The processes that occur with a person during sleep

Процессы, которые происходят с человеком во время сна

Sleep (Latin somnus) is a natural physiological process of being in a state with a minimum level of cerebral activity and a reduced response to the surrounding world, inherent in mammals, birds, fish and some other animals, including insects (eg, fruit fly). In addition, the word "dream" refers to the sequence of images (formed during the so-called "fast sleep" phase) that a person can remember (see also the dream). Physiologically, ordinary sleep differs from other similar states - anabiosis (so-called "hibernation" in animals), hypnotic sleep, coma, fainting, lethargic sleep.

1. The temperature of the body falls

Процессы, которые происходят с человеком во время сна

Since most of the muscles become inactive during sleep, the body burns fewer calories than during the day, and body temperature drops. Scientists found that body temperature is usually the lowest around 2:30 am.

2. Eyes are moving

Процессы, которые происходят с человеком во время сна

Although the eyes in the dream are closed for centuries, they move under them. In fact, this movement even differs depending on the specific stages of sleep.

3. The body twitches

Процессы, которые происходят с человеком во время сна

Sharp twitchings and jerks are mainly associated with the first stage of sleep. They are usually harmless, but they can be strong enough to actually wake a person.

4. Muscles relaxed

Процессы, которые происходят с человеком во время сна

There is a good reason why most of the muscles during sleep are debunked. If they were active, then a person could move during sleep, which would be extremely dangerous.

5. The skin is restored

Процессы, которые происходят с человеком во время сна

The upper layer of the skin consists of tightly packed dead cells that are constantly discarded during the day. During sleep, the metabolic rate of the skin accelerates and in many cells of the body, an increase in activity and a decrease in the breakdown of proteins begin. Since proteins are necessary for growth and restoration of damage from such factors as ultraviolet radiation, deep sleep has a beneficial effect on the skin.

6. The brain forgets useless information

Процессы, которые происходят с человеком во время сна

People perceive throughout the day an insane amount of information. If they remembered it all, they would soon go mad. That's why at night the brain sorts information and forgets about unnecessary.

7. The throat narrows

Процессы, которые происходят с человеком во время сна

Unlike most other muscles, the throat muscles do not paralyze during sleep, as they are necessary to breathe. Nevertheless, during sleep they relax, resulting in a narrowing of the throat. It can also cause snoring.

8. The body produces hormones

Процессы, которые происходят с человеком во время сна

During the slow sleep stage, the human body produces hormones that stimulate growth, cell multiplication and cell regeneration. This is an important regulator of the immune system.

9. The immune system is at a record high level

Процессы, которые происходят с человеком во время сна

It was proved that sleep deprivation negatively affects the immune system. One study showed that people who received flu shots and were deprived of sleep the next night did not produce the antibodies needed to protect themselves from the flu. Therefore, if a person has noticed the first signs of infection, he should sleep.

10. Weight Loss

Процессы, которые происходят с человеком во время сна

During sleep, a person loses water by sweating and exhaling moist air. This also happens during the day, but eating and drinking negate any weight loss. Therefore, for any diet requires a good and long sleep.

11. Dry mouth

Процессы, которые происходят с человеком во время сна

Since saliva is mainly needed for food, and a person does not eat during sleep, the amount of saliva released decreases at night. Consequently, the mouth dries up, and in the morning often thirsts.

12. Gnashing of teeth

Процессы, которые происходят с человеком во время сна

According to research, about 5% of people suffer from a bizarre condition, known as bruxism. This is expressed in excessive grinding of teeth during sleep and ultimately can lead to damage to the teeth. Scientists are not sure what exactly causes this condition, but they believe that it can be a peculiar form of stress relief.

13. The body becomes longer

Процессы, которые происходят с человеком во время сна

It was found that the growth of people can increase by several centimeters in the morning, compared with the evening. During sleep in the horizontal position, the spine is straightened, since the weight of the body does not press on it.

14. Blood pressure drops sharply

Процессы, которые происходят с человеком во время сна

During sleep, any person experiences a condition that is known as a "nightly lowering of blood pressure." On average, it falls at night by 5 - 7 mm. Gt; Art.

15. Sleepwalking

Процессы, которые происходят с человеком во время сна

Scientifically, disorders known as parasomnias (sleepwalking and other activities during sleep) include behavior, emotions, sensations, and dreams that usually occur during transitions between some of the stages of sleep. Parasomnias are mostly harmless, but there have been cases when people were injured during sleepwalking.

16. Sexual arousal

Процессы, которые происходят с человеком во время сна

Both men and women can be aroused during sleep. When the brain is more active during sleep, it requires more oxygen. As a result, the flow of blood throughout the body increases, which leads to swelling of the genital organs.

17. Dreams

Процессы, которые происходят с человеком во время сна

The content and purpose of dreams are not fully understood, but it is known that an ordinary person has from 3 to 5 dreams per night. Dreams mostly occur in the first stage of sleep, when the human brain is the most active. However, most dreams are immediately or quickly forgotten.

18. The brain makes decisions

Процессы, которые происходят с человеком во время сна

A recent study has shown that the brain can process information and prepare for further active activities during sleep, effectively making decisions in the unconscious state. In fact, the brain can even make important discoveries during sleep.

19. Flatulence

Процессы, которые происходят с человеком во время сна

Muscles of the anal sphincter slightly weaken during sleep, which facilitates the outflow of gases from the intestine. The good news is that the sense of smell also weakens during sleep.

20. Purification from toxins

Процессы, которые происходят с человеком во время сна

Getting rid of toxins allows the body and brain to regain strength. In people who do not sleep well, the filtration of harmful substances is not so effective, therefore, experts say: this is what causes people who suffer from insomnia to be slightly insane.

21. Unconscious Awakening

Процессы, которые происходят с человеком во время сна

Scientific research has shown that people wake up many times during sleep, but these awakenings are so short that they do not remember them. As a rule, these spills occur during the transition periods between the stages of sleep.

22. You can stop breathing

Процессы, которые происходят с человеком во время сна

Millions of people around the world suffer from a sleep disorder known as "apnea." The disorder is characterized by pauses between breaths, and each pause can last for a few seconds or even a few minutes.

23. You can hear the explosion

Процессы, которые происходят с человеком во время сна

"Syndrome of an exploding head" is a rare condition in which a person hears loud imaginary sounds (for example, a bomb explosion, the sound of shooting, etc.) or experiences a strange sense of explosion when he falls asleep or wakes up. It is painless, but frightens the sufferer.

24. Talking during sleep

Процессы, которые происходят с человеком во время сна

Conversations during sleep are a parasomnia, in which a person begins to chat uncontrollably aloud during sleep. Such "conversations" can be quite loud and represent both simple muttering sounds, and lengthy, often indistinct speeches.

Physiology of sleep

Процессы, которые происходят с человеком во время сна

In a dream, the level of anabolic processes rises and catabolism decreases. Sleep normally occurs cyclically, approximately every 24 hours. These cycles are called circadian rhythms. They are redefined every 24 hours, the most important factor is the level of lighting. The level of concentration of special photo-dependent proteins depends on the natural cycle of illumination. The circadian cycle is usually set to the length of a light day. Besides night sleep, in some cultures there is a physiologically conditioned short-term daytime dream - siesta.


Immediately before bedtime, there is a state of drowsiness, a decrease in brain activity, characterized by:

  1. Decreased level of consciousness;
  2. Yawning;
  3. A decrease in the sensitivity of sensory systems;
  4. A decrease in heart rate, a decrease in the secretory activity of glands (salivary - dryness of the oral mucosa, tearful - burning eyes, clots of the eyelids).

Professor Richard R. Budzin at the Laboratory of Sleep Research at the University of Arizona for many years studied sleep disorders and recommends a technique for fast falling asleep, based on six stages. In the annual report on clinical psychology, he described the various psychological approaches that were used to treat insomnia (Bootzin & Epstein, 2011). Such treatment was earlier called stimulant control treatment (Morin et al., 2006). Tips include: go to bed, only when you want to sleep, use the bed only for sleeping, do not lie in bed for more than 10 minutes, if you can not fall asleep - make the bed associated only with a fast falling asleep, wake up in the morning on the alarm clock in one and The same time, do not sleep during the day.

Structure of sleep

Sleep - a special state of consciousness of man and animals, which includes a number of stages, regularly repeating during the night (with a normal daily chart). The appearance of these stages is due to the activity of various brain structures.

In a healthy person, sleep begins with the first stage of slow sleep (Non-REM-sleep), which lasts 5-10 minutes. Then comes the 2nd stage, which lasts about 20 minutes. Another 30-45 minutes falls on a period of 3-4 stages. After that, the sleeper returns to the second stage of a slow sleep, after which the first episode of a fast sleep occurs, which has a short duration - about 5 minutes. This whole sequence is called a cycle. The first cycle has a duration of 90-100 minutes. Then the cycles are repeated, while the proportion of slow sleep decreases, and the proportion of fast sleep (REM-sleep) gradually increases, the last episode of which in some cases can reach 1 hour. On average, with a full healthy dream, there are five complete cycles. The sequence of the change of stages and their duration is conveniently represented in the form of a hypnogram that visually reflects the structure of the patient's sleep.

Slow sleep

Slow sleep (syn: slow wave sleep, orthodox sleep), lasts 80-90 minutes. Comes immediately after falling asleep.

  • The first stage. The alpha-rhythm decreases, and low-amplitude slow theta rhythms appear, in amplitude equal to or greater than the alpha-rhythm. Behavior: a nap with sleepy dreams, absurd or hallucinogenic thoughts and sometimes with hypnagogic images (dreamlike hallucinations). Muscular activity decreases, the frequency of respiration and pulse decreases, the metabolism slows down, and the temperature decreases, the eyes can make slow movements. At this stage, ideas that contribute to the successful resolution of a particular problem or the illusion of their existence can appear intuitively. In the EEG, acute vertex waves, POSTS can be recorded, occasionally hypnagogic hypersynchrony is observed. At this stage, hypnagogic twitchings can occur.
  • The second stage. (Shallow or light sleep). Further decrease in tonic muscle activity. The heart rhythm slows down, the body temperature decreases, the eyes are motionless. Occupies a total of about 45-55% of the total sleep time. The first episode of the second stage lasts about 20 minutes. In the EEG dominate theta waves, there are so-called "sleeping spindles" - sigma-rhythm, which is a rapid alpha-rhythm (12-14-20 Hz). With the advent of "sleepy spindles" there is a disconnection of consciousness; In pauses between spindles (and they occur about 2-5 times per minute), a person is easy to wake up. Episodic sleepy spindles can be included in the structure of stages 3-4. The thresholds of perception are raised.
  • The third stage. A slow dream. The stage is classified as the 3rd if the delta-oscillations (2 Hz) occupy less than 50% and the 4th stage - if the delta is more than 50%.
  • The fourth stage. The deepest slow delta sleep. Delta-oscillations predominate (2 Hz). The third and fourth stages are often combined under the name of delta sleep. At this time, it is very difficult to awake a person; 80% of dreams occur, and it is at this stage that attacks of sleepwalking, night terrors, sleep talk and enuresis in children are possible. However, almost none of this person remembers.

In a healthy person, the third stage takes 5-8%, and the fourth stage is still about 10-15% of the total sleep time. The first four slow-wave sleep stages normally occupy 75-80% of the total sleep period. It is suggested that a slow sleep is associated with the restoration of energy costs. Studies have shown that it is the phase of slow sleep that is key to the consolidation of conscious "declarative" memories.

Quick sleep

Rapid sleep (syn: fast wave sleep, paradoxical sleep, fast eye movements, or short for BDG-sleep, REM-sleep). This is the fifth stage of sleep, it was discovered in 1953 by Kleitman and his graduate student Aserinsky. Rapid sleep follows a slow one and lasts 10-15 minutes.

On the EEG, rapid fluctuations in electrical activity are observed, close in value to the beta waves of the sawtooth wave. During this period, the electrical activity of the brain is similar to the state of wakefulness. At the same time (and this is paradoxical) at this stage the person is in complete immobility, due to a sharp drop in muscle tone. However, eyeballs very often and periodically make rapid movements under close eyelids. There is a distinct relationship between the BDG and the dreams. If at this time to wake up the sleeper, then in 90% of cases you can hear a story about a bright dream.

The electroencephalogram reflects the state of activation and resembles the EEG of the first stage of sleep. The first episode of fast sleep comes in 70-90 minutes from the moment of falling asleep, lasts 5-10 minutes. In the course of sleep, the duration of subsequent episodes of BDG sleep increases, reaching in the morning several tens of minutes. In an adult, the proportion of the REM-phase is about 20-25% of the total sleep time. The phase of rapid sleep from cycle to cycle is prolonged, and the depth of sleep decreases. Part of the interrupted fast sleep should be replenished in the following cycles.

It is assumed that a quick sleep provides the functions of psychological protection, the processing of information, its exchange between consciousness and the subconscious.


During a fast sleep, there is an increase in the secretion of adrenal hormones, increased cerebral blood flow, changes in heart rate, various forms of arrhythmia, ups and downs of blood pressure, changes in breathing patterns, penile erection or clitoris.

Functions of sleep

The visceral theory of sleep states that in a dream the central nervous system deals with the analysis and regulation of the work of internal organs.

  • Sleep provides rest to the body.
  • Sleep facilitates the processing and storage of information. Sleep (especially slow) facilitates the consolidation of the studied material, fast sleep realizes subconscious models of expected events.
  • Sleep is the adaptation of the body to changes in illumination (day-night).
  • Sleep restores immunity by activating T-lymphocytes, which fight with cold and viral diseases.

25. Reduced pain threshold

Процессы, которые происходят с человеком во время сна

When the body is completely relaxed to the point of paralysis, nerves can not receive pain signals and transmit them to the brain. This also explains why people do not hear smells, sounds, etc., during sleep.

Necessary duration of sleep

The average duration of a person's sleep usually depends on numerous factors: starting from age, sex, lifestyle, nutrition and fatigue, to external factors (total noise level, location, etc.). In general, with sleep disorders, its duration can range from a few seconds to several days.

There are also cases where an adult needs 12 hours to sleep with a reserve of strength or recover from hard work and sleepless nights. Duration of sleep less than 5 hours (hyposomnia) or a violation of the physiological structure are considered risk factors for insomnia.

Deprivation of sleep is a very difficult test. Within a few days the consciousness of a person loses clarity, he experiences an irresistible desire to fall asleep, periodically "fails" in a border state with confused consciousness. This method of psychological pressure is used during interrogations, and is regarded as a sophisticated torture.


Recent research on the functionality of dreams at the University of Helsinki (led by Prof. Pekka Sutola) showed that the REM sleep phase sometimes occurs quickly in mammals, and then they go into a deep sleep phase. This explains why epileptics have a REM-like phase during an attack and are unable to recall events a few hours before the attack. More complete structure of the functioning of this system has not yet been established.

If the average age is 70 years, then one of them sleeps about 23 years.


Afternoon snooze-holiday - siesta - is a historical element of the culture of many peoples. Most often it occurs in hot countries. A recent study conducted in Greece jointly by the University of Athens Medical School and Harvard, showed that a half-hour afternoon rest-drums at least three times a week reduces the risk of death from a heart attack by 37%.

Pathology of sleep

With persistent disturbances of sleep, there are situations when the intervention of a doctor is necessary. In news reports several cases of long absence of sleep in a person have been published.

  • Dyssomnias are disorders of night sleep, for example, insomnia (insomnia). Causes: neuroses, psychoses, organic brain damage (encephalitis, epilepsy), somatic diseases.
  • Apnea in a dream is a psychogenic or mechanical disturbance of breathing in a dream.
  • Hypersomnia is an insurmountable pathological drowsiness. Examples: narcolepsy, lethargic sleep.
  • Parasomnia is the cause: neurosis. Examples: somnambulism (sleeping / sleepwalking), grinding of teeth, nightmares, epileptic seizures, etc.
  • Sleep paralysis is a condition where muscle paralysis occurs before falling asleep or after awakening.