Phases of human sleep. Stages of slow-wave sleep and REM sleep. What is the ratio of slow-wave sleep to REM sleep?

During sleep, an adult alternates between 2 main phases: rapid and slow-wave sleep. At the very beginning after falling asleep, the duration of slow phase, and before waking up the duration slow sleep The duration of REM sleep is shortened and lengthened.

A healthy adult begins sleep from the 1st stage. slow sleep, lasting 5-10 minutes. Next 2nd st. lasts 20 minutes. Then follow 3-4 tbsp., continuing for another 30-45 minutes. Then the sleeper again plunges into the 2nd art. slow wave sleep, followed by the first episode of REM sleep, which takes only 5 minutes. This is one cycle.

The initial cycle lasts approximately one and a half hours. During repetitions of cycles, the share of slow-wave sleep is shortened, and the share of fast sleep is lengthened. During the last cycle the duration fast cycle can reach one hour. A healthy adult experiences 5 sleep cycles during the night.

slow sleep

NREM sleep is also divided into certain stages:

The first is drowsiness with half-asleep visions. At this time, solutions to the day's problems may clearly appear in the brain.
The second is the so-called sleep spindles. At this time, consciousness turns off, but the person can be easily awakened due to increased perception thresholds.
The third is deeper sleep, in which sleep spindles are still preserved.
The fourth is the deepest sleep, which is sometimes called delta sleep. The duration of the deep sleep phase decreases from cycle to cycle.

Actually, the concept of delta sleep sometimes combines the penultimate and last stages. It is almost impossible to wake up a sleeping person during this period. This is precisely the stage in which nightmares, or nightmares, arise, but upon awakening the person does not retain memories of what happened. Normally, all 4 slow-wave stages of sleep of the 1st cycle occupy up to 80% of all sleep.

From the point of view, in this phase the body heals physically - cells and tissues are restored, self-healing occurs internal organs. During this period, the body restores its energy costs. During REM sleep, he restores his mental and intellectual resources.

What happens during delta sleep

During delta sleep, heart rate and breathing rates decrease, and all muscles relax. As this phase deepens, the number of movements in the sleeper becomes minimal, and it becomes difficult to wake him up. If you wake up the sleeping person at this time, he will not remember his dreams.

During slow-wave sleep, according to researchers of the phenomenon, restorative metabolic processes occur in tissues aimed at compensating for the catabolism that occurs during wakefulness.

Certain facts support this hypothesis. The delta sleep stage is prolonged in some cases:

after active physical work;
during a period of rapid weight loss;
with thyrotoxicosis.

If subjects are deprived of this phase artificially (by exposure to sound, for example), then they begin to complain of physical weakness and unpleasant muscle sensations.

Delta sleep also plays an important role in memorization processes. Experiments were conducted during which subjects were asked to memorize meaningless combinations of letters before going to bed. After three hours of sleep, they were woken up and asked to repeat what they had learned before going to bed. It turned out that the more delta waves were recorded during this period of sleep, the more accurate the memories were. The results of these experiments determined that the memory deterioration that is observed with prolonged sleep disturbances and insomnia is associated specifically with problems in deep sleep.

The experimental subjects react to deprivation of deep sleep in the same way as to complete sleep deprivation: 2-3 nights with the use of stimulation reduce performance, slow down the speed of reactions, and give a feeling of fatigue.

How long should deep sleep last?

Each person has their own individual norm for how much sleep they need. There are short sleepers, medium sleepers, and long sleepers. Napoleon was a short sleeper - he slept only 4 hours. And Einstein was a long sleeper - his sleep norm was at least 10 hours. And both were very effective figures. However, if a common person forced to reduce his quota, then he will probably be negative in the morning, immediately tired and angry.

Scientists at the University of Surrey conducted an experiment in which 110 healthy adults who had never experienced sleep problems took part. On the first night, participants spent 8 hours in bed and showed that: subjects aged 20-30 years slept 7.23 hours, 40-55 years old 6.83 hours, 66-83 years old - 6.51 hours. The same trend was observed for the time of deep sleep: 118.4 minutes in the first group, 85.3 in the middle group, 84.2 minutes in the oldest group.

The first thing that begins to suffer with a lack of delta sleep is the endocrine system. If there is a lack of deep sleep, a person does not produce growth hormone. As a result, the belly begins to grow. These people suffer from apnea syndrome: at night they experience short-term breathing stops, during which they may simply not breathe for up to 1.5 minutes. Then, out of a sense of self-preservation, the body gives the command to wake up and the person snores. This is very dangerous condition, during which heart attacks and strokes occur much more often. When treating the syndrome, people lose weight sharply because their hormone production improves. Sleep apnea causes irresistible daytime sleepiness, which is extremely dangerous if a person is driving at the time.

The norm for deep sleep in adults is from 30 to 70% of total sleep time. To increase its percentage you need to:

create a more efficient wake/sleep schedule (you need to go to bed and get up at the same time);
give the body physical exercise a couple of hours before bedtime (read more);
do not smoke, do not overeat, do not drink coffee, alcohol, energy drinks before bed (we compiled);
sleep in a comfortable room (ventilated, in the absence of extraneous sounds and light).

With the onset of old age, the duration of slow-wave sleep decreases. In 80 year olds long phase sleep becomes 62% less than twenty-year-olds. There are many factors that influence aging, but if the slow-wave sleep phase is also shortened, the aging process goes even faster.

How to measure your sleep

All 5 stages of sleep can be accurately divided only by the brain encephalogram, rapid eye movements, etc. modern research. If you just need to even out your sleep during the week, you can use special fitness bracelets. Fitness bracelets cannot read what phase of sleep you are in this moment the body is located, but they record the movements of a person in a dream. A fitness bracelet will help divide sleep into 2 phases - a person tosses and turns (phase 1-3), sleeps motionless (phase 3-5). The information on the bracelet is displayed in the form of a fence graph. True, the main purpose of this function of fitness bracelets is a smart alarm clock, which should gently wake up a person in the REM phase of sleep.

Discovery of delta sleep peptide

In the 70s, during experiments on rabbits, a group of Swiss scientists discovered the delta sleep peptide, which, when exposed to the brain, is capable of inducing this phase. Scientists isolated it from the blood of rabbits in deep sleep. Beneficial features substances are gradually being discovered to people over more than 40 years of research, he:

activates stress defense mechanisms;
slows down the aging process, which is facilitated by its antioxidant properties. The life expectancy of mice during experiments with its use increased by 24%;
has anti-cancer properties: slows down the growth of tumors and suppresses metastasis;
inhibits the development of alcohol dependence;
exhibits anticonvulsant properties, helps reduce the duration of epileptic seizures;
is an excellent pain reliever.

How to increase delta sleep time

A number of experiments have been conducted studying the effect of physical activity on delta sleep. The men exercised on an exercise bike for two hours. Daytime activities had no effect on sleep duration. Evening classes had a noticeable impact:

increased by 36 minutes total length sleep;
the period of falling asleep and dozing has been shortened;
delta sleep deepened;
the cycle lengthened from one and a half to two hours.

With the introduction of additional intellectual loads (tests in the evening, solution logical problems), changes were also recorded in the deep sleep phase:

the share of the most deep stage due to sleep spindles;
2nd cycle lengthened;
an increase in the functioning of the activating systems was recorded.

Any stressful situations cause a shortening of the delta sleep phase. Delta sleep is an obligatory participant in all changes in human living conditions. Increasing its duration compensates for any load.

List of used literature:

Feinberg I. Changes in sleep cycle patterns with age // J Psychiatr Res. - 1974 - Vol. 10, no. 3-4. - P. 283-306.
Legramante J., Galante A. Sleep and hypertension: a challenge for the autonomic regulation of the cardiovascular system. // Circulation: journal. - 2005 - Vol. 112, no. 6 (9 August). - P. 786-8. - PMID 16087808.
Morrissey M., Duntley S., Anch A., Nonneman R. Active sleep and its role in the prevention of apoptosis in the developing brain. // Med Hypotheses: journal. - 2004 - Vol. 62, no. 6. - P. 876-9.

A sleep-deprived person often faces problems feeling unwell, lack of strength. It loses efficiency, and the functionality of all body systems deteriorates. Night rest is a physiologically complex process. It consists of 5 constantly changing slow and fast phases. At this time, a person has time not only to relax, but also to rethink the information accumulated during the day. It is important for everyone to know what slow-wave sleep is, since it is what allows you to fully restore strength.

The first experiments to study night rest as a physiological process involved interrupting it at a certain time. After this, the subject’s sensations were recorded. They made it possible to establish that night rest consists of phases that change sequentially. The first scientist to study sleep was A.A. Manaseina. She determined that sleep at night is more important for a person than food.

In the 19th century, the scientist Kelschutter found that sleep is stronger and deeper in the first hours after falling asleep. Closer to the morning it becomes superficial. Maximum informative research began to be used after they began to use an electroencephalogram, which records electrical waves emitted by the brain.

Distinctive features of slow-wave sleep

The slow phase takes up about 85% of the total sleep volume. It differs from the fast rest stage in the following ways:

Consists of 4 stages.
At the moment of falling asleep, the movements of the eyeballs are smooth. At the end of the stage they freeze.
Dreams at this stage do not have a vivid plot. For some people they may be completely absent.
Disruption of the slow-wave sleep phase is accompanied by a person's irritability; he gets up tired and cannot get enough sleep. His performance declines and his health deteriorates. This happens due to the fact that not all neurochemical processes are completed.
Breathing and pulse become slow, a decrease occurs blood pressure, body temperature.
At this stage, complete muscle relaxation occurs.

Advice! As for REM sleep, a person wakes up at this stage without consequences for the body. Everyone is being activated life processes: increased heart rate, breathing. This rest phase is shorter.

The value of deep sleep

In order for a person to get enough sleep, he must rest properly. During slow sleep, growth hormone is synthesized and cells are intensively restored. The body is able to relax well, renew energy reserve. At this stage, the rhythms of all brain structures are regulated.

An adult has the opportunity to restore his immune system. If you sleep correctly, sufficient quantity time, the metabolism and removal of toxins from body tissues improves. In the slow-wave sleep phase, active processing of information received during the day occurs, consolidation of the learned material.

Elements constituting the Orthodox phase

The slow-wave sleep stage consists of several elements, which can be read about in the table:

Item name	Characteristic
Nap	During this time period, the ideas that appeared during the day are reviewed and finalized. The brain tries to find a solution to accumulated problems. There is a decrease in heart rate and breathing
Sleepy spindles	Here consciousness turns off, but these periods alternate with an increase in visual and auditory sensitivity. At this time, a person can be easily woken up. At this stage there is a decrease in body temperature
Delta sleep	This phase is considered transitional to the deepest sleep.
Deep delta sleep	During this period, a person may have dreams and his energy levels decrease. When it is necessary to awaken, this process is a severe stress for the body. Deep sleep occurs an hour and a half after the start of the first phase

These stages have a certain percentage:

Napping: 12.1%.
Sleep spindles: 38.1%.
Delta sleep: 14.2%.
Deep delta sleep: 23.5%.

REM sleep takes up 23.5% of the total time.

Duration of the slow stage per night

Many users want to know how long slow-wave sleep should last per night to prevent sleep deprivation. This cycle begins immediately after the sleeper enters an unconscious state. Next comes the deep phase. Sensory perception is switched off and cognitive processes are dulled. Normally, the nap period can last 15 minutes. The last three stages take about an hour. The total duration of the slow phase (excluding alternation with REM sleep) is 5 hours.

The length of this period is affected by age. In a child, this phase lasts 20 minutes, in adults under 30 years old – 2 hours. Further, it decreases: from 55-60 years - 85 minutes, after 60 years - 80. Healthy holiday should take at least 6-8 hours a day.

It should be noted that the amount of sleep per night is different for each person. Some people can sleep quickly and 4-5 hours will be enough for them, while for others 8-9 hours will not be enough. Here you need to pay attention to your feelings.

It is important to know! Determining the exact time required for a night's rest is done by trial. This will take 1-2 weeks. But we must not allow constant disruption of the slow phase.

The human condition during deep sleep

At night, the deep stage will be accompanied by complete relaxation muscular system, brain. The conductivity of nerve impulses changes, sensory perception is dulled. Metabolic processes and the functioning of the stomach and intestines slow down.

During this period, the brain requires less oxygen, blood flow becomes less active. Proper night's rest will be characterized by slowing down the aging process of tissues.

Reducing the slow phase: what is the danger

Depending on how long the slow phase of sleep lasts, a person will have wellness and performance. Its reduction is fraught with the emergence serious problems with health: clarity of consciousness is lost, appears constant drowsiness. Regular disruption of the normal duration and structure of sleep leads to chronic insomnia. A person has the following problems:

increased fatigue;
immunity decreases;
irritability increases, mood often changes;
are violated metabolic processes, mental functions and attention are dulled;
work becomes problematic endocrine system;
the risk of developing heart and vascular diseases increases;
performance and endurance decrease;
Insulin synthesis fails.

Attention! Decreased sleep leads to the development of atherosclerosis, diabetes mellitus, oncological pathologies. Comparative analysis showed that the slow and fast phases of night rest are equally important, although their characteristics will differ.

Regardless of whether a man or woman has a disturbed sleep structure, or how much a person sleeps, if he does it incorrectly, then rest will not give the desired result. To improve its quality, you need to follow the following recommendations from experts:

Stick to a bedtime schedule. It is better to go to bed no later than 11 pm. At the same time, it is advisable to wake up no earlier than 7 am (this indicator varies from person to person).
Before going to bed, you need to ventilate the room. The temperature in the bedroom should not exceed 22 degrees. To improve your sleep quality, you can take an evening walk in the fresh air.
A few hours before rest, you should not eat food that requires a long time to digest. IN as a last resort, you can drink a glass of warm milk.
Night rest should include the period after midnight to 5 am.
Drinking coffee, strong tea or alcohol in the evening is strictly prohibited.
If a person has difficulty falling asleep, then he can drink tea using soothing herbs (motherwort, valerian), take a relaxing bath with sea salt. Aromatherapy often helps you fall asleep.
It is important to choose a comfortable resting position.
Preference should be given to orthopedic devices for rest. The mattress should be flat and hard. Do not use a high headboard.
The room should be quiet and dark at night.
After waking up it is better to take cold and hot shower or do light exercises.

A proper night's rest, respecting its structure, is the key good health and good health. A person wakes up rested, productive, in in a great mood. Systematic lack of sleep will lead to serious violations functionality of the body that is not easy to get rid of.

Every night we all go through phases of sleep: rapid and slow sleep. Physiologically, sleep is a complex various processes, during which we can experience several cycles of these two phases.

For a long time it was believed that there was no way to study a person’s dreams and their influence on his physiology and psyche in any way. Initially they were studied on the basis of purely physical description processes - it was possible to determine the sleeper’s pulse, his arterial pressure and his body temperature. But about assessing the influence of sleep on mental and physical activity there wasn't even any talk.

With the advent of encephalography in the twentieth century, the possibilities for understanding the processes occurring during sleep have expanded significantly.

Every night's rest is necessary for a person; to some extent we can say that sleep is for a person more important than nutrition. A person deprived of sleep for only two or three days becomes irritable and loses emotional stability, memory lapses begin. Against the background of fatigue and mental retardation due to lack of sleep, a person falls into depressive state. It is believed that the maximum time a person can live without sleep is 11 days, after which irreversible changes occur in the brain, leading to death.

The main purpose of sleep for the body is to rest all its systems. For this purpose, the body “turns off” all senses and is almost completely immobilized.

Modern science presents sleep as a special period that has behavioral characteristics of the motor sphere and the autonomic nervous system. A feature of sleep is the alternating change of two states with almost opposite manifestations. They are called slow and fast sleep.

The surprising thing is that only together both phases - fast and slow sleep - can restore both the physical and mental strength of the body. By interrupting the night at the stage when only one of the cycles will be implemented, good rest the body will not receive it. The combination of fast and slow sleep renews the brain's performance and fully processes the information received during the past day. It is the complete completion of sleep cycles that facilitates the transfer of information from short-term memory to long-term memory.

Actually good sleep and is the final stage in solving the problems of the past day and a kind of “summing up” of its results.

Also, complete and proper rest during sleep improves the health of the whole body.

The following physiological processes occur only during night rest:

fluid balance is restored and the body is cleansed by removing excess moisture;
collagen protein is synthesized, which plays an important role in strengthening joints, blood vessels and skin;
The body absorbs calcium, which is necessary for bone and dental tissue.

These processes are quite lengthy, so for feeling normal You need to sleep about eight hours.

The duration of slow-wave sleep is equal to almost three-quarters of the total time of night rest, its features are as follows:

The slow phase is characterized by a general slowdown in metabolism, a significant decrease in the brain's response to external factors, relaxation of the entire body and general lethargy. Awakening is a very difficult time and leaves discomfort quite long time.

In the slow phase, muscle tissue is regenerated. It is also during this phase that the immune system is “rebooted”. Thus, its normal and complete completion is a guarantee of improved well-being.

Slow sleep promotes rehabilitation and healing of the body: cell renewal occurs and the functioning of all body systems improves. REM sleep is different in that it does not have such abilities.

In fact, slow-wave sleep is divided into four components, each of which has various characteristics. Let's look at the components of slow-wave sleep.

A person falling into a state of slumber despite the decline physiological processes, continues to work his brain and is thinking about and refining some of the most important ideas that he dealt with during the day. At the same time, the brain receives a sufficient amount of oxygen and works somewhat beyond its capabilities: various solutions to certain situations are searched for, optimal options. Often it is during the dozing phase that dreams appear that have positive and pleasant results. Final solutions to some known problems came to humanity during this phase. Mendeleev, Descartes, Bohr and many other scientists admitted that the final processing of their theories occurred precisely during dozing.

Sleepy spindles

This stage is also called the sigma rhythm due to the characteristic impulses observed on the encephalogram. Her distinctive feature is an almost complete blocking of consciousness, similar to that observed during anesthesia. The duration of this stage is half of the entire slow phase. It takes a very long time for the brain to prepare for deep sleep.

Notable is the fact that this activates special cells that separately block the channel of sound transmission to the brain

Delta sleep

A kind of “prelude” to the deep, it happens relatively quickly. During delta sleep, the amplitude of impulses in the brain decreases significantly, the impulses themselves become shorter - brain activity approaches its minimum.

From this stage, which begins about an hour and a half after the start of napping, we are already completely asleep. Brain activity is minimal, there is practically no reaction to any stimuli. It is almost impossible to wake up a person in this stage: even loud sounds, braking and quite strong painful sensations unable to interrupt it.

Dreams are present at this stage, but it is almost impossible to remember them - only fragments of images remain in memory. If it is possible to awaken a person during this stage, the rise will be extremely difficult and the body will finally recover to next period sleep may not come.

Another name for this phase is paradoxical or fast wave. There is a significant activation of life processes, primarily occurring in the brain. The transition from slow-wave sleep to fast sleep occurs quickly, and serious changes occur throughout the body.

Features of the REM sleep phase include:

Increased breathing and heart rate.
Frequent arrhythmias in the heart.
Decreased muscle tone.
A significant decrease in the activity of the muscles of the neck and diaphragm.
Promotion motor activity eyeballs with closed eyelids.
Clear memories of dreams seen during REM sleep, down to the smallest details, which is completely uncharacteristic of the slow-wave sleep phase.

With each subsequent cycle, the phases of slow and fast sleep alternate, which means that the latter has a longer and longer duration, however, its depth decreases. This happens to make it easier to get out of sleep cycles when you wake up. The prejudice that sleeping better in the morning than at night is wrong. By the third or fourth change of cycles of alternating sleep phases, it is much easier to wake a person.

The REM stage of sleep is unique in its own way. It is in it that the exchange of data takes place between consciousness and subconscious, and what was thought about during dozing again enters consciousness, but now supplemented various options that may happen.

REM sleep is usually divided into two stages: emotional and non-emotional. During the REM sleep phase, they can alternate several times, with the first phase always being slightly longer.

During REM sleep there is a significant change hormonal levels. According to researchers, it is REM sleep promotes daily reconfiguration of the endocrine system.

Thus, REM sleep seems to sum up all the mental activity of the brain for the entire day. Rest at this stage is necessary for a person so that he can adapt to possible options developments of yesterday's events.

This is why interrupting this phase sometimes leads to more undesirable consequences than interrupting slow-wave sleep. In this case, we are faced with the problem of not physical, but mental fatigue, leading to possible violations psyche. There is an opinion in the scientific community that if a person is deprived of REM sleep too often, it will undermine his psyche to such an extent that it can lead to death.

For the body, the fast phase is to some extent small stressful situation. The changes taking place in it are quite radical and can lead to some undesirable consequences. For example, most heart attacks, strokes and seizures occur during REM sleep. This is due, first of all, to the fact that the relaxed cardiovascular system is subjected to a sharp and sudden load.

It is impossible to say for sure which of the sleep phases - slow or fast - is better or more important, since each of them performs its own functions. If you try to imagine the entire dream in the form of a curved line, it will look like several “dives” into deep and slow sleep, followed by “ascents” into superficial, fast sleep. The time between such ascents and descents will be approximately one and a half to two hours.

According to physiologists, this one and a half hour time period is the main biorhythm human body, it manifests itself not only during rest, but also during wakefulness.

In an adult, the stages of night rest are distributed approximately according to the following ratios:

drowsiness - 12%;
sleep spindles - 38%;
delta sleep - 14%;
deep delta sleep -12%;
REM sleep - 24%.

The first four belong to the phase of slow-wave sleep, the last - to fast sleep. In addition, the phases of sleep are very different and do not replace each other immediately, but over the course of an intermediate state similar to drowsiness. It lasts about 5 minutes.

During the entire sleep period, 5-6 cycles occur full shift all stages. The duration of the stages may vary slightly from cycle to cycle. At the end of the last cycles, the intermediate state is the most sensitive and leads to normal awakening.

Awakening is an individual process and lasts from several tens of seconds to three minutes. At this time, the final recovery occurs normal functions organs and the emergence of clarity of consciousness.

The main differences between NREM and REM sleep

NREM and REM sleep are performed different functions. During each phase, the human body behaves differently. Often, the behavior of a sleeping person is purely individual, however, there are characteristics that are characteristic of all people, which are presented in the table.

Characteristic		Fast phase
State of the autonomic nervous system	Active work pituitary gland Accelerated synthesis of most hormones	Suppression of reflection spinal cord. The appearance of fast brain rhythms. Increased heart rate. The emergence of a “vegetative storm”
Brain temperature	Decrease by 0.2-0.3°С	Increase of 0.2-0.4°C due to blood flow and increased metabolism
Breathing Features	Loud and deep, there is a lack of rhythm	Uneven, often rapid breathing with delays due to dreams
Eyeball movements	At the beginning of the phase - slow, at the end - almost absent	There is constant rapid movement
Dreams	Dreams are rare; if they exist, they are calm character. It's hard to remember them	Bright and rich pictures and dreams, as a rule, contain a lot of active actions. Well remembered
Awakening	Associated with a depressed state, a feeling of fatigue. Difficulty waking up due to incompleteness chemical processes during the slow phase	Waking up at the beginning of the phase causes mental fatigue. In the end - light and fast, the body wakes up rested. In this case, the state is cheerful, the mood is good

Despite the rather large difference in the nature of the phases of slow and fast sleep, both have a deep physiological, functional and biochemical relationship and are the result of the joint work of the sympathetic and parasympathetic nervous systems.

Regulates slow-wave sleep internal rhythms brain areas and structures, fast contributes to their synchronization and harmonious functioning.

A dream, like all beautiful things, ends sooner or later. The physical and psycho-emotional state of a person depends on at what stage of sleep the awakening occurred.

The most unpleasant thing will be to awaken in the slow phase, when it has entered the deep stage. The best time to wake up will be between the end of REM sleep and the end of the first stage of the next cycle. Get up while active fast phase Not recommended.

If a person has slept well, then he is full of energy, cheerful and in high spirits. This often happens at the end of the dream.

During this period, his senses are activated, and the person responds well to external irritating factors that contribute to awakening:

Light from the window.
Sounds from the street or music.
Changes in ambient temperature.

If you wake up immediately, you will feel excellent. But, if you skip this time and take a nap a little more, then the body can “delay” into another slow cycle.

We often wake up shortly before the alarm clock. This is not surprising: the body itself adjusts its “internal clock” to the daily routine and the cycles occur in such a sequence that the fast phase ends at a time close to the moment the artificial clock is triggered.

If at this moment you tell yourself that such an awakening has occurred ahead of schedule, then you can fall asleep again and wake up in a deep stage, ruining your whole next day.

Therefore, the best awakening is one that occurs independently, without any external factors. It doesn't matter what time it is. If the body symbolizes to us that it has had enough sleep, we cannot be deaf to such a message.

However, in Lately began to appear on sale " smart alarm clocks”, which are connected via wireless sensors to the human body. They read the body parameters and use them to determine the time of awakening - at the end of REM sleep or during the transition from it to an intermediate state.

In any case, even if waking up was easy, do not rush to jump out of bed. The body needs to be given a few minutes to adapt all its systems to the new day. The main thing in this process is not to fall asleep again, think about some idea, get ready for the new day and go ahead!

Content

People have always been interested in the nature of sleep, because a person devotes a third of his life to this physiological state. This is a cyclical phenomenon. During 7-8 hours of rest, 4-5 cycles pass, including two phases of sleep: fast and slow, each of which can be calculated. Let’s try to figure out how long each stage lasts and what value it brings to the human body.

What are sleep phases

For many centuries, researchers have been studying the physiology of sleep. In the last century, scientists were able to record bioelectrical oscillations that occur in the cerebral cortex during sleep. They learned that this is a cyclical process that has different phases, replacing each other. An electroencephalogram is taken using special sensors attached to a person’s head. When the subject is sleeping, the devices first record slow oscillations, which subsequently become frequent, then slow down again: there is a change in the phases of the dream: fast and slow.

Fast phase

Sleep cycles follow one after another. During the night's rest, the fast phase follows the slow phase. At this time, heart rate and body temperature increase, the eyeballs move sharply and quickly, and breathing becomes frequent. The brain works very actively, so a person sees a lot of dreams. The REM sleep phase activates the work of all internal organs and relaxes muscles. If a person is woken up, he will be able to tell the dream in detail, because during this period the brain processes the information received during the day, and an exchange occurs between the subconscious and consciousness.

Slow phase

Fluctuations in the slow rhythm electroencephalogram are divided into 3 stages:

Nap. Breathing and other reactions slow down, consciousness floats away, different images appear, but the person still reacts to the surrounding reality. At this stage, solutions to problems often come, insights and ideas appear.
Shallow sleep. There is a blackout of consciousness. Heart rate and body temperature decrease. During this period, the dreamer is easy to wake up.
Deep dream. At this stage, it is difficult to wake a person. The body actively produces growth hormone, regulates the functioning of internal organs, and tissue regeneration occurs. At this stage, a person may experience nightmares.

Sequence of sleep phases

In a healthy adult, the stages of dreaming always occur in the same sequence: 1 slow phase (drowsiness), then 2, 3 and 4, then the reverse order, 4, 3 and 2, and then REM sleep. Together they form one cycle, repeating 4-5 times in one night. The duration of the two dream stages may vary. In the first cycle, the deep sleep phase is very short, and last stage it may not exist at all. The sequence and duration of stages can be influenced by the emotional factor.

Deep dream

Unlike REM sleep, the deep phase has a longer duration. It is also called orthodox or slow wave. Scientists suggest that this condition is responsible for restoring energy expenditure and strengthening the body's defense functions. Research has shown that the onset of the slow wave phase divides the brain into active and passive areas.

In the absence of dreams, the areas responsible for conscious actions, perception, and thinking are switched off. Although during the deep phase heartbeat And brain activity decrease, catabolism slows down, but memory scrolls through already learned actions, as evidenced by external signs:

twitching of limbs;
special breathing order;
playing different sounds.

Duration

Each person has an individual norm of delta sleep (deep phase). Some people need 4 hours of rest, while others need 10 to feel normal. In an adult, the deep phase takes up 75 to 80% of all sleep time. With the onset of old age, this duration decreases. The less delta sleep, the faster the body aging. To increase its duration, you must:

create a more effective wake/rest schedule;
before a night's rest, give the body a couple of hours physical activity;
do not drink coffee, alcohol, energy drinks, do not smoke or overeat shortly before the end of wakefulness;
sleep in a ventilated room in the absence of light and extraneous sounds.

Stages

The structure of sleep in the deep phase is heterogeneous and consists of four non-rem phases:

The first episode involves memorizing and understanding the difficulties that occurred during the day. At the stage of drowsiness, the brain seeks solutions to problems that arose during wakefulness.
The second phase is also called “sleep spindles.” Muscle movements, breathing and heart rate slow down. Brain activity gradually fades, but there may be brief moments of particularly acute hearing.
Delta sleep, in which the superficial stage changes to a very deep one. Lasts only 10-15 minutes.
Strong deep delta sleep. It is considered the most significant because throughout the entire period the brain reconstructs the ability to work. The fourth phase is distinguished by the fact that it is very difficult to wake up a sleeping person.

REM sleep

REM (rapid eye movement) - the phase or from the English rem-sleep is distinguished by the increased work of the cerebral hemispheres. The biggest difference is the rapid rotation of the eyeballs. Other characteristics of the fast phase:

continuous movement of organs visual system;
vivid dreams are brightly colored and filled with movement;
independent awakening is favorable, gives good health and energy;
Body temperature rises due to vigorous metabolism and strong blood flow.

Duration

After falling asleep a person most spends time in the slow phase, and REM sleep lasts from 5 to 10 minutes. In the morning the ratio of stages changes. The periods of deep breathing become longer, and deep periods become shorter, after which the person wakes up. Fast stage much more important, therefore if it is interrupted artificially, it will adversely affect emotional state. The person will be drowsy throughout the day.

Stages

The fast phase, also called paradoxical dream, is the fifth stage of dreaming. Although the person is completely immobile due to complete absence muscle activity, the state resembles wakefulness. The eyeballs under closed eyelids periodically make rapid movements. From stage 4 of slow-wave sleep, a person returns to the second, after which the REM phase begins, which ends the cycle.

The value of sleep by hour - table

It is impossible to say exactly how much sleep a person needs. This indicator depends on individual characteristics, age, sleep disturbance and daily routine. A baby may need 10 hours to restore the body, and a schoolchild – 7. The average duration of sleep, according to experts, varies from 8 to 10 hours. When a person correctly alternates between fast and slow-wave sleep, even in a short period every cell in the body is restored. Optimal time for rest is the period until midnight. Let's look at sleep efficiency by hour in the table:

Beginning of sleep	The value of rest

Best time to wake up

If you look at the dream value table, you can see that the time from 4 to 6 in the morning brings less benefits for rest. This period is the best for awakening. At this time, the sun rises, the body is filled with energy, the mind is as clean and clear as possible. If you constantly wake up with the dawn, then fatigue and illness will not be a problem, and you can do much more in a day than after waking up late.

What phase is best to wake up in?

The physiology of sleep is such that all stages of rest are important to a person. It is advisable that 4-5 complete cycles of 1.5-2 hours pass per night. The best time to get up varies from person to person. For example, it is better for owls to wake up between 8 and 10 am, and larks get up at 5-6 am. As for the dream stage, everything is ambiguous here too. From the point of view of the structure and classification of phases best time for awakening - those couple of minutes that occur at the end of one cycle and the beginning of another.

How to wake up during REM sleep

As the cycles repeat and the duration of the slow phase increases to 70% of the night's rest, it is desirable to catch the end of the REM stage to awaken. It is difficult to calculate this time, but to make your life easier, it is advisable to find the motivation to get up early in the morning. To do this, you need to learn, immediately after waking up, not to lie idle in bed, but to spend breathing exercises. It will saturate the brain with oxygen, activate metabolism, and give a charge of positive energy for the whole day.

How to calculate sleep phases

Self-calculation is difficult. You can find circadian rhythm calculators on the Internet, but this method also has a drawback. This innovation is based on average indicators and does not take into account the individual characteristics of the body. Most reliable method calculation - contact specialized centers and laboratories, where doctors, by connecting devices to the head, will determine accurate data on signals and oscillations of the brain.

You can independently calculate the stages of a person’s sleep something like this. Duration (average) slow stage– 120 minutes, and fast – 20 minutes. From the moment you go to bed, count 3-4 such periods and set the alarm clock so that the time you get up falls within a given period of time. If you go to bed at the beginning of the night, for example at 22:00, then safely plan to wake up between 04:40 and 05:00. If this is too early for you, then next stage for proper ascent will be in the time interval from 07:00 to 07:20.

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Attention! The information presented in the article is for informational purposes only. The materials in the article do not encourage self-treatment. Only qualified doctor can make a diagnosis and give treatment recommendations based on the individual characteristics of a particular patient.

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Despite the fact that the site already has an article about sleep phases, it seems correct spelling one more article in light of what has appeared new information about sleep cycles and the amount of time it takes a person to get enough sleep.

In order not to duplicate information, I refer everyone to the article Phases of Human Sleep. And in this article we will only give a brief overview of the most necessary points regarding the phases of sleep.

Another thing is sleep cycles. It is the required number of sleep cycles that gives us the opportunity to feel great in the morning after waking up. Moreover, each individual person may differ markedly from others in the number of necessary sleep cycles and, as a result, the time spent on night sleep.

In addition, I think it will be interesting to learn about what capabilities the human body has to compensate for the lack of sleep, both for the previous lack of sleep and for the future.

Let's look at all this in order.

Sleep phases

The sleep phases of any person consist of only two groups:

Non-REM sleep phase (consists of several types of sleep);
REM sleep phase.

These two sleep phases constantly alternate throughout a person’s entire sleep time, forming a single completed sleep cycle. That is, the sleep cycle consists of 1 phase of slow sleep and 1 phase of REM sleep. The duration of the sleep cycle usually ranges from 1 to 1.5 hours. Then a new cycle of similar duration begins.

Non-REM sleep stages initially occupy up to three-quarters of the total duration of the sleep cycle. But with each new cycle, the duration of the sleep phase within a given cycle changes towards reducing the duration of slow-wave sleep and increasing the rapid phase.

According to available data, somewhere after 4 o'clock in the morning, the phase of slow sleep (deep type) completely disappears, leaving only REM sleep.

What happens during non-REM and REM sleep?

The human body needs slow-wave sleep for recovery physical functions. At this time, the process of renewal of cells and internal structures occurs, energy is restored, muscles grow, and hormones are released.

During the REM phase of sleep, work occurs at the level of mental and emotional spheres: recovering nervous system, information is processed, memory and other structures of the body are prepared.

It turns out that each phase of sleep is extremely important for the next day of the body’s functioning.

Sleep cycles

But during one phase of sleep, the body does not have time to make all the necessary changes. Therefore, in order to fully restore and prepare the body for further activities Several repeating cycles are needed throughout the day.

Today, scientists say that the average person needs 5 repeating sleep cycles. This adds up to about 7-8 hours of sleep a night.

However, there are a fair number of people who have deviations in the number of cycles in one direction or another.

There are people who are able to fully recover in just 4 sleep cycles. They often only need 4-6 hours of sleep during the night to feel great the whole next day.

On the other hand, many people feel constantly groggy if they sleep less than 9 hours a night. Compared to other people who sleep fewer hours, such people look lazy. However, if you understand that they just need not 5, but 6 sleep cycles at night, then everything falls into place. 6 sleep cycles of 1.5 hours each give you 9 hours of sleep at night.

How much sleep do you need to get enough sleep?

To get enough sleep, each individual person needs to sleep exactly as many sleep cycles as his body requires. Usually this is 4-6 sleep cycles.

At the same time, the duration of sleep will also fluctuate considerably, because... Each person has their own sleep cycle length.

Scientists recognize 4 sleep cycles as the minimum that allows the body to more or less restore its strength. But at the same time, it is necessary to ensure that all these 4 sleep cycles are completed before 4 o’clock in the morning. This will completely complete all the body’s work to restore physical structures.

In any case, every person knows approximately how many hours of sleep he needs to feel normal. Based on this, we can conclude about the required number of sleep cycles.