Study of sleep phases and their impact on proper rest. Phases of human sleep - the influence of slow and fast sleep What is better deep or light sleep

Rest refers to a necessary phenomenon through which processes are carried out: replenishment of energy and physiological costs. Scientists distinguish 2 phases of sleep - slow and fast.

Due to individual characteristics and excessive workload at work, it has become necessary to calculate an acceptable time to wake up in the morning. With correct calculations with the sunrise, a person will have a paradoxical result: high spirits, improved performance in any area. In addition, concomitant diseases such as insomnia will not develop.

The value and functions of sleep

An acceptable and recommended sleep period for adults is considered to be up to 12 am. Only at this moment is the human body able to restore the energy and physiological activity required for full performance.

The table shows valuable hours for a specific time period.

Times of Day	The value of sleep per hour
19-20 hours	7 o'clock
20-21 hours	6 hours
21-22 hours	5 o'clock
22-23 hours	4 hours
23-24 hours	3 hours
0-1 hour	2 hours
1-2 hours	1 hour
2-3 hours	30 minutes
3-4 hours	15 minutes
4-5 hours	7 minutes
5-6 hours	1 minute

Based on the above data, you can clearly see how important it is to go to bed on time. This affects the performance of the whole organism, and therefore shapes the further mood and well-being of a person.

Several main functions have been identified through which it becomes possible to form an idea of the benefits:

Internal organs and muscle tissue remain in a relaxed state at night, gaining strength.
During the day, a person expends a lot of energy for full-fledged activities, but only during sleep are the reserves replenished.
A lot happens when you're on vacation necessary processes dictated by the brain. This is the removal of waste and toxins, rebooting the central nervous system, cleansing the brain center.
Also, during sleep, long-term memory is formed, which includes accumulated information. This includes understanding what you see and consolidating new skills.
The main component is the analysis of the state of internal organs; if violations are identified, they should be eliminated. As a result, immunity improves, because new cells are formed during sleep.

Sleep is a necessary component in the life of every person. Without it it is impossible to live to the fullest. A necessary requirement is that you need to fall asleep at the recommended interval, because this can increase efficiency and prevent the development of certain diseases.

Cycle duration

Sleep is a state of consciousness of all living things, which includes 5 stages. They replace each other during the night's rest. The occurrence is explained by the activation of brain centers.

For an adult who does not have serious health problems, falling asleep begins with a nap. It doesn't take much time - only 10 minutes. After this, stage 2 enters. Lasts a little longer - 20 minutes. The remaining two stages take at least 45-50 minutes.

As soon as initial process, consisting of 4 stages, passes, and the action of stage 2 occurs again. At this moment the first episode appears REM sleep. But it doesn’t last long – 5 minutes. Such sequential processes are formed into cycles. The first one takes 1.5 hours or a little longer. Afterwards, the cyclicity resumes, but slow-wave sleep disappears. This is because REM sleep comes into play. Sometimes it takes 60 minutes.

Important! With proper rest, approximately 5 cycles. The sequence and duration vary slightly, depending on the individual characteristics of the body.

Most studies confirm that the fast and slow phases are characterized by of different durations in a ratio of 1:4. In this case, the first spends 85% of the rest time, but the second accounts for 15%. One cycle lasts 1.5 hours. It is important for a person to sleep 6-8 hours. Based on this, the cycles can be repeated 6 times. But the meanings are variable, depending on the specific case.

In young children, the process takes place in a slightly different sequence. REM sleep predominates, which is gradually replaced. Initially, it accounts for 50%, and as the baby develops, this figure decreases to 25%.

In an adult, the stages should tend to repeat in equal sequence. However, due to age-related characteristics and serious pathologies, it is possible to observe some disturbances in normal sleep. Elderly people often face problems of insomnia, because the fast phase makes up no more than 18%, and the slow phase is completely absent.

However, there are other reasons quality rest: diseases of the brain or spinal cord. In this case, it is impossible to sleep normally; there is superficial sleep. It is rare, but it is observed that a person does without rest at all, even short.

Slow phase

Certain brain centers are involved in the formation of slow-wave sleep: the hypothalamus, thalamic nuclei, and the inhibitory department of the moruzzi.

Important! The main feature of slow sleep is the formation of new cells and structures, tissue restoration. This process must occur at rest with the participation of certain hormones, amino acids and proteins.

The end result of anabolic processes is considered to be the replenishment of energy that is lost during performance during the day. Their activity begins from stage 2, because at this moment complete relaxation occurs. Therefore, such a period is considered favorable for restoring lost energy and physiological reserves.

Important! It has been proven that moderate physical activity per day helps prolong stage 4 slow phase.

When falling asleep, certain rhythms appear, which depend on the good illumination of the room by sunlight. The onset of dusk signals a decrease in some activity. At this moment, the first sleep triggers are observed: yawning and weakness.

Each stage has a specific time interval. So, 8% is spent on the third, and 15% of the entire period spent on sleep is spent on the fourth. Many attribute the slow phase to the restoration of energy resources. Only it is fundamental in understanding actions and memories.

The main signs of this stage of sleep are considered to be loud breathing, which gradually becomes rarer and less deep than during wakefulness. There is a decrease general temperature, activities muscular system and eye movements. During the slow phase of sleep, a person can see minor dreams; on the encephalogram, slow and long waves begin to predominate.

The first stage is drowsiness

It refers to stage 1 of falling asleep. In this state, the sleeper is able to see phenomena and actions that bother him while awake. In addition, this has a clear characteristic:

heartbeat weakens;
breathing slows down;
the temperature drops;
you can catch the slow movements of the eyeball.

Also, an altered state is recorded in a brain hologram, accompanied by surges in mental activity. At the same time, it is recorded that a solution comes difficult situation, which was difficult to resolve in the process of life. Main fact: awakening a person from stage 1 slow-wave sleep is not difficult.

Stage two - light sleep

During shallow sleep, the consciousness of reality gradually begins to turn off, but it is still possible to react to voices or sounds. At the same time, certain processes occur in a sleeping person: a decrease in temperature, any activity weakens, and pressure drops. With repeated studies, the sequence of stages of the slow phase is comparative (with the spindle), because over time all actions decay. Ultimately - immersion in a deep state.

Stage three - slow-wave sleep

A somewhat different state develops at this stage, since all movements come to naught. This can be verified through brain research. At the same time, the pulsation is weak, sighs become more frequent, the pressure level drops, and the pupils practically do not move. Blood flow to muscles and tissues is also manifested, and growth hormone is formed. All this characterizes the process that has begun in the body to replenish energy.

Stage four - deep sleep

The last stage is responsible for complete immersion in sleep. The phase is accompanied by a blackout of consciousness; it is impossible to even feel, feel or hear anything. That is why there are no special unexpected manifestations from the body: breathing is difficult to observe, extraneous movements of the eyeballs or body parts are not observed.

In the state of the deep phase, it is almost impossible to raise a sleeping person to his feet. If this is done, poor orientation in space, slower reactions, bad feeling, it is not possible to catch the ghostly thing. Sometimes people wake up in a good mood and experience nightmares. But this stage is not felt upon awakening.

Basically, stages 3 and 4 are classified as one, in which case their duration is about 40 minutes. High-quality and timely rest creates activity for work for the coming day. If stage deep sleep will be complete, it is possible to remember any information after waking up.

Fast phase

When rest is reorganized into a fast phase, unusable knowledge and skills are cleared in the emotional and intellectual areas. At this time, active activities take place:

By recovery nerve cells. There is an opinion that this is impossible, but these are unreliable assumptions.
By understanding the information received during the day.
At the start of preparations for mental activity.

Due to the existence of a single stage fast phase its duration increases, which is 15%. Its main goal is to process the received information with the possibility of its further application. In addition, this phase is mandatory, because it is required for the complete restoration of the nervous system.

Significant changes were revealed during REM and slow-wave sleep. This manifests itself in characteristic actions and movements, some of which can be observed visually:

Difficulty breathing when exhaling deeply.
Deviations from the normal heartbeat.
Muscle tone weakens, which can be more clearly observed in the neck of the mouth.
The pupils perform unconscious movements at an accelerated pace.

In this phase, dreams are the most emotional. They may be dominated by bright and significant moments from life or various situations transferred the previous day.

If a sleeper is awakened in the REM phase, he will clearly and clearly reproduce the dream. Awakening in this phase is easy because no discomfort is felt. On the contrary, your mood lifts and your well-being improves.

Through alternating phases, some changes are revealed with their effect on the body. The next morning, the likelihood of waking up in the fast phase increases, but the slow phase decreases. If it is impossible to go to bed at the conventional time, the fast phases will be shortened, but the slow phases will not be in danger.

Features of awakening in each phase of sleep

Sleeping is characterized by heterogeneity, and several phases have been identified that particularly affect the body. Each of them has specific phenomena brain system. The main task is to replenish energy and physiological resources.

If we talk about the correctness of phase awakenings, then you need to have information about each one. First, it is worth highlighting at what stage the interruption occurred. Problems will arise in the slow phase, because the most significant processes are being restored.

Awakening in the fast phase is facilitated, regardless of the colorful and vivid moments that can be seen in dreams. But the absence of this phase for a long time can negatively affect a person’s well-being, undermining psychological background. She is the link between consciousness and subconscious.

How to calculate the optimal time to wake up

All stages of sleep play an important role for humans. This will allow the body to restore strength and energy. The best solution is to adhere to the regime without breaking it. It is good if the cycles are completed by 4:00, since slow-wave sleep gradually declines after midnight. It is not necessary to do this, perhaps sleep more. It allows the nerves to recover at this very time when the fast phase begins.

To ensure quality rest that has beneficial effects, it is important to go to bed early. This will help maintain the duration of the phases.

Most people are curious if there is a special technique that would make it possible to calculate the best time to wake up on their own. So that at the same time you feel a surge of strength, with a further desire for mental and physical labor. Dymaxion is a common technique that involves sleeping for 30 minutes 4 times a day.

Using the slow and fast phases of sleep, how to get enough sleep? If awakening occurs in the slow phase, then fatigue is guaranteed. Therefore, it is better to do it in a quick phase. Careful calculations will allow you to track right time. This is easy to do; you just need to build a graph. But you are also allowed to use a calculator.

Based on somnological studies, it is known that sleep cycles take 2 hours, with fast sleep only 20 minutes. Using this data, it becomes possible to calculate an acceptable time to wake up.

However, full recovery requires 6-8 hours. After making the calculations, you should set the resulting value on the alarm clock face.

You can only find out the positive effect of awakening in the fast phase on your own; for this you need to try it. But this does not mean that you will be able to fall asleep right away. Therefore, when making calculations, it is important to leave a little time in reserve.

Human sleep phases by time table

In a dream, a person arrives at one stage: fast or slow. The special features of each of them can be found in the table below:

slow sleep	REM sleep
Napping is the first stage. It is characterized by vivid thoughts and memories that arise on a subconscious level. At this moment, the sleeper is in a superficial sleep, which lasts 5-10 minutes.	Fast is a separate and final stage. At this moment the person is in a state of activity. However, his movements are constrained, because motor function absent due to paralysis. The subconscious mind works harmoniously, so you can remember a lot useful information received per day. Awakening is not easy. This may have a negative impact on mental state. The fast phase takes 60 minutes.
When it is shallow, characteristic manifestations are possible: consciousness is switched off, but the auditory reference point (external voices, sounds) is heightened. For this very reason, sudden awakenings often occur. The duration of the stage is only 20 minutes.
The third stage is characterized by obvious immersion in sleep.
The fourth stage involves deep sleep. It is difficult to wake up a sleeping person. At the same time, dreams are clearly expressed. A person may have a disease - sleepwalking. The next morning it is difficult to remember what you dreamed; only some moments are remembered. More often, stages 3 and 4 are combined into one, each lasting about 45 minutes.

The table describes the phases of human sleep by time and characterizes the stages occurring in a specific phase. With the completion of all stages, the first cycle comes to an end. Sleep should be cyclical, so for quality rest the body must go through 5 cycles. The stages replace each other gradually. Doctors recommend getting at least 8 hours of sleep. If you constantly violate the recommendations, you can develop a disease - a mental disorder.

Sleep takes place in 2 phases: slow and fast. In young children, the fast phase predominates, which differs from adults. At the moment of sleep, it is possible to see the movements of the eyeball, while the baby has colorful dreams. Muscle tone weakens, but this does not affect the nasopharynx and eyes. Movements are limited.

It is known that during the growth and development of a child, the need for sleep is paramount. But everyone decides for themselves how much sleep they need. This is dictated by the body, namely individual characteristics: physiological, mental.

The norm for a child is determined depending on age guidelines:

1-2 months - 18 hours;
3-4 months - 17-18 hours;
5-6 months - 16 hours;
7-9 months - 15 hours;
10-12 months - 13 hours;
1-2 years - 13 hours;
2-3 years - 12 hours;
3-5 years - 10-13 hours;
6-13 years – 9-11 hours;
teenagers 8-10 hours.

Over time, children spend fewer hours resting in order to get a good night's sleep. This is dictated by changing needs and increased load on the brain. The most active ones need little time at all to gain strength for a productive day.

NATALIA EROFEEVSKAYA

Duration and quality of sleep– criteria that influence many factors: mood, well-being, feeling of cheerfulness. In preparation for a new day, we try to go to bed early, but in the morning we wake up exhausted and lethargic. On another day, on the contrary, after a short sleep, we wake up on our own, feeling cheerful and strong. Why does this happen and how to learn to get enough sleep? To answer these questions, we will analyze the phases of human REM and NREM sleep in time and their characteristics.

Discoveries of scientists

Today, sleep is an understandable physiological state. But it was not always so. For a long time scientists could not track what changes occur in a person during rest. The topic was closed and difficult to study. In the 19th century, they assessed a person’s posture, measured blood pressure and temperature, and took other indicators. For detailed study, sleepers were awakened and changes were recorded.

Hand turns off alarm clock early in the morning

Early attempts at sleep intervention have yielded results. Scientists have found that sleep goes through stages of varying duration rapid and deep sleep of a person, and their importance is great, since it affects all indicators of the body. The German physiologist Köllschutter found that deep sleep occurs in the first hours of rest, and then it turns into superficial sleep.

After the discovery of electric waves, scientists took a complete picture of what was happening to the sleeper. An electroencephalogram helped to understand what was happening to a person during rest. In this case, the subject did not have to be woken up. Thanks to new technologies, it has become known that sleep goes through 2 phases: slow and fast sleep.

Stages of slow-wave sleep

Orthodox sleep is divided into stages. The stages differ in the duration and depth of rest. Let's look at the stages of slow-wave sleep:

First. Occurs after a person closes his eyes. The first stage is called napping. A person is not yet falling asleep; the brain is in an active stage. Within 10–15 minutes. the vacationer processes information that happened during the day. During this period, solutions are found to the questions that tormented a person.
Second. At this stage, “sleep spindles” appear. They occur at intervals of 3–5 minutes. During their passage, consciousness is completely switched off. In between sleep spindles, a person is sensitive to what is happening around him. He hears voices or sounds. This feature allows the mother to hear the baby’s cry at night. If you call a sleeping person by name, he will immediately wake up. Physiological changes come down to a decrease in muscle activity and a slower heart rate.

During the second slow phase of sleep, a person hears sounds

Third. Stage of delta sleep or transitional. “Sleep spindles” are preserved and become longer lasting. Delta oscillations are added to them. The third stage is called preparatory stage before deep sleep.

Fourth. At this stage, the pulse quickens and blood pressure rises. The person falls into deep sleep. Dreams during this period are unclear and blurry. If the vacationer wakes up during the fourth stage, he will not remember what he dreamed.

People who sleepwalk or talk in their sleep do not remember anything the next morning. This is due to the fact that all events take place in deep stage sleep. Even if you interrupt the sleepwalker, he will not understand why he is not in bed and how he ended up in another room. It is at this stage that people have nightmares.

Duration of deep sleep directly depends on the person’s age and physical condition his body. For example, the duration of a child's deep sleep phase is 20 minutes, but the quality of sleep is completely different than that of most adults: it is much stronger, children may not respond to external stimuli (sound, light, touch). Thus, even the smallest ones restore energy, “reboot” the body’s systems, and charge the immune system.

How long does the deep sleep phase last? The deep sleep phase, the duration of which varies depending on the specific stage, generally lasts one and a half to two hours. Of these, 5-10 minutes are “allocated” for napping, 20 minutes for the second stage (slowing breathing and heart rate), and 30-45 minutes for the third and fourth phases.

The girl sleeps sweetly, hugging a pillow

Features of REM sleep

After deep sleep ends, REM sleep begins. The fifth stage was discovered by Kleitman in 1955. The recorded indicators made it clear that the indicators of the body during REM sleep in humans are similar to the state of wakefulness. The REM sleep phase is accompanied by:

constant movement of the eyeballs;
significant decrease in muscle tone;
emotionally charged and action-packed dreams;
complete immobility of a person.

How long does REM sleep last? In total, shallow sleep makes up 20-25% of the average night's rest time, i.e. one and a half to two hours. One such phase lasts only 10-20 minutes. The most vivid and memorable dreams come during the REM sleep stage. If a person is awakened during this period, he will fully tell what he dreamed.

Baby is sleeping

Why are sleep phases needed?

A person’s well-being is inextricably linked with rest and sleep. No wonder. In the first months of life, a little person has a strong connection with nature and obeys its laws. As adults, we make decisions about how much sleep we need. Often untrue, so the mental is disturbed, emotional condition person - that is why it is important to know the frequency of fast and deep stages in night sleep and be able to calculate the stages of sleep for the time of awakening.

Scientists calculated sleep phases and after a series of studies came to the conclusion that 4–5 cycles pass per night. During this period, the person is restored. During slow-wave sleep, energy expended during the day is replenished. REM sleep is short in the first cycles, then lengthens. During the fifth phase, a person processes information and builds psychological protection, adapts to the environment. Knowing how to calculate the sleep cycle, it is possible to learn how to regulate the body’s energy capacity and its vital functions as a whole.

Studies done on rats have shown that Lack of REM sleep leads to death. The rodents were deliberately awakened, preventing the rats from entering the fifth stage. Over time, the animals lost the ability to fall asleep, after which they died. If the sleeper is deprived of the fast phase, the person will become emotionally unstable, prone to irritation, mood swings, and tearfulness.

Girl sleeping with hand on alarm clock

How to calculate sleep phases to know when is the best time to wake up?

Let's take as a basis that one cycle lasts for 90 minutes. Long REM sleep is required for proper rest. Therefore, at least 4 cycles should pass overnight. Waking up during slow-wave sleep makes a person groggy and lethargic. So, we need to calculate how to wake up during REM sleep: The fifth phase is characterized by active brain function, so awakening occurs gently and painlessly.

Let's summarize. To feel cheerful in the morning, the duration of sleep and awakening after the completion of the fifth phase are important. For an adult, the ideal sleep time is 7.5–8 hours. The best option is self-awakening, no alarm or phone signal.

If during the day you feel weak and want to take a nap, then allow this luxury. To avoid harm, record your rest time. If you have slept enough time at night, close your eyes for 15–20 minutes. This is how long the first stage of slow-wave sleep lasts. You will not have time to fall asleep, but you will feel that fatigue has been relieved. If night sleep was short-lived, then go through one cycle during the day. Sleep for 1–1.5 hours.

Conclusion

The data given is approximate, but the essence is clear. For normal life human body phase sleep is necessary. It is important to wake up after completing 4–5 cycles. It’s ideal when you wake up on your own. Daytime sleep will not harm you if you do not allow the second phase to enter or if you go through one full cycle.

January 20, 2014, 11:36

A person's proper sleep helps restore all functions of the body. During rest, physical strength and energy balance are restored, information received during the day is sorted and processed, the immune system is strengthened, and other important processes occur. The phenomenon of sleep has not been fully studied by scientists, but there is research data that helps us better understand it and understand why it is beneficial for health. During the night we are in different phases of sleep, during which certain changes occur in the body.

Dream scenario

Sleep has two main phases: slow (orthodox, deep) and fast (paradoxical, superficial). The slow-wave sleep phase is the beginning of night's rest; it takes up three-quarters of the total time we spend in the arms of Morpheus. Next comes the REM sleep phase, during which brain activity increases. Our body does not sleep, consciousness and subconsciousness exchange data, information is filtered, which improves our cognitive abilities.

NREM sleep and the following REM sleep together constitute one cycle. It lasts for the average person about 1.5-2 hours. In total, we go through 4 to 6 cycles per night, at the end of which we should get a good night’s sleep.

It is noteworthy that slow-wave sleep becomes shorter and shorter with each new cycle, and fast sleep becomes longer. In order for the restoration of body functions to take place fully, all cycles must be completed before 4 am. After this, rest continues, but the orthodox phase no longer occurs.

You need to wake up precisely at the moment of REM sleep, since at this time all our systems are activated.

Alternating stages of slow-wave sleep

Our falling asleep begins with slow sleep. It is divided into 4 stages, during which different processes occur in the body. With the help of electroencephalographic studies, scientists were able to obtain an electrical picture of sleep and find out how long each stage lasts, how the brain behaves, what electrical impulses pass through it at a certain time, and what they influence. In this case, a person’s rest is not disturbed, special devices read information from the moment you fall asleep until you wake up. With the help of such studies, the stages of orthodox sleep have been established, which we will consider in more detail.

Slow Phase Stages	How much time does it take from total sleep (in percentage)	What happens in the body
Stage I - nap	12,1	Breathing becomes less deep, but quite loud and frequent, we are in a half-asleep state, the brain is actively working, because at this time you can even find a solution to issues that you could not resolve during the day.
Stage II - sleep spindles	38,1	The pattern of electrical impulses in the brain changes, sleep spindles begin to appear, we fall deeper into sleep, but several times a minute the brain is in a stage of high activity and reacts to the slightest external stimuli, so at this stage you can easily wake up from extraneous sounds.
Stage III - deep sleep	14,2	Sleep spindles are still preserved, but the reaction to external stimuli is dulled, the body enters a “saving” mode, and all its functions slow down.
Stage IV - delta sleep	12,1	The deepest stage of the slow phase - blood circulation slows down, body temperature is minimal, muscles are completely relaxed, there is no reaction to external stimuli, and it is quite difficult to wake a person.

The importance of deep sleep for the body

Many scientists have conducted research into the functions of slow-wave sleep. During the experiments, volunteers were woken up when they were sleeping the deepest. The results showed that the subjects felt muscle pain during awakening, were poorly oriented in space and time, and could not think clearly. Their cognitive and physical performance also deteriorated during the day, even if the rest of the night's rest lasted the required amount of time.

Experts have come to the conclusion that the body perceives the lack of a slow phase as a completely sleepless night. During deep sleep, organs and tissues are restored, as the pituitary gland begins to actively produce somatotropin (growth hormone).

The areas of the brain responsible for storing information also renew their resources. The longer the orthodox phase lasts, the higher the physical and mental indicators become.

However, there are also not very pleasant phenomena in this phase. If a person suffers from enuresis, talks in his sleep, or is a somnambulist, then disorders manifest themselves precisely during delta sleep. This happens for the reason that consciousness is completely switched off, replaced by the subconscious, which we cannot control.

Duration of the slow phase

Every person knows approximately how much time he needs to sleep. But calculating how long the slow phase should have is quite difficult. In general, it takes up from 30 to 70% of the total night's rest and will be individual different people.

In studies conducted at the University of Surrey, it was found that subjects aged 20 to 30 years spent more time in the Orthodox phase than representatives of older age groups. Older people almost always have problems with sleep; their delta phase is much shorter than that of young people.

On average, young people spend 118 minutes per night in slow-wave sleep. However, it was found that in emergency conditions the body can independently extend this time. The Orthodox phase becomes longer if a person suddenly loses weight, so ladies on a diet often experience fatigue and cannot get enough sleep in the same amount of time that they had before body correction. This mechanism is also triggered when there is a malfunction thyroid gland, it is activated by a hormone imbalance.

People who engage in heavy physical labor should have more deep sleep, so athletes rest for 11-12 hours.

Deep phase compensation

Often people who do not have a stable schedule think like this: “Today I’ll work late, and tomorrow I’ll get a good night’s sleep.” If you wake up earlier in the morning, you will create a deficit of REM sleep, which can actually be compensated with a 20-30 minute rest at lunch or the next night. However, such tricks will not work with the slow phase, because our rest begins with it.

Lack of deep sleep gradually accumulates in the body, which negatively affects a person’s ability to work. However, there are others, more serious problems, which you may encounter with chronic sleep deprivation.

First of all, it crashes endocrine system, growth hormone ceases to be produced, causing a person’s stomach to sharply begin to enlarge. Tissues and organs also stop renewing normally. Lack of sleep is a catalyst for aging. Immunity drops sharply, worsens chronic diseases, there is a risk of viral, fungal and bacterial infections.

From here only one conclusion follows: it is unrealistic to sleep through the slow phase on subsequent nights or to “sleep” it in advance, normal functioning The body can only be maintained by following a strict schedule of rest and wakefulness.

Increasing Orthodox phase

If you feel that the slow phase does not have as much time as is needed for normal rest, you can increase it. Most often, such problems appear in people who cannot fall asleep for a long time, because the first sleep cycle contains the longest orthodox phase, and then it becomes less and less long. To get rid of this problem, you should follow these simple recommendations:

Establish a rational sleep-wake schedule.
Go to sleep and wake up at the same time, even on weekends.
Play sports in daytime, but physical activity should not be given to the body 3 hours before a night's rest.
Organize a favorable climate in the relaxation room and a comfortable sleeping place.
Do not drink alcohol, caffeinated drinks, energy drinks, or smoke before going to bed.
Watch your diet - you should not overeat at night, eat chocolate or any other sweets, as these foods have a stimulating effect on the nervous system.

In conclusion

Slow-wave sleep is very important for humans, as it is responsible for restoring physical performance, the immune system and cognitive abilities. It is also necessary for maintaining youth, since it is in the orthodox phase that skin cells are renewed.

You need to fall asleep at 21.00-22.00 in order to get your “portion” of deep sleep and get quality rest during the night. If you follow the schedule, you will notice within 2 weeks how your well-being and appearance will improve.

Sleep is one of the most amazing states, during which organs - and especially the brain - work in a special mode.

From a physiological point of view, sleep is one of the manifestations of the body’s self-regulation, subordinate to the rhythms of life, a deep disconnection of a person’s consciousness from the external environment, necessary to restore the activity of nerve cells.

Thanks to good sleep, memory is strengthened, concentration is maintained, cells are renewed, toxins are removed and fat cells, stress levels are reduced, the psyche is unloaded, melatonin is produced - the sleep hormone, regulator of circadian rhythms, antioxidant and immune protector.

Sleep duration according to age

Sleep serves as protection against hypertension, obesity, division cancer cells and even damage to tooth enamel. If a person does not sleep for more than 2 days, his metabolism will not only slow down, but hallucinations may also begin. Lack of sleep for 8-10 days drives a person crazy.

IN at different ages people need different quantities hours for sleep:

Unborn children sleep the most in the womb: up to 17 hours a day.

Newborn babies sleep about the same amount: 14-16 hours.
Babies between 3 and 11 months of age require 12 to 15 hours of sleep.
At the age of 1-2 years – 11-14 hours.
Preschoolers (3-5 years old) sleep 10-13 hours.
Primary schoolchildren (6-13 years old) – 9-11 hours.
Teenagers need 8-10 hours of rest at night.
Adults (from 18 to 65 years old) – 7-9 hours.
Elderly people over 65 years old – 7-8 hours.

Old people often suffer from insomnia due to ailments and physical inactivity during the day, so they sleep 5-7 hours, which in turn does not have the best impact on their health.

The value of sleep by hour

The value of sleep also depends on the time you go to bed: you can get enough sleep in an hour like a night or not get enough sleep at all. The table shows the phases of a person’s sleep by time of sleep efficiency:

Time	The value of sleep
19-20 hours	7 o'clock
20-21h.	6 hours
21-22 hours	5 o'clock
22-23 hours	4 hours
23-00 h.	3 hours
00-01h.	2 hours
01-02 hours	1 hour
02-03 hours	30 minutes
03-04 hours	15 minutes
04-05 hours	7 minutes
05-06 hours	1 minute

Our ancestors went to bed and got up according to the sun. Modern man does not lie down before an hour nights, the result is chronic fatigue, hypertension, oncology, neuroses.

With the actual value of sleep at least 8 hours, the body regained strength for the next day.

Some southern cultures have a tradition of napping (siesta), and the incidence of stroke and heart attack is noted to be significantly lower there.

Features of awakening in each phase of sleep

Sleep is heterogeneous in its structure; it consists of several phases that have their own psychophysiological characteristics. Each phase has specific manifestations brain activity aimed at restoring different departments brain and body organs.

When it is better for a person to wake up according to the phases of sleep, how easy the awakening will be depends on the phase in which his sleep was interrupted.

During deep delta sleep, awakening is the most difficult due to incomplete neurochemical processes that occur during this stage. And here It is quite easy to wake up during REM sleep, despite the fact that during this period the most vivid, memorable and emotional dreams occur.

However constant shortage REM sleep can be detrimental to mental health. It is this phase that is necessary to restore neural connections between consciousness and subconscious.

Phases of sleep in humans

Features of the brain and its changes electromagnetic waves were studied after the invention of the electroencephalograph. An encephalogram clearly shows how changes in brain rhythms reflect the behavior and state of a sleeping person.

The main stages of sleep - slow and fast. They are uneven in duration. During sleep, the phases alternate, forming 4-5 wave-like cycles from 1.5 to less than 2 hours.

Each cycle consists of 4 phases of slow-wave sleep, associated with a gradual decrease in a person’s activity and immersion in sleep, and one of rapid sleep.

NREM sleep predominates in the initial sleep cycles and gradually decreases, while the duration of REM sleep increases in each cycle. The threshold for a person’s awakening changes from cycle to cycle.

Duration of the cycle from the beginning of slow-wave sleep to the end of fast sleep healthy people is about 100 minutes.

Stage 1 is about 10% of sleep,
2nd – about 50%,
3rd 20-25% and REM sleep - the remaining 15-20%.

Slow (deep) sleep

It is difficult to answer unambiguously how long deep sleep should last, because its duration depends on what sleep cycle a person is in, so in cycles 1-3, the duration of the deep sleep phase can be more than an hour, and with each subsequent cycle the duration of deep sleep is greatly reduced.

The phase of slow, or orthodox, sleep is divided into 4 stages: drowsiness, sleep spindles, delta sleep, deep delta sleep.

Signs of slow-wave sleep are loud and rare breathing, less deep than during wakefulness, a general decrease in temperature, a decrease in muscle activity, smooth eye movements that freeze towards the end of the phase.

In this case, dreams are unemotional or absent; long and slow waves occupy an increasing place on the encephalogram.

It was previously believed that the brain rests at this time, but studies of its activity during sleep have refuted this theory.

Stages of slow-wave sleep

In the formation of slow-wave sleep, the leading role is played by such areas of the brain as the hypothalamus, raphe nuclei, nonspecific nuclei of the thalamus and the Moruzzi inhibitory center.

The main characteristic of slow-wave sleep (aka deep sleep) is anabolism: creation of new cells and cellular structures, tissue restoration; it occurs at rest, under the influence of anabolic hormones (steroids, growth hormone, insulin), proteins and amino acids. Anabolism leads to the accumulation of energy in the body as opposed to catabolism, which consumes it.

The anabolic processes of slow sleep begin at stage 2, when the body completely relaxes and recovery processes become possible.

It has been noticed, by the way, that active physical work during the day prolongs the deep sleep phase.

The onset of falling asleep is regulated by circadian rhythms, and they, in turn, depend on natural light. The approach of darkness serves as a biological signal to reduce daytime activity, and the time for rest begins.

Sleepiness itself precedes falling asleep: a decrease motor activity and level of consciousness, dry mucous membranes, sticking eyelids, yawning, absent-mindedness, decreased sensitivity of the senses, slow heart rate, an irresistible desire to lie down, momentary lapses into sleep. This is how the active production of melatonin manifests itself in the pineal gland.

At this stage, the rhythms of the brain change insignificantly and you can return to wakefulness in a matter of seconds. Subsequent stages of deep sleep demonstrate an increasing loss of consciousness.

Napping, or Non-REM(REM - from English rapid eye movement) - the 1st stage of falling asleep with half-asleep dreams and dream-like visions. Slow eye movements begin, body temperature decreases, heart rate slows down, and on the brain encephalogram, alpha rhythms that accompany wakefulness are replaced by theta rhythms (4-7 Hz), which indicate mental relaxation. In this state, a person often comes to a solution to a problem that he could not find during the day. A person can be brought out of slumber quite easily.
Sleepy spindles – medium depth when consciousness begins to turn off, but the reaction to calling your child’s name or crying remains. The sleeper's body temperature and pulse rate decrease, muscle activity decreases; against the background of theta rhythms, the encephalogram reflects the appearance of sigma rhythms (these are altered alpha rhythms with a frequency of 12-18 Hz). Graphically, they resemble spindles; with each phase they appear less frequently, become wider in amplitude, and fade away.
Delta– without dreams, in which the brain encephalogram shows deep and slow delta waves with a frequency of 1-3 Hz and a gradually decreasing number of spindles. The pulse quickens slightly, the breathing rate increases with a shallow depth, blood pressure decreases, and eye movements slow down even more. There is a blood flow to the muscles and active production of growth hormone, which indicates the restoration of energy costs.
Deep delta sleep- complete immersion of a person into sleep. The phase is characterized by a complete shutdown of consciousness and a slowdown in the rhythm of delta wave oscillations on the encephalogram (less than 1 Hz). There is even no sensitivity to smells. The sleeping person's breathing is rare, irregular and shallow, and there is almost no movement of the eyeballs. This is a phase during which it is very difficult to wake a person. At the same time, he wakes up broken, poorly oriented in the environment and does not remember dreams. It is extremely rare in this phase that a person experiences nightmares, but they do not leave an emotional trace. The last two phases are often combined into one, and together they take 30-40 minutes. The usefulness of this stage of sleep affects the ability to remember information.

Stages of REM sleep

From the 4th stage of sleep, the sleeper briefly returns to the 2nd stage, and then the state of rapid eye movement sleep (REM sleep, or REM sleep) begins. In each subsequent cycle, the duration of REM sleep increases from 15 minutes to an hour, while sleep becomes less and less deep and the person approaches the threshold of awakening.

This phase is also called paradoxical, and here's why. The encephalogram again registers fast alpha waves with low amplitude, as during wakefulness, but at the same time the neurons of the spinal cord are completely turned off to prevent any movement: the human body becomes as relaxed as possible, muscle tone drops to zero, this is especially noticeable in the mouth and neck area .

Motor activity manifests itself only in the appearance of rapid eye movements(REM), during the period of REM sleep a person clearly notices the movement of the pupils under the eyelids, in addition, body temperature rises, activity intensifies of cardio-vascular system and adrenal cortex. Brain temperature also rises and may even slightly exceed its waking level. Breathing becomes either fast or slow, depending on the plot of the dream that the sleeper sees.

Dreams are usually vivid, with meaning and elements of fantasy. If a person is awakened in this phase of sleep, he will be able to remember and tell in detail what he dreamed.

People who are blind from birth do not have REM sleep, and their dreams consist not of visual, but of auditory and tactile sensations.

In this phase, the information received during the day is adjusted between the conscious and subconscious, and the process of distributing the energy accumulated in the slow, anabolic phase takes place.

Experiments on mice confirm that REM sleep is much more important than non-REM sleep. That is why awakening in this phase artificially is unfavorable.

Sequence of sleep stages

The sequence of sleep stages is the same in healthy adults. However, age and various sleep disorders can fundamentally change the picture.

Newborn sleep, for example, consists of more than 50% REM sleep., only by the age of 5 the duration and sequence of stages becomes the same as in adults, and remains in this form until old age.

In older years, the duration of the rapid phase decreases to 17-18%, and the phases of delta sleep may disappear: this is how age-related insomnia manifests itself.

There are people who, as a result of a head or spinal cord injury, cannot sleep fully (their sleep is similar to light and brief oblivion or half-asleep without dreams) or go without sleep at all.

Some people experience numerous and prolonged awakenings, due to which a person is completely sure that he did not sleep a wink during the night. Moreover, each of them can wake up not only during the REM sleep phase.

Narcolepsy and apnia are diseases that demonstrate atypical progression of sleep stages.

In the case of narcolepsy, the patient suddenly enters the REM phase and can fall asleep anywhere and at any time, which can be fatal for him and those around him.

Apnia is characterized by sudden stop breathing in sleep. Among the reasons are a delay in the respiratory impulse coming from the brain to the diaphragm, or excessive relaxation of the muscles of the larynx. A decrease in the level of oxygen in the blood provokes a sharp release of hormones into the blood, and this forces the sleeper to wake up.

There can be up to 100 such attacks per night, and they are not always recognized by the person, but in general the patient does not receive proper rest due to the absence or insufficiency of certain phases of sleep.

If you have apnea, it is very dangerous to use sleeping pills; they can cause death from sleep apnea.

Also, the duration and sequence of sleep stages can be influenced by emotional predisposition. People with “thin skin” and those who are temporarily experiencing difficulties in life have an extended REM phase. And in manic states, the REM stage is reduced to 15-20 minutes throughout the night.

Rules for healthy sleep

Adequate sleep is health strong nerves, good immunity and an optimistic outlook on life. You should not think that time passes in a dream uselessly. Lack of sleep can not only have a detrimental effect on your health, but also cause tragedy..

There are several rules healthy sleep that provide deep sleep at night and, as a result, excellent health and high performance during the day:

Stick to a bedtime and wake-up schedule. It is best to go to bed no later than 11 pm, and all sleep should take at least 8, ideally 9 hours.
Sleep must necessarily cover the period from midnight to five in the morning, during these hours it produces maximum amount melatonin – the hormone of longevity.
You should not eat food 2 hours before bedtime, V as a last resort, drink a glass of warm milk. It is best to avoid alcohol and caffeine in the evening.
An evening walk will help you fall asleep faster.
If you have difficulty falling asleep, it is advisable to take a warm bath before bed with an infusion of soothing herbs (motherwort, oregano, chamomile, lemon balm) and sea salt.
Be sure to ventilate the room before going to bed. You can sleep with the window slightly open and the door closed, or open the window in the next room (or in the kitchen) and the door. To avoid catching a cold, it is better to sleep in socks. The temperature in the bedroom should not fall below +18 C.
It is healthier to sleep on a flat and hard surface, and use a bolster instead of a pillow.
Stomach position is the worst position for sleeping, the position on your back is most beneficial.
After waking up, a small exercise stress: exercise or jogging, and, if possible, swimming.

Scientists have long proven that good sleep, which includes two main phases - slow and fast - is extremely important for human health and well-being. And this fact must be taken into account when creating a daily routine. There is an old folk saying that states that “the morning is wiser than the evening.” And indeed, to accept important and complex solutions It's much easier in the morning than at night. In addition, each of us has noticed how lack of sleep affects well-being and performance. A sleepless night may lead not only to a sharp decrease in mental activity, but also headache, weakness, weakness and other unpleasant symptoms.

Physiology of sleep

The human body is designed in such a way that all processes occurring in it are tied to a certain daily time and largely depend on the change of day and night. Sleep and wakefulness constantly alternate between each other and occur at approximately the same time. And if normal rhythm sleep-wakefulness is suddenly disrupted, this has the most negative impact on the work of various human systems and organs. From chronic lack of sleep First of all, the nervous and immune system, which can lead to the gradual disabling of the entire organism.

Wakefulness and sleep are two opposite and, at the same time, interconnected states. When a person is awake, he actively interacts with environment: eats, exchanges information, and so on. During sleep, on the contrary, there is an almost complete disconnection from the outside world, although important processes in the body itself do not stop. It is estimated that sleep and wakefulness are in a 1:3 ratio, and any deviation from this norm is dangerous to health.

Scientists have been able to record changes that occur in the human brain during sleep using a research method such as electroencephalography. It allows you to make a graphic recording in the form of waves, the decoding of which provides information about the quality of sleep and the duration of its different phases. This method is mainly used for diagnosis various violations sleep and to determine their degree negative influence on the body.

When the mechanism that regulates the frequency of sleep and wakefulness is disrupted, various pathological conditions, such as narcolepsy (an irresistible desire to fall asleep that occurs during the day), as well as hypersomnia (an exaggerated need for sleep when a person sleeps much more than normal).

Sleep is characterized by a quality called cyclicity. Moreover, each cycle lasts an hour and a half on average and consists of two phases - slow and fast. For a person to get enough sleep, four to five such cycles must pass. It turns out that you need to sleep at least eight hours a day.

The main differences between the phases are:

Duration The predominant phase is the slow phase. It takes up approximately 80% of the time of the entire sleep process and, in turn, is divided into four stages. The fast phase takes significantly less time, and its duration increases in the morning, closer to awakening. Purpose The purpose of sleep phases is different. During the slow phase they are restored internal organs, the body grows and develops. The fast phase is needed to activate and regulate the nervous system, to organize and process accumulated information. During REM sleep, children develop the most important mental functions - which is why in childhood we so often see vivid, memorable dreams.

Brain activity The differences between the slow and fast phases in terms of brain activity are very interesting. If during slow-wave sleep all processes in the brain slow down significantly, then in the REM sleep phase they, on the contrary, are extremely activated. That is, a person is sleeping, and his brain is actively working at this time - that’s why REM sleep is also called paradoxical. Dreams People see dreams throughout the entire cycle, but those dreams that occur during the fast phase are better remembered. The dynamics of dreams also strongly depend on the phase - the slow phase is characterized by restrained dreams, during the fast phase they are more vivid and emotional. Therefore, it is morning dreams that most often remain in memory after waking up.

How does the sleep process proceed?

When a person becomes drowsy and falls asleep, the first stage of non-REM sleep begins, lasting a maximum of ten minutes. Then, as the second, third and fourth stages occur, sleep becomes deeper - all this lasts approximately 1 hour 20 minutes. It is the fourth stage of the first phase that is characterized by such well-known phenomena as sleepwalking, talking in sleep, nightmares, and childhood enuresis.

Then, for a few minutes, there is a return to the third and second stages of slow-wave sleep, after which the fast phase begins, the duration of which in the first cycle does not exceed five minutes. At this point, the first cycle ends and the second cycle begins, in which all phases and stages are repeated in the same sequence. In total, four or five such cycles change per night, and each time the REM sleep phase becomes longer and longer.

In the last cycle, the slow phase may be exceptionally short, while the fast phase is predominant. And it’s not for nothing that nature intended it this way. The fact is that waking up during REM sleep is very easy. But if a person is woken up when slow-wave sleep is in full swing, he will feel exhausted and sleep-deprived for a long time - one can say about him that he “got off on the wrong foot.”

NREM sleep phase (4 stages)

Stage	Description	Duration
Nap	The pulse and breathing slow down, the eyes move slowly under closed eyelids. Consciousness begins to float away, but the mind still continues to work, so at this stage people often come to interesting ideas and solutions. In a state of drowsiness, a person wakes up relatively easily.	No more than 5-10 minutes.
Sleep spindles	The name of the second stage of slow-wave sleep is associated with the encephalogram graph. During this period, the human body relaxes, but the brain still remains sensitive to everything that happens around it and reacts to the words and sounds heard.	Approximately 20 minutes.
Delta sleep	This stage precedes deep sleep. Characterized by a slight increase in heart rate, breathing is also rapid, but shallow. Blood pressure drops, eye movements become even slower. At the same time, active production of growth hormone is observed, blood flows to the muscles - thus the body restores energy costs.	About 15 minutes.
Deep dream	At this stage, consciousness is almost completely turned off, the eyes stop moving, breathing becomes slow and shallow. A person sees dreams of neutral, calm content, which are almost never remembered. Waking up during deep sleep can only be forced and occurs with great difficulty. A person awakened at this stage feels overwhelmed and lethargic.	From 30 to 40 minutes.

REM sleep phase

When a person enters the REM phase of sleep, it can be seen even from the outside. He starts to move actively eyeballs, breathing either quickens or slows down, facial movements may be noticeable. The devices record a slight increase in body and brain temperature, increased cardiovascular activity. During this phase, the process of exchanging information accumulated during wakefulness between consciousness and subconscious occurs, and the energy that the body managed to accumulate during slow sleep is distributed. A person sees colorful dreams that he can remember and retell after he wakes up. Waking up during REM sleep is the easiest and fastest.

How much sleep do you need to get enough sleep?

According to scientists, a person needs to sleep from 8 to 10 hours a day, which equals 4-6 sleep cycles. It should be borne in mind that the duration of the sleep cycle varies from person to person and, depending on the individual characteristics of the nervous system, can vary from 1.5 to 2 hours. And so that the body receives good rest, there should be at least 4-5 such complete cycles. How much sleep a person should have is largely determined by his age.

Here are the approximate sleep norms for different age groups:

Unborn babies in the womb sleep the longest - about 17 hours a day.
Newborn babies spend 14 to 16 hours sleeping.
Babies aged 3 to 11 months need to sleep 12-15 hours.
One- and two-year-old children sleep 11-14 hours a day.
It is advisable for preschoolers to sleep at least 10-13 hours.
The body of primary school children under 13 years of age requires 10 hours of rest at night.
Teenagers are recommended to sleep between 8 and 10 hours.
Sleep duration of an adult from 18 to 65 years, depending on personal characteristics body, is 7-9 hours.
The need of people after 65 years decreases slightly - they need to sleep from 7 to 8 hours.

How to sleep less and get enough sleep

The quality of sleep is very dependent on what time a person goes to bed. Sleeping until midnight from 19.00 to 24.00 is extremely beneficial. People who are accustomed to falling asleep early feel refreshed and well-rested, even if they get up at dawn. In this case, a person can sleep less, but still get enough sleep. And the trick is that the value of sleep in a certain period of time is different.

Sleep value table by hour

Sleep period	The value of rest
19.00 — 20.00	7 hours
20.00 — 21.00	6 hours
21.00 — 22.00	5 hours
22.00 — 23.00	4 hours
23.00 — 24.00	3 hours
24.00 — 01.00	2 hours
01.00 — 02.00	1 hour
02.00 — 03.00	30 min
03.00 — 04.00	15 minutes
04.00 — 05.00	7 min
05.00 — 06.00	1 min

What time is best to get up in the morning?

It is believed that the best time to wake up is from 4 to 6 am. People who rise with the sun are not afraid of fatigue, and they manage to do a lot during the day. But, of course, in order to get up early, you need to develop the habit of going to bed early. In addition, people have different biological rhythms. As you know, people are divided into “night owls” and “larks”. And if a person is a night owl, then it is better for him to wake up around 8-9 in the morning.

How to correctly calculate your wake-up time

It is very difficult to independently calculate the time for which you need to set an alarm clock in order to wake up in the REM sleep phase. As mentioned above, each person's sleep phases have an individual duration. Therefore, before carrying out such calculations, you must first contact medical Center so that specialists can determine your personal sleep rhythm using special instruments.

Although it is possible to calculate the approximate time When is the best time to wake up? To do this you need to take average duration slow sleep phase (120 minutes), as well as the average duration of fast sleep (20 minutes). Then you should count 5 such periods from the moment you go to bed - this is the time you set the alarm clock. For example, if you fall asleep at 23:00, then the best time to wake up for you will be from 7:20 to 7:40 in the morning. If you decide to sleep longer, for example on Sunday, then the time to get up correctly will be between 09:00 and 09:20.

The importance of sleep for the body

The main purpose of sleep is to allow the body to rest and recover. Prolonged insomnia is fraught with serious health problems. Animal experiments have shown that complete absence sleep after a certain time causes hemorrhages in the brain. People who are chronically sleep deprived soon experience increased fatigue, and then problems with the cardiovascular system join.
Sleep affects metabolic processes in the body. While a person is in slow-wave sleep, growth hormone is produced, without which protein synthesis cannot occur - therefore, lack of sleep is especially dangerous for children. In people who lack sleep, the cleansing and restoration processes in the body are also disrupted, since during sleep, organ cells are actively supplied with oxygen, and the work of the liver and kidneys, which are responsible for neutralizing and removing harmful substances, is activated.
During the fast phase, the distribution, processing and assimilation of accumulated information occurs. By the way, as it turned out, it is impossible to learn and remember anything during sleep (the method of teaching foreign languages to sleeping people has not justified itself), but the information that entered the brain immediately before sleep is indeed better remembered.
REM sleep promotes the activation of all neurohumoral processes - the human nervous system adjusts to active work. It has been noticed that a lot of nervous diseases appear from lack of sleep.

The effect of sleep on the cardiovascular system

Many of us are accustomed to regularly invigorate ourselves with tonic drinks - strong tea, coffee. Yes, this way you can really cheer yourself up for a short period of time. But then, when caffeine stops working, the person feels even more tired, drowsiness and weakness appear. Therefore, there is nothing better for cheerfulness than normal sleep. People who systematically cut down their sleep time, thereby force their body to work under overload and lead it to exhaustion, as a result of which such problems arise. serious illnesses like ischemia, chronic, and so on.

The effect of sleep on appearance

Medical scientists unanimously claim that lack of sleep provokes oxygen deficiency in the body and inevitably leads to early aging and significant deterioration. appearance. A well-rested person, as a rule, can boast not only of vigor, but also a fresh appearance, good color faces. By the way, metabolic disorders, which can lead to chronic insomnia, often entail increased appetite and... Therefore, athletes and actors, for whom it is vital to always be in good physical fitness, strictly adhere to the sleep-wake schedule.

Sleep and human behavior

It has been noticed that in people who do not get enough sleep, such negative character traits as capriciousness, short temper, irritability, and aggressiveness become more acute. And all because their nervous system is not ready for stress and is constantly on edge. But among those who get good sleep, it prevails great mood and full psychological readiness to overcome life's problems. Therefore, if your work involves night shifts, be sure to compensate for the lack of sleep during the day. Drivers should never get enough sleep. Great amount accidents occurred due to the fact that a sleep-deprived driver was distracted or fell asleep at the wheel.

And finally, we should remember one more function of sleep - through dreams, our subconscious often sends us hints and insights that help us solve important life problems.