, regeneration of certain organs and systems takes place.

REM sleep and slow sleep have a certain relationship. It changes from one cycle to the next. The constant interruption of one of the components has negative consequences.

Phase components of sleep and their sequence

Sleep is a certain structure, it includes several cycles that appear 4-5 times a night. Each one is approximately 1.5 hours long. This form contains the phases of non-REM and REM sleep.

An adult's rest begins with a nap, which is the initial structural unit of the slow period. Then three more components pass in turn. Then there is a short interval. The duration changes every cycle.

Features of slow sleep

The slow period lasts three-quarters of the duration of the rest. After falling asleep, it has the greatest length, gradually decreasing in the morning.

For a long rest, 4-5 periods are included in the cycles, this is the optimal value. It starts the process of falling asleep. In the third phase, bouts of sleepwalking may occur.

Structure

This phase is structured by periods. All of them are of great importance for a person. Each has its own characteristics, features, functions change in the process.

• nap;
• sleep spindles;
• delta sleep;
• deep delta sleep.

The first period is characterized by slow eye movement, a decrease in temperature occurs, the pulse becomes less frequent, stabilization of nervous activity occurs. It is at this moment that the solution to the problem that appeared during the day can come, the missing link in the semantic chain will be filled. Waking up is very easy.

In the second interval, consciousness begins to turn off, a person sinks deeper into drowsiness. The pulse is rare, muscle relaxation occurs.

During the third stage, the heart begins to contract more often, more superficial respiratory oscillations occur. The blood flow to the tissues is activated, the movement of the eyes is very slow.

The last period is characterized by the greatest immersion. At such a moment, it is very difficult for people to wake up, they get up not rested, it is hard to get involved in the environment, dreams are not stored in memory. All body functions are significantly slowed down.

signs

To understand that a person is in a phase of slow sleep, it will turn out if we compare the characteristic indicators: breathing, which becomes rare, shallow, often arrhythmic, the movement of the eyeballs first slows down, then completely disappears.

The heart rate slows down, the body temperature drops. By this period, the muscles relax, the limbs do not move, and there is no physical activity.

Meaning

When you are in a slow sleep, the restoration of internal organs occurs. During this time, growth hormone is released, this is especially important for children. They develop, improve all systems for such a period.

It's important to know! During this period, the substances necessary for the normal functioning of the body accumulate, amino acids are synthesized. This type of sleep is responsible for physiological rest.

REM sleep contradictions

REM sleep is also called paradoxical because of the inconsistencies between its various manifestations and internal processes. During such a period of rest, brain activity is very active, it can be even higher than during wakefulness, but a person at this time is in the process of dozing.

Muscle tone is significantly reduced, but the stage is characterized by the movement of the eyeballs, twitching of the limbs. If such a rest for some reason takes a long time, upon awakening there is a feeling of weakness, fragments of dreams are spinning in the head.

Manifestations

The fact that a person is in REM sleep can be seen without the help of devices. There are a number of specific manifestations. These include:

Body temperature rises, heart rate increases. The brain starts active. At this interval of rest, a combination occurs, a comparison of genetic information with the acquired one.

The value of the fast phase

During the period of fast rest, the nervous system is activated. All acquired knowledge, information, relationships, actions are processed and analyzed. Serotonin, the happy hormone, is produced.

During this period, the formation of the most important mental functions in children takes place. Insufficient duration of such rest can mean the imminent appearance of problems with consciousness. Programs for the future behavior of a person are created, answers are formulated to questions that cannot be found while awake.

dreams

Dreams that come to a person in this phase are the most vivid and memorable. They are colored emotionally, dynamically. External stimuli can be intricately woven into the plot of the vision.

Visions are transformed into different symbols, images, everyday reality. In the paradoxical phase, usually a person realizes that events are not happening in reality.

Awakening in different phases: differences

The structure of sleep is heterogeneous. All phases are distinguished by different brain activity, psychophysical activity, regeneration of certain human systems.

It's important to know! The incompleteness of the processes causes a complex transition to wakefulness in non-REM sleep. With a quick rise, it is easy, the beginning of vigorous activity occurs without problems. But the constant interruption of rest in this phase has a negative effect on the psyche.

Table: comparative characteristics of sleep phases

The parameters characterizing fast and slow sleep are shown in a comparative table. This is the main data that helps to recognize the rest period. From one cycle to the next, the duration of the first becomes shorter, the paradoxical lengthens.

Sleep research: interesting facts

The paradox of time perception is often encountered in relation to sleep. There are times when it seems only closed his eyes, and several hours have already passed. The opposite also happens: it seems that you slept all night, and 30 minutes have passed.

It has been proven that the brain analyzes sounds that are heard, sorts them, and can weave them into a dream. At the same time, in some phases, people can wake up if they are called by name in a whisper. The greater the biological age of a person, the shorter the duration of the paradoxical stage. In infants, it exceeds the slow one.

A person spends a third of his life in sleep. If you sleep less than a quarter of the day for two weeks, the state of the body will correspond to being intoxicated. Memory will worsen, concentration of attention, reaction will suffer, there will be a problem with coordination. But many geniuses over a long period of time practiced polyphasic rest, the total duration of which was no more than half the norm. At the same time, they felt cheerful, their efficiency improved, discoveries were made.

Dreams are seen by absolutely all people, but almost all of them are forgotten. Animals also dream. Not so long ago, most of humanity saw black and white dreams, and now 85% of men and women are viewing vivid stories. The explanation for this is the creation of color television broadcasting.

Blind people are also not deprived of dreams. If blindness is acquired, then the pictures make up what was seen earlier. With congenital absence of vision, vision consists of sounds, smells, sensations. They do not have such a phenomenon as rapidly moving eyes under the eyelids. These people are much more likely to have nightmares.

The longest period of wakefulness of a healthy person was a time period of 11 days that an American schoolboy did not sleep. After a head injury and brain damage, a soldier from Hungary did not fall into a nap for 40 years. At the same time, he felt cheerful, did not experience fatigue, discomfort.

It's important to know! Few girls who dream of a slim figure know the following fact. Regular lack of sleep leads to weight gain. One of the important conditions for losing weight is sufficient sleep.

Women's deep rest is often 20 minutes longer than men's, but the latter sleep more restlessly, waking up more often. The weaker sex at the same time complains more about sleep disturbances, sleeps worse. Ladies are more prone to emotionally strong visions, nightmares.

Conclusion

You can not make a choice which sleep is better fast or slow. Both of these components must be present in a person’s rest necessarily and in the correct percentage.

Article content

In a sleeping person, the body works in an unusual mode: consciousness turns off, and the moment comes for the restoration of cells and tissues. Everything happens in a certain stage called slow sleep, the value of which is very high. It is his absence or awakening in this period that provokes a broken, lethargic and sleepy state.

Human sleep pattern

Going to bed, a person does not suspect what happens in the head during a night's rest. Enjoying in the arms of Morpheus, he goes through several stages of sleep:

• slow (deep) - longer, helps to restore energy costs;
• fast (superficial) - characterized by an increase in brain activity.

The stages are constantly changing. The phase of non-REM sleep is accompanied by fast sleep - together they make up one complete cycle. Its duration is about 1.5-2 hours. For the normal functioning of body systems and quality rest, a person needs to go through 4-6 cycles per night. Moreover, they must be completed before 04:00 am, as this is the optimal time to replenish energy. Then the dream continues, but the fast stage becomes the main one. It is noteworthy that the slow phase is the longest at the very beginning of the night's rest, while it decreases in the morning. The surface, on the contrary, is short in the first cycle and gradually increases towards awakening.

Night rest is a natural component of the life of every person, both for an adult and for a child. When people sleep well, they not only elevate their mood levels and feel better, but they also show a significant increase in mental and physical performance. However, the functions of a night's sleep do not end only at rest. It is believed that it is during the night that all the information received during the day passes into long-term memory. Night rest can be divided into two phases: non-REM sleep and REM sleep. Especially relevant for a person is deep sleep, which is part of the slow phase of nighttime rest, since it is during this period of time that a number of important processes occur in the brain, and a violation of this phase of slow sleep leads to a feeling of lack of sleep, irritability and other unpleasant manifestations. Understanding the importance of the deep phase of sleep allows you to develop a number of tips for normalizing it in each person.

Sleep includes a series of stages that regularly repeat throughout the night.

Night rest periods

The entire period of dreams in humans can be divided into two main phases: slow and fast. As a rule, falling asleep normally begins with a phase of slow sleep, which in its duration should significantly exceed the fast phase. Closer to the awakening process, the ratio of these phases changes.

How long do these stages last? The duration of slow-wave sleep, which has four stages, ranges from 1.5 to 2 hours. REM sleep lasts 5 to 10 minutes. It is these numbers that determine one sleep cycle in an adult. In children, the data on how long the night rest cycle should last is different from adults.

With each new repetition, the duration of the slow phase continues to decrease, while the fast phase, on the contrary, increases. In total, during a night's rest, a sleeping person goes through 4-5 such cycles.

How much does deep sleep affect a person? It is this phase of rest during the night that ensures our recovery and replenishment of physical and intellectual energy.

Features of deep sleep

When a person has a slow sleep, he successively goes through four stages, which differ from each other in the features of the picture on the electroencephalogram (EEG) and the level of consciousness.

1. In the first phase, a person notes drowsiness and half-asleep visions, from which one can easily wake up. Typically, people talk about thinking about their problems and looking for solutions.
2. The second stage is characterized by the appearance of sleep "spindles" on the electroencephalogram. The consciousness of the sleeping person is absent, however, he is easily awakened by any external influence. Sleepy "spindles" (bursts of activity) are the main difference of this stage.
3. In the third stage, sleep becomes even deeper. On the EEG, the rhythm slows down, slow delta waves of 1-4 Hz appear.
4. The slowest delta sleep is the deepest period of nightly rest, which is required for the rest of sleeping people.

The second and third stages are sometimes combined into the "delta sleep" phase. Normally, all four stages should always be. And each deeper phase must come after the previous one has passed. "Delta sleep" is especially important, since it is he who determines the sufficient depth of sleep and allows you to move on to the phase of REM sleep with dreams.

Sleep phases make up the sleep cycle

Changes in the body

The rate of deep sleep for an adult and a child is about 30% of the total night's rest. During the period of delta sleep, significant changes occur in the work of internal organs: the heart rate and respiratory rate become lower, the skeletal muscles relax. There are few involuntary movements or they are completely absent. Waking up a person is almost impossible - for this you need to call him very loudly or shake him.

According to the latest scientific data, it is in the phase of deep sleep in the tissues and cells of the body that normalization of metabolic processes and active recovery take place, allowing the internal organs and brain to be prepared for a new period of wakefulness. If you increase the ratio of REM sleep to slow sleep, then the person will feel bad, feel muscle weakness, etc.

The second most important function of the delta period is the transfer of information from short-term memory to long-term memory. This process occurs in a special structure of the brain - the hippocampus, and takes several hours in duration. With a chronic violation of night rest, people note an increase in the number of errors when checking the efficiency of memory, speed of thinking and other mental functions. In this regard, it becomes clear that it is necessary to get enough sleep and provide yourself with a good night's rest.

Deep phase duration

The average sleep duration of a person usually depends on numerous factors.

When people ask about how many hours a day you need to sleep in order to get enough sleep, this is not a completely correct question. Napoleon could say: “I sleep only 4 hours a day and feel good,” and Henry Ford could object to him, since he rested for 8-10 hours. Individual values ​​of the norm of night rest differ significantly between different people. As a rule, if a person is not limited in the recovery period at night, then on average he sleeps from 7 to 8 hours. This interval fits the rest of most people on our planet.

REM sleep lasts only 10-20% of the total night's rest, and the rest of the time the slow period continues. Interestingly, a person can independently influence how long he will sleep and how much time is needed for recovery.

Increasing delta sleep

• Each person must strictly adhere to the regime of falling asleep and waking up. This allows you to normalize the duration of the night's rest and facilitate the morning awakening.

It is very important to maintain a sleep-wake schedule.

• It is not recommended to eat before rest, as well as not to smoke, consume energy drinks, etc. It is possible to limit yourself to a light snack in the form of kefir or an apple a couple of hours before going to bed.
• In order for the deep phase to last longer, it is necessary to give the body physical activity of adequate intensity 3-4 hours before falling asleep.
• Helping you fall asleep faster and get quality sleep can be done with light music or nature sounds. For example, cricket singing for deep sleep is known to be very beneficial. This means that listening to music during the rest is recommended by doctors, however, it is very important to correctly select it.
• Before going to bed, it is best to ventilate the room well and eliminate any possible sources of noise.

Sleep disorders

Woman suffering from insomnia

What percentage of people have to deal with sleep disorders? Statistics in our country show that every fourth person experiences certain problems associated with night rest. However, differences between countries are minimal.

All violations in this area of ​​human life can be divided into three large groups:

1. Sleep problems;
2. Violations of the process of night rest;
3. Problems with well-being after waking up.

What are sleep disorders? These are temporary disorders of any phase of a night's rest, leading to disorders in various areas of the human psyche during wakefulness.

All three types of sleep disorders lead to common manifestations: lethargy, fatigue are noted during the day, and physical and mental performance decreases. A person has a bad mood, lack of motivation for activity. With a long course, depression may develop. At the same time, it is very difficult to identify the main cause of the development of such disorders, due to their large number.

Sleepiness during the day, insomnia at night

Causes of deep sleep disorders

Within one or two nights, sleep disturbances in a person may not have any serious cause and go away on their own. However, if violations persist for a long time, then there may be very serious reasons behind them.

1. Changes in the psycho-emotional sphere of a person, and, first of all, chronic stress leads to persistent sleep disturbance. As a rule, for such a psycho-emotional overstrain, there must be some kind of psycho-traumatic factor that led to a disruption in the process of falling asleep and the subsequent onset of the delta sleep phase. But sometimes it is also mental illness (depression, bipolar affective disorder, etc.).
2. Diseases of the internal organs play an important role in disturbing deep sleep, as the symptoms of diseases can prevent a person from fully resting during the night. Various pain sensations in patients with osteochondrosis, traumatic injuries cause constant awakenings in the middle of the night, bringing significant discomfort. Men may have frequent urination leading to frequent waking to go to the toilet. For these questions, it is best to consult with your doctor.

However, the most common cause of sleep problems is related to the emotional side of a person's life. It is the causes of this group that are found in most all cases of sleep problems.

Emotional disorders and night rest

Sleep and stress are linked

People with emotional disorders cannot sleep because they have increased levels of anxiety and depressive changes. But if you manage to fall asleep quickly, then the quality of sleep may not suffer, although usually the delta sleep phase in these cases is reduced or does not occur at all. Intrasomnic and postsomnic disorders may additionally appear. If we talk about major depression, then patients get up early in the morning and from the very moment of awakening they are immersed in their negative thoughts, which reach a maximum in the evening, leading to a disruption in the process of falling asleep. As a rule, deep sleep disorders occur together with other symptoms, however, in some patients, they may be the only manifestation of diseases.

There is another category of patients experiencing the opposite problem - the initial stages of slow sleep can occur during wakefulness, leading to the development of hypersomnia, when a person constantly notes high drowsiness and can fall asleep in the most inappropriate place. With the hereditary nature of this condition, a diagnosis of narcolepsy is made, requiring special therapy.

Treatment options

Identification of the causes of deep sleep disorders and determines the approach to treatment in a particular patient. If such disorders are associated with diseases of the internal organs, then it is necessary to organize appropriate treatment aimed at the complete recovery of the patient.

If problems arise as a result of depression, then a person is recommended to undergo a course of psychotherapy and use antidepressants to cope with disorders in the psycho-emotional sphere. As a rule, the use of sleeping pills is limited, due to their possible negative impact on the quality of the recovery itself at night.

Sleeping pills should only be taken as directed by a doctor.

It is recommended to take medicines to restore the quality of night rest only as prescribed by the attending physician.

Thus, the phase of deep sleep has a significant impact on the period of wakefulness of a person. In this regard, each of us needs to organize optimal conditions to ensure its adequate duration and complete recovery of the body. If any sleep disorders appear, you should always seek help from your doctor, as a full diagnostic examination allows you to detect the causes of disorders and prescribe a rational treatment that restores the duration of delta sleep and the quality of life of the patient.

For a long time it was believed that during sleep, the body simply turns off and rests. Only thanks to research into the phenomenon of sleep, it became clear that the brain and life support systems are actively functioning during sleep and doing the necessary work during its appropriate periods. Yes, it is not homogeneous and consists of certain phases of sleep, each of which has its own characteristics and serves certain purposes. Understanding the phases of sleep (or stages of sleep) will help us see how important it is to follow the recommendations in order to achieve the most effective rest on the one hand, and the active functioning of our brain and body on the other.

Sleep phases and their characteristics

What is sleep phases What do they depend on and how are they determined? First of all, it should be noted that each phase of sleep is associated with a certain type of wave of electrical activity in the brain. There are two main phases of sleep:

• REM sleep(rapid sleep stage)
• deep sleep phase(sleep stage)

Deep sleep is divided into 3 types.

Usually, sleep begins with phase 1 deep sleep. Next comes the phase of deep sleep 2, followed by the phase of deep sleep 3. And only when all three phases of deep sleep pass through, a transition to the REM phase is possible. Consider each of the phases in more detail:

Deep sleep phase 1.

From this stage of slow sleep begins our journey. Our sleep in this phase of deep sleep is easily disturbed, we are awakened by any noise or other influence. During this phase of sleep, our muscles relax, heart rate and breathing slow down. There are slight eye movements under the eyelids.

Deep sleep phase 2.

This stage of sleep is characterized by our slow wave brain waves with occasional bursts of fast wave activity. Eye movements stop. In NREM stage 2, we spend about the first half of our night.

Deep sleep phase 3.

In sleep stage 3, the speed of the waves becomes even lower and the brain begins to reproduce almost only very slow waves (Delta waves). This is a very deep stage of non-REM sleep and it is not easy to wake up during it.

REM sleep phase.

This stage of sleep wedged periodically into phases 2 and 3 throughout the night. The first appearance of the REM stage begins about an hour and a half after we fell asleep. This stage is characterized by rapid eye movements under the eyelids, intermittent, uneven breathing and heartbeat, the muscles of the arms and legs are periodically paralyzed. The phase of REM sleep is also different in that it is here that we see dreams. We spend about one-fifth of the night in REM sleep (the same amount as in deep phase 3).

The duration of a particular phase of sleep changes with age. For example, an infant spends up to 50% of all sleep time in REM sleep, while in an adult it is only 20%. In addition, the distribution of sleep phases can be influenced by both external conditions and the internal state of a person. You can’t write off the effects of medications either - this is how Prozac, quite popular in the USA, is able to prevent the full flow of the REM sleep phase. Drinking alcohol before bedtime also affects REM sleep, pushing it back in the overall cycle to a later time of occurrence.

Irregular and unregulated sleep has a negative impact on the orderly flow of all phases of sleep. The phases go astray, which means that the brain is not able to complete all the planned processes in order to maintain the healthy functioning of the whole organism.

Sleep structure

Now to the practical side. Since sleep has a cyclical structure, sleep phases are repeated throughout the night in the following order G1-G2-G3-G2-G1-B. This is one cycle. The average duration of the first cycle is somewhat shorter than the subsequent ones and ranges from 70 to 100 minutes, the second and then from 90 to 120 minutes. In many sources, you can find that the average value is taken as a cycle - 90 minutes. It is important to remember that 90 min. - this is an approximate figure, and when calculating the total sleep time (number of cycles per night), you must definitely focus on your well-being. You can read more about sleep recommendations. So the first recommendation is:

RECOMMENDATION 1: Total sleep should be a multiple of a full cycle (90 to 120 minutes)

However, our well-being, easy and pleasant awakening is connected not only with the number of hours allotted for sleep, but also with the phase in which the awakening occurs. If we follow the rule of multiples of the total sleep time per cycle (the duration of the first cycle varies from 70 to 100 minutes, the second and subsequent from 90 to 120 minutes), then we automatically comply with the conditions for awakening at the beginning of the sleep cycle. In other words, for good health and easy awakening, we must wake up at the end of REM sleep or at the beginning of the first stage of deep sleep.

RECOMMENDATION 2: Awakening should occur at the end of the sleep cycle (at the end of non-REM sleep or at the beginning of deep sleep phase 1)

But how to wake up at the end of the cycle? How to know that right now is the best moment to wake up, because we are sleeping? There are several options for solving this problem.

Wake-up time calculation.

1. Calculate the wake-up time in multiples of cycles of 90-120 minutes. Since there is a range here, we can try to first take it equal to 90 minutes and see how we feel at the moment of awakening. If there is discomfort, try a different cycle duration, for example, 100 minutes, etc. Do not forget that the cycle is when we have already fallen asleep. The time that we need to go to sleep (we have already gone to bed, but are still awake - the stage of falling asleep), we do not include in the cycle, but take into account "from above" (20 minutes falling asleep + 5 * 90 = 7 hours 50 minutes of sleep )
2. Go to bed for a long period of time (from a month) at the same time and get up without an alarm clock. Our body itself should begin to wake up at the most opportune moment)
3. Use special programs for tablets and smartphones. You run this program before you start sleeping and put your phone face down next to you on the pillow. The program analyzes your sleep during the night and determines the best moment to wake up from the time interval you set earlier. Programs are available for different platforms, one of the varieties of SleepTime.

Take a nap during the day.

Well, let's not forget about a short daytime nap, not very common in northern cultures, but very popular in hot countries. There is a lot of debate about whether daytime sleep is beneficial and what effect it has on the subsequent course of sleep phases during the night. Some of the latest research results were presented by Professor Tomohide Yamada from Tokyo (Dr Tomohide Yamada, University of Tokyo, Japan) at the annual conference of the European Association for the Study of Diabetes (European Association for the Study of Diabetes). According to research by a Japanese specialist, too much daytime sleep (60 minutes or more is considered to be) increases the risk of diabetes by 46%. The time recommended and harmless daytime sleep is, according to the result of the study, no more than 40 minutes.

Another study on a similar topic was conducted in China. The main goal was to identify how daytime sleep affects older people. The study involved 25,184 people (mean age 63.6 years). As a result of the study, it was found that prolonged daytime sleep (from 90 minutes or more) negatively affects primarily women and contributes to the development of metabolic syndrome.

So, we have recommendations that daytime sleep should not exceed 40-60 minutes. This is fully consistent with the knowledge of the functional features of sleep phases. If we allow up to 40 minutes of daytime rest, then our sleep does not have time to move into deep phases of sleep, which will make waking up more difficult and can cause a feeling of fatigue and “brokenness”.

RECOMMENDATION 3: Daytime naps should not exceed 40-60 minutes

Knowing what phases our sleep consists of and their functional significance is practical information that will help us organize sleep in the best possible way. Let's appreciate our body and help it please us with its performance, health and strength for many, many years.

All sleep is divided into two fundamentally different types - this is slow sleep and REM sleep. In turn, non-REM sleep is divided into 4 phases. It turns out that there are 5 phases of sleep in total.

slow sleep

It is also called the doze stage. It is characterized by thinking about and experiencing the problems that have arisen during the day. The brain, by inertia, tries to find a solution to the problems on which it worked while in the waking state. A person can see images that implement the solution to the problem.

There is a further decrease in muscle activity, pulse and breathing slow down. The brain gradually stops working. This stage is characterized by short bursts of auditory sensitivity. Several times a minute a person is in a state where it is very easy to wake him up.

Is transitional. The difference between the third and fourth phases of sleep lies in the number of delta oscillations. But we will not go into such details.

It is characterized by the deepest sleep. It is considered the most important, since at this time the brain receives the most complete rest and restores its working capacity. In the fourth phase of sleep, a person is difficult to wake up. Cases of sleep talking or sleepwalking occur during this phase.
The first two phases are considered superficial non-REM sleep, and the second two are considered deep. Non-REM sleep is also called orthodox sleep or non-REM sleep.

On the site http://androidnetc.org/category/neobxodimye you can download applications for android. For example, one of the proposed Sleep Time applications will analyze the vibrations of your body and determine what phase of sleep you are currently in. When the time for awakening comes, the most appropriate moment for your awakening will be chosen. Lots of useful apps! Go to the site and see for yourself.

REM sleep (REM sleep)

This stage is also called REM sleep (from the English rapid eye movements, which means “rapid eye movements”). As you may have guessed, REM sleep is characterized by accelerated movements of the eyeballs under closed eyelids - this is the first fundamental difference from non-REM sleep.

The second difference is that in the phase of REM sleep, the brain does not rest at all, but, on the contrary, is activated. The heart rate also increases, but the large muscles are completely relaxed.

And the most interesting thing is that it is most difficult to wake a person in the phase of REM sleep, although his state is closest to the state of wakefulness. Therefore, REM sleep is also called paradoxical sleep.
The purpose of REM sleep is not entirely clear. There are several assumptions about this:

1. In the stage of REM sleep, the brain sorts out the received information.
2. The brain analyzes the environmental conditions in which the body is located and develops an adaptation strategy. An indirect confirmation of this judgment is the fact that in newborns, REM sleep is 50%, in adults - 20-25%, in the elderly - 15%.

But there is one fact that does not cause controversy - the most vivid dreams come to us in REM sleep! In other stages, dreams are also present, but they are blurred and we remember them very poorly. Scientists also say that you will remember a dream well only if you wake up in REM sleep.

Sequence of sleep stages

Sleep begins with the 1st phase, which lasts approximately 10 minutes. Then the 2nd, 3rd, and 4th phases follow in sequence. Then, in reverse order - the 3rd, 2nd, and the phase of REM sleep begins. Together they form a cycle that repeats 4-5 times a night.

This changes the duration of different phases from cycle to cycle. In the first cycle, REM sleep is very short, more time is taken by deep slow sleep. But in the last cycles of deep sleep, there may not be at all. Usually one cycle is 90-100 minutes.

And now the most interesting. In what phase of sleep you wake up, your well-being depends. The most unsuitable for waking up is deep sleep. Waking up from a deep sleep, you will feel overwhelmed.

It is best to wake up after the end of the REM phase, that is, at the beginning of the first or second phase. Waking up from REM sleep is not recommended.
Now you probably have a question about how to make sure that you wake up in the right phase.

I will give only one thought on this matter. As already mentioned, in the stage of deep sleep, a person is quite difficult to wake up. Therefore, if your sleep is interrupted in a natural way, and not by an alarm clock, then you will most likely wake up in the right phase.

Now a little about the importance of fast and slow sleep. Some scientists say that REM sleep is a relic of the past, supposedly a person does not need it, just like an appendix.

The following facts are cited in support of this assertion:

If you forcibly limit the duration of sleep, then the duration of the deep phase of sleep practically does not change, the brain reduces the duration of REM sleep in the first place.

But this only proves that deep sleep is more important than fast sleep - no more!

Experiments were conducted when people were completely deprived of REM sleep for two weeks. At the same time, their health status did not worsen in any way.

Two weeks is not that long, considering that some people can go so long without sleep at all.

But other scientists conducted experiments on rats. As a result, after 40 days without REM sleep, the rats died.

The process of sleep is a very little studied phenomenon. Somnologists in the future will have to find answers to many controversial questions.
Well, we need to take care of our sleep and lead a healthy lifestyle!