REM and NREM sleep. What's better than different stages of sleep?

(rapid) sleep was so carried away by research into its paradoxes that no attention was paid to the slow phase of sleep. NREM sleep was perceived as a natural background for paradoxical sleep.

However, this phase declared itself and made us think about the role of slow-wave sleep in the vital processes of the human body.

During another experiment on deprivation of pre-dawn REM sleep for several nights, the experimenters were surprised that on the recovery night the deepest stage of slow-wave sleep, delta sleep, wanted to take revenge.

Means, NREM sleep and REM sleep are inseparable and are continuations of each other:

• the synthesis of norepinephrine, a mediator of paradoxical sleep, occurs in slow-wave sleep;
• with the destruction of the raphe nuclei of the brain stem, which contain serotonin, both stages of sleep are disrupted.

Having many differences, they belong to a single balanced system; they are connected by chemical, physiological, functional and mental processes.

Napping has a rhythm similar to REM sleep. and is often filled with half-thoughts, and occasionally with real dreams.

two or three nights spent accompanied by sound stimulation reduces physical and mental performance, gives a feeling of fatigue, and slows down the speed of reactions.

This result suggests the dominant role of delta sleep for physical and emotional recovery.

At first glance, the activity of galvanic skin processes and the nightmares that occur during this stage indicate not the accumulation, but the expenditure of energy.

However, behind the external picture of energy consumption lie recovery processes. They explain the revival of vegetative activity; it occurs in REM sleep.

Deep mental work takes place, in which (as during wakefulness) the scouts of the mind take part - emotions that give an unconscious first assessment to any impression, any thought or memory that comes to mind.

Where there are emotions, GSR is always present.

The effect of additional physical activity on slow-wave sleep

Young men who were far from sports and engaged in mental work exercised on a bicycle ergometer for 120 minutes. Daytime loads had almost no effect on the structure of night sleep. Evening loads had a noticeable effect.

Every night we all go through phases of sleep: rapid and slow sleep. Physiologically, sleep is a complex of 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 human dreams and their influence on his physiology and psyche in any way. Initially, they were studied based on a purely physical description of the processes - it was possible to determine the sleeper’s pulse, his blood pressure and his body temperature. But there was no talk of assessing the influence of sleep on mental and physical activity.

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 more important for a person than nutrition. A person deprived of sleep for only two or three days becomes irritable, loses emotional stability, and begins to experience memory loss. Against the background of fatigue and mental retardation due to lack of sleep, a person falls into a 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. If you interrupt the night cycle at a stage when only one of the cycles is completed, the body will not receive proper rest. 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.

In fact, a full sleep 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 a major role in strengthening joints, blood vessels and skin;
• The body absorbs calcium, which is necessary for bone and dental tissue.

These processes take quite a long time, so to feel 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. Waking up is a very difficult time and leaves unpleasant sensations for quite a 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 who falls into a state of drowsiness, despite the decrease in physiological processes, continues to work with the brain and he thinks about and improves 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, and the optimal options are selected. 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. Its distinctive feature is the 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 who is in this stage: even loud sounds, brakes and fairly strong pain are not able 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 wake a person during this stage, the rise will be extremely difficult and the final restoration of the body may not occur until the next period of sleep.

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:

1. Increased breathing and heart rate.
2. Frequent arrhythmias in the heart.
3. Decreased muscle tone.
4. A significant decrease in the activity of the muscles of the neck and diaphragm.
5. Increased motor activity of the eyeballs with closed eyelids.
6. 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 here that the exchange of data between consciousness and subconscious takes place, and what was thought about during dozing again enters consciousness, but now supplemented by various options that can 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, a significant change in hormonal levels is observed. According to researchers, it is REM sleep that promotes daily reconfiguration of the endocrine system.

Thus, REM sleep seems to sum up all the mental activity of the brain for the whole day. Rest at this stage is necessary for a person so that he can adapt to possible options for the development 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 mental disorders. 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, a minor 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 of the 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 of complete changes of all stages occur. 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 restoration of normal organ functions and the appearance of clarity of consciousness occurs.

The main differences between NREM and REM sleep

NREM and REM sleep serve 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 of the pituitary gland. Accelerated synthesis of most hormones	Inhibition of spinal cord reflexes. 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 of a calm nature. 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. Severe waking up due to incomplete 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.

Slow sleep regulates the internal rhythms of brain areas and structures, while fast sleep promotes 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. Standing up during the active fast phase is 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:

1. Light from the window.
2. Sounds from the street or music.
3. 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, the body can “drag” 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 occurred ahead of schedule, then you can fall asleep again and wake up in a deep stage, ruining your entire 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, recently “smart alarm clocks” have begun to appear on sale, which are connected using 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!

The problem of lack of sleep has always been relevant. Each of us has repeatedly woken up far from being at our best, gone to work or school, barely opening our eyes. Sometimes the reasons for such a state are obvious - the day before there was a holiday, the boss was busy with work until late at night, he was sitting on notes before the exam. But what if there were no such reasons? It seems like you went to bed early, but in the morning you still feel weak and tired.

There is an explanation for this phenomenon, and, most importantly, there is an opportunity to correct the situation. All you need to do is simply calculate in which phase of sleep it is better to wake up. This article will tell you how realistic this is.

Sleep as a process still remains a mysterious, inexplicable phenomenon. But scientists unanimously confirm that it is important and necessary for health and normal functioning. Numerous experiments have repeatedly proven this.

Everyone can feel how harmful a lack of a good night's rest can be. Sometimes it is enough to spend just one sleepless night to realize how bad a sleep-deprived person feels.

Sleep gives the body the opportunity to rest and recover. Some people refuse this for various reasons: some need to work night shifts, others are too dependent on the Internet, smartphone or computer games. Periodic lack of sleep is fraught with a number of unpleasant consequences, for example:

• dizziness and migraine;
• depressed and irritable mood;
• drowsiness, lethargy, low work efficiency;
• inability to concentrate, decreased mental abilities.

These problems go away as soon as a person gets the opportunity to sleep well. It is important to remember that any lack of sleep negatively affects the body and its activities. Chronic lack of sleep threatens great difficulties. Here are just a few pathologies, the cause or symptom of which is the lack of a normal sleep pattern:

• papilledema, glaucoma;
• hypertension;
• vegetative-vascular dystonia;
• diabetes;
• obesity;
• premature aging.

Attention! Leading a nocturnal lifestyle with a lack of healthy, full-fledged sleep negatively affects the functioning of organs and reduces the production of essential hormones - serotonin and melatonin. A constant lack of rest disrupts the psyche, causes depressive and nervous disorders, and hallucinations. In men, lack of sleep can cause decreased libido and impotence; in women, excess weight and wrinkles appear.

The best sleep phase for waking up

Unfortunately, even for those whose lives extend beyond work and home, lack of sleep is a common problem. Scientists believe this can be avoided. In their opinion, it is necessary to wake up at the right moment: the phases of sleep will tell you how to get enough sleep. But first things first.

Ideas about sleep cycles

In the course of numerous experiments studying sleep as a process, researchers were able to find out that the brain continues its work at night. This was confirmed by the results of the electroencephalogram.

The results showed that night rest is accompanied by a change of stages that repeat in a circle. Over the course of several hours, on average, up to five such changes occur. Each cycle was divided into two phases - slow and fast sleep. Both have their own characteristics. The duration of one circle for a healthy adult is about 1.5-2 hours.

Description of the stages of the slow phase

The first phase of the cycle, from which a person’s sleep begins, takes up approximately 70% of the total time. It has four stages:

Interesting to know! The slow phase of sleep is the time when the human body recovers. The heartbeat is slow, body temperature drops by about 1 degree, pulse rate and blood pressure are reduced. As dawn approaches, this part of the cycle becomes shorter and shorter. After the slow phase comes the fast phase, also known as the paradoxical phase.

Characteristics of the fast phase

The paradoxical phase is characterized by the presence of vivid dreams. Physiologically, the sleep stage is manifested in brain activity - indicators reach the level of wakefulness. There is also sleep paralysis (the muscles of the body are relaxed to the limit) and rapid eye movement, as if the sleeper is watching a movie behind closed eyelids (or maybe even participating in it).

If the previous phase is necessary for the body, then this phase is necessary for consciousness. It is believed that in a dream the information accumulated during the day is processed: thoughts, plans, desires, memories, etc.

Awakening in different phases: distinctive features

Psychophysiological processes that occur at different stages make night rest heterogeneous. Because of this, a person will either awaken without problems or “rise from the dead.”

Waking up in the paradoxical phase, a person can remember what he dreamed. Vivid images and visions can leave impressions for the whole day; it is easy to wake up during this period.

It is also important to consider the conditions for going to bed and the load received during the day. Naturally, someone who has been doing hard physical labor all day will sleep more soundly than someone who has not left the computer.

It is important to know! The slow phase is characterized by deep immersion in sleep. If you wake up in this phase, then only in its second stage - it will not be so painful. And the most difficult awakening is at the fourth stage of the slow phase: it is almost impossible to navigate the environment, the reaction is inhibited. You won't want to get out of bed at all. In general, the condition resembles very strong intoxication.

The best time to interrupt sleep

It is believed that it is easiest to wake up during REM sleep, when a person is dreaming about something. However, experts do not recommend getting up in this phase too often. Its lack is fraught with mental disorders.

It’s a little harder, but just as realistic, to wake up in the second stage of slow-wave sleep. Awakening is possible, since at this stage a person’s hearing becomes more acute.

Calculation of the duration of sleep phases

In the course of research, scientists have suggested that the ideal time to wake up can be calculated. The basis is the required number of hours for proper rest, as well as certain conditions: during the day the person was not overly stressed physically and mentally, went to bed for natural reasons, did not wake up to an alarm clock, easily and naturally.

Interesting to know! If we take into account that the required time to get enough sleep is 8 hours, and one cycle takes about 1.5-2 hours, you can make a calculation - determine the moment of the onset of the paradoxical phase, in which awakening will be as simple and pleasant as possible. It is important to remember that adequate sleep requires at least four cycle changes. There are many graphs and tables of human sleep phases by time on the Internet, the most obvious example is given below.

It is possible to find out when it is better to wake up by counting the phases of sleep, but it is impossible to guarantee 100% that waking up in the fast phase will actually be effective. Night rest is purely individual for each person, therefore any attempt to find out the most suitable time to wake up, as well as the number of hours necessary for complete relaxation and restoration of the body, will be in the nature of an experiment.

Advice! You can use a calculator provided by one of the Internet sites. This calculation is the fastest: you need to specify the time to fall asleep and wait for the result displayed on the screen.

Rules to help a person get a good night's sleep

Before determining when is the best time to wake up, you need to take care of the quality conditions for normal rest. A slight morning awakening requires preliminary sound, healthy sleep.

1. It is not recommended to drink alcohol and a lot of fatty foods before going to bed. A couple of hours before night it is better not to eat or drink anything at all.
2. A comfortable sleeping place helps you fall asleep quickly. Rough sheets, an unseasonably warm blanket, blocked access to fresh air - all this is an unnecessary reason for waking up in the middle of the night.
3. No gadgets in bed. Going to bed should resemble a ritual: brush your teeth and wash your face, prepare your things for tomorrow, open the window, go to bed, take a book.
4. Good sleep is also influenced by how much a person loads himself during the day. It is necessary to correctly calculate your working abilities and capabilities, not to jump over your head, but also not to be lazy.
5. Minimize light sources - sometimes even the flickering light of a laptop indicator can prevent a person from falling asleep.

Easy awakening in the rapid phase of sleep, which was discussed above, is possible only with normal, full sleep, consisting of at least four cycles. You shouldn’t consider yourself a superman trying to get enough sleep in a couple of hours - few people succeeded, and it was caused more by a structural DNA disorder than by willpower or self-discipline.

Conclusion

Sleep remains a mysterious and difficult to explain phenomenon. Many popular science magazines, documentary television programs and articles on the Internet talk about new discoveries in this area. Despite numerous experiments, there are still fewer hard facts than guesses. Calculating sleep stages is just another page in this story.

Full functioning depends on good, sound sleep. No table, no calculations will help if there are problems or deviations in night rest. Before determining the phase in which you can wake up, make sure that you fall asleep normally. A short sleep will not bring satisfaction to either the soul or the body.

Contents of the article

Sleep is a cycle of phases that replace one another. During this period, a sleeping person encounters dreams, restores strength, normalizes thinking, and gains a unique experience. Typically, the structure within which the phase changes occur is the same for all nights, and the cycle can be repeated up to five times. Deep sleep is an element of the non-REM sleep phase, which has a maximum duration compared to REM sleep. It is often called orthodox. What is the deep phase, what is the norm of deep sleep, and how much should it constitute of the total amount of time spent in the “embraces of Morpheus”, we will consider in the article.

Classic sleep structure

The sleep cycle starts immediately after falling asleep, and its duration is 80-90 minutes. A division into the following stages is observed.

• First stage. The person is in a doze with half-asleep reverie. It causes hallucinogenic thoughts and images that pass over time. Essentially, a slow and gradual descent into deep sleep begins.
• Second stage. It is called shallow or light. The heart rate becomes slower and the temperature becomes lower. The muscles relax, the brain falls asleep. In a healthy person, it accounts for about 55% of the time per night.
• Third stage. This is a slow mode that takes less than half of the entire process. Dreams and images may appear.
• Fourth stage. This is the deepest phase during which slow delta sleep occurs. A characteristic feature of this stage is the difficulty of waking up a sleeping person. About 80% of all dreams are observed. It is this stage that is characterized by the likelihood of attacks of sleepwalking, nightmares, and conversations. But the point is that a person does not remember these moments. This process takes about 15% of the time.
• Fifth stage. It is fast and occurs differently for each person. It occurs after a slow cycle and is called paradoxical sleep. Its duration is about 10 minutes. Brain activity at this stage has many similarities with wakefulness, however, the person maintains a motionless position. If you wake up the sleeper at this stage, he will remember his dreams vividly and clearly.

These are the stages of the entire cycle. Each of them has its own norms and characteristics of its course. We will consider the stage of deep sleep.

Deep sleep stage

An accurate division of all stages can be carried out directly using an electroencephalogram, which determines the indicators of past sleep. This measure records brain activity throughout sleep and acts as a state-of-the-art study. It helps to reflect the state of activation and is more like the first stage EEG. The first manifestation of deep sleep starts an hour and a half after falling asleep and lasts about 10 minutes. As the process progresses, the duration of subsequent episodes of deep sleep will increase and in the morning an indicator of several tens of minutes is observed. From one cycle to another, the stage of REM sleep becomes longer, and the depth decreases.

How easy it is to find it

Example of a sleep tracker bracelet

If a person is faced with the task of simply “evening out” his own sleep patterns, he can use special bracelets. What it is and how to choose the right one can be found in ours. Of course, they cannot determine the phase in which the body is, but they are able to record movements made in sleep. In this regard, they will help to separate into two phases - when the individual is tossing and turning or is stationary. The information is displayed in the form of a fence, a special schedule. And the main function of the bracelet is as an alarm clock that wakes up a person when he is in the fast phase.

Stage duration

The norm of sleep and its mode is a purely individual indicator. For each person, the amount of time needed to sleep to maintain a normal state of mind and health is different. There are people who only need a couple of hours, as well as those who sleep for 10 hours or more. But, as practice shows, if an ordinary person has to reduce his norm, then, most likely, after waking up he will be tired and aggressive. However, the value of an adult's deep sleep norm plays an important role. This is evidenced by numerous results of experiments.

It is impossible to imagine any human body without sleep. Sleep is a natural physiological process that everyone needs. How many hours does an adult need to sleep on average to feel great and work productively? So, on the agenda is sleep, sleep norms and its effect on the body.

The dangers of lack of sleep

Lack of sleep is an insidious thing that negatively affects not only your mood and ability to work, but also your overall health. Here are a few dangerous consequences that develop as a result of chronic lack of sleep:

1. Impaired cognitive functions - a broad term that refers to a decrease in mental activity, as a result - deterioration of memory and attention. Most emergency situations, both on the road, at work and at home, according to statistics, occur precisely during such periods when a person is not able to fully control the events occurring around him.
2. Weakened immunity - lack of sleep inevitably leads to vulnerability of the immune system, greatly increasing the risk of getting sick. This fact is due to the fact that in the absence of proper sleep, the cytokine protein (the body’s natural defense against viruses and infections), necessary for the correct functioning of organs and systems, is not produced. Sleep heals - you shouldn’t forget about it.
3. Eating disorders - frequent lack of sleep leads to problems with excess weight. All this is due to the stimulation of the production of the hunger hormone - ghrelin. A tired brain that does not receive rest requires “feeding,” resulting in a constant feeling of malnutrition and extra pounds around the waist.
4. Decreased productivity - lack of sleep makes a person lazy, slow, and lacking initiative. Any work is done much more slowly, taking even more strength and energy. As a result, a person loses the desire to motivate, develop himself and his business.
5. Bad mood - a sleep-deprived person is more susceptible to the negative influence of the environment: he is quick-tempered, touchy and irritable.
6. Poor appearance - bruises and bags under the eyes - is another unpleasant “bonus” of lack of sleep.
7. Risk of developing serious diseases - systematic lack of adequate sleep increases the risk of developing diabetes, vascular and heart diseases.

Sleep phases

There are two types of sleep: slow and fast. It is known that every day during one sleep cycle a person is in these two phases: slow sleep lasts on average an hour and a half, fast sleep - from 2 to 30 minutes.

Let's take a closer look at this classification:

• Slow sleep.

Coming after falling asleep, slow wave sleep includes 5 stages:

1. Zero - the appearance of drowsiness, slowing of the movement of the eyeballs, decline in mental activity. Electroencephalography (EEG, a research method that reflects changes in the functioning of the cerebral cortex) registers the presence of alpha waves.
2. The first is a decrease in attention to irritating factors and falling asleep.
3. The second is the onset of shallow sleep. The EEG notes sigma waves and “sleep spindles” (a state in which consciousness is dulled).
4. The third and fourth phases are the so-called “deep” sleep. The EEG records the appearance of delta waves: almost all dreams that occur occur during these phases. The stage is characterized by dreams. The fourth stage “transitions” into REM sleep.

• Quick sleep.

The REM stage of sleep replaces slow sleep. On average, its duration is 10-20 minutes. At this time, a sleeping person experiences an increase in blood pressure and body temperature, an increase in heart rate, and an acceleration in the movement of the eyeballs. Only the muscles responsible for breathing and heartbeat remain active. In addition, REM sleep is accompanied by active brain activity, the occurrence of dreams is another feature.

How much sleep does a child need?

So, there is a distinction between slow and fast sleep. Sleep standards exist for every age. The younger you are, the more sleep your body needs to maintain normal functioning. Let's consider sleep standards for children and adults separately.

1. Children (0 to 3 years old).

The table of sleep norms will clearly show how many hours a day a child needs to sleep:

Child's age	Daytime nap	Night sleep	Daily sleep norm
Newborn	The intervals of wakefulness are minimal, sleep lasts on average 1-3 hours	Without a break, a newborn is able to sleep 5-6 hours, sleep is interrupted only by eating	Sleep norms for a newborn are 16-19 hours a day. Until the age of 1 month, a child’s life passes almost in sleep (about 20 hours)
	On average, a child should sleep 4-5 times, which is a total of 5-7 hours	On average 8-11 hours, waking up for feeding is acceptable	The norm of sleep hours decreases slightly, amounts to 14-17 hours
	3-4 sleeps, 4-6 hours in total	10-12 hours, with breaks for feeding	14-17 hours
	The number of times a child “agrees” to sleep at this age is about 2-3; in total, 2 to 4 hours are allocated for daytime sleep	10-12 hours	Total about 15 hours a day
	2 naps, total 2-3 hours	10-12 hours	12-15 hours
	One or 2 naps, a total of 2-3 hours per daytime nap	The norm for nightly sleep is still 10-12 hours	12-14 hours a day
	One nap, lasting from 1 to 3 hours	10-11 o'clock	11-14 hours
	At this age, a large number of children go without sleep. In this case, during the night the child must “make up” for lost daytime hours; 1 nap for 1-2 hours	10-11 o'clock	11-13 hours

2. Children (4-17 years old).

What should sleep be like for children over 3 years old? Sleep standards for children over 4 years old are somewhat different from those discussed above. The fact is that by the age of 4, a grown-up body is able to do without daytime rest. But, as in the case of a three-year-old child, the night's sleep should be complete. So, children under 10 years old should sleep at least 10 hours at night, at an older age - at least 8.

How much sleep does an adult need?

Now let's look at an adult's dream. Sleep norms in this case are no longer so different depending on age, however, they have different indicators. A healthy adult from 18 to 64 years old needs at least 7-9 hours of proper rest.

For older people over the age of 65, the sleep norm is slightly reduced: to keep the body in good shape and stay in an excellent mood, 7-8 hours of nightly dreams are needed.

Norm of deep sleep

In order to rest overnight from the past day and properly prepare mentally and physically for the day ahead, it is necessary not only to “sleep” the required number of hours, but to spend a sufficient time in the deep sleep phase. So, for an adult, this period normally occupies from 30 to 70% of total sleep.

There are several rules for increasing the percentage of stay in the deep sleep phase:

• Maintaining a routine - it is recommended to go to bed and get up at the same time.
• Physical stress on the body for 2-3 hours of falling asleep.
• Ignoring bad habits and overeating.
• Maintaining an optimal climate in the bedroom (humidity 60-70%, air temperature 18-20°C).

With age, the time people spend in the long sleep phase decreases noticeably. Due to this, the aging process accelerates.

The secret to performance

In order to feel great, keep up with work and get up with ease every morning, you need little: you just need to follow a routine, stay in the fresh air as long and often as possible and, most importantly, get enough sleep. Then any seemingly insurmountable obstacle will be manageable, and everyday trips to work will not be a burden. Be in harmony with yourself and others!