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, let's look at the phases of fast and slow sleep people 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 arterial pressure and temperature, and other indicators were taken. 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 fast and deep sleep person, and their significance 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 sleep man 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 age of the person and the physical condition of 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 dozing, for the second stage (slowing breathing and heart rate) – 20 minutes, for the third and fourth phases – 30-45 minutes each.
The girl sleeps sweetly, hugging a pillow
Features of REM sleep
Upon completion of the deep comes REM sleep. 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 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. For good rest Long REM sleep is required. 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 active work brain, so awakening occurs softly 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- This 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 The human body needs phase sleep. 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, 11:36Despite the fact that the site already has an article about sleep phases, it seems correct spelling one more article in light of what has appeared new information about sleep cycles and the amount of time it takes a person to get enough sleep.
In order not to duplicate information, I refer everyone to the article Phases of Human Sleep. And in this article we will only do short review the most necessary points regarding sleep phases.
Another thing is sleep cycles. It is the required number of sleep cycles that gives us the opportunity to feel great in the morning after waking up. Moreover, each individual person may differ markedly from others in the number of necessary sleep cycles and, as a result, the time spent on night sleep.
In addition, I think it will be interesting to learn about what capabilities the human body has to compensate for the lack of sleep, both for the previous lack of sleep and for the future.
Let's look at all this in order.
Sleep phases
The sleep phases of any person consist of only two groups:
- Non-REM sleep phase (consists of several types of sleep);
- REM sleep phase.
These two sleep phases constantly alternate throughout a person’s entire sleep time, forming a single completed sleep cycle. That is, the sleep cycle consists of 1 phase of slow sleep and 1 phase of REM sleep. The duration of the sleep cycle usually ranges from 1 to 1.5 hours. Then comes new cycle similar duration.
Non-REM sleep stages initially occupy up to three-quarters of the total duration of the sleep cycle. But with each new cycle, the duration of the sleep phase within a given cycle changes towards reducing the duration of slow-wave sleep and increasing the rapid phase.
According to available data, somewhere after 4 o'clock in the morning, the phase of slow sleep (deep type) completely disappears, leaving only REM sleep.
What happens during non-REM and REM sleep?
The human body needs slow-wave sleep for recovery physical functions. At this time, the process of renewal of cells and internal structures occurs, energy is restored, muscles grow, and hormones are released.
During the fast phase of sleep, work occurs at the level of the mental and emotional spheres: restoration nervous system, information is processed, memory and other structures of the body are prepared.
It turns out that each phase of sleep is extremely important for the next day of the body’s functioning.
Sleep cycles
But during one phase of sleep, the body does not have time to make all the necessary changes. Therefore, in order to fully restore and prepare the body for further activities Several repeating cycles are needed throughout the day.
Today, scientists say that the average person needs 5 repeating sleep cycles. This adds up to about 7-8 hours of sleep a night.
However, there are a fair number of people who have deviations in the number of cycles in one direction or another.
There are people who are able to fully recover in just 4 sleep cycles. They often only need 4-6 hours of sleep during the night to feel great the whole next day.
On the other hand, many people feel constantly groggy if they sleep less than 9 hours a night. Compared to other people who sleep fewer hours, such people look lazy. However, if you understand that they just need not 5, but 6 sleep cycles at night, then everything falls into place. 6 sleep cycles of 1.5 hours each give you 9 hours of sleep at night.
How much sleep do you need to get enough sleep?
To get enough sleep, each individual person needs to sleep exactly as many sleep cycles as his body requires. Usually this is 4-6 sleep cycles.
At the same time, the duration of sleep will also fluctuate considerably, because... Each person has their own sleep cycle length.
Scientists recognize 4 sleep cycles as the minimum that allows the body to more or less restore its strength. But at the same time, it is necessary to ensure that all these 4 sleep cycles are completed before 4 o’clock in the morning. This will completely complete all the body’s work to restore physical structures.
In any case, every person knows approximately how many hours of sleep he needs to feeling normal. Based on this, we can conclude about the required number of sleep cycles.
Deep sleep is a complete night's rest. A person’s performance, emotional and physical state. The norm for deep sleep for an adult is from ninety to one hundred and twenty minutes, taking into account several nightly cycles. The duration of healthy sleep for a person is eight to nine hours a day. It consists of four full periods: nap, shallow, slow and deep sleep. Napping is characterized as a superficial state lasting five minutes. At this stage, the body temperature becomes lower, the pulse and metabolism slow down, and breathing becomes quiet. When falling asleep, consciousness turns off, but the reaction to external stimuli remains.
Deep sleep mode helps the body cope with stress and ailments. It helps strengthen immune system. Immersion in deep sleep lasts for an hour, after which the rapid phase begins.
Full night cycle healthy person consists of a slow and a fast phase, and takes only about one hundred and twenty minutes. Approximately four cycles occur during the night, the duration of which depends on individual characteristics. The first cycle begins with deep sleep. It lasts a long time, but gradually its duration decreases.
How long should deep sleep last for an adult? Normal cycle is considered to be one that consists of a slow and fast phase, taking into account individual biorhythms. The slow phase consists of the states of drowsiness, falling asleep, deep and delta sleep. During the longest cycle, the human body completely relaxes, functions fade, and weak impulses pass through the brain. It is during this period that the body restores strength and recharges itself with energy.
What are the stages of the slow phase? What makes them special?
- Nap. A person begins to fall asleep, but the brain continues to be active and creates dreams intertwined with reality. The peculiarity is that it is in the state of drowsiness that the answers to seemingly insoluble problems are found.
- Falling asleep. The slow phase continues. Consciousness gradually turns off, but the brain continues to respond. At this stage, a person can easily be awakened by even a small noise.
- Deep. Changes begin in the body, all processes and functions slow down, and the body completely relaxes.
- Delta. It is difficult to wake up a person, since the body is completely relaxed, its temperature drops, and the breathing rate and blood circulation slow down.
How long does slow-wave sleep last? This stage is the longest and depends on the characteristics of the body. Physical endurance and mental activity depend on its quality. If a person does not get enough sleep, he will feel exhausted. Insomnia completely exhausts the body, leading to illness. How many hours does an adult sleep in total? You need to sleep at least eight hours a day. The duration of sleep depends on many factors: age, health, working conditions, biorhythms.
How to increase your night's rest? This is an integral part of human life. In a healthy person it lasts eight hours, but it all depends on biorhythms. For example, older people need less time to sleep, and a growing body needs twice as much time as an adult. Some people need nine hours for proper rest, while others need six. Everything is individual. The main thing is to feel cheerful during the day and be in in a great mood.
NREM sleep consists of four phases: nap, sleep, deep and delta. The peculiarity is that it is very difficult to wake up a sleeping person in the last two cycles.
It is at this time that dreams occur, including nightmares. Normal condition- this is when the four stages of one cycle occupy eighty percent of all sleep.
Deep and slow sleep have their own characteristics:
- in the slow phase, the body physically recovers, strength is restored, tissues and cells are regenerated;
- people who sleep seven to eight hours a day recover intellectual resources faster, and their daytime activities are much more effective;
- An increase in sleep duration helps strengthen the immune system, and a decrease in sleep helps reduce protective functions body;
- if the slow phase lasts a small number of hours, the aging of the body noticeably accelerates;
- if the deep phase did not last long, signs such as memory deterioration, inability to concentrate on the subject of conversation or problem, and decreased performance appear;
- the slow phase, unlike the fast one, does not have compensatory properties; it is impossible to “get enough sleep” the next night.
Thus, human health depends on the number of hours of the slow phase. If you want to improve your night's rest, you just need to train your body to fall asleep at approximately the same time. The deep phase occupies 12 to 15% of the cycle and is characterized by rhythmic, calm breathing and complete relaxation of the body. The cycle ends with the dreaming stage, during which the pulse and breathing increase.
How long does it take to get a good night's sleep? In this matter, everything is individual. To someone for normal healthy rest It only takes five hours; others need ten to get enough sleep. On average, for most people, the overnight recovery period lasts between seven and eight hours. What is REM sleep? This period ranges from ten to twenty percent, the remaining eighty is occupied by the slow phase.
The more hours a person sleeps during the delta phase, the better he will feel during the day. A properly structured rest regime and its observance increases the duration of the deep cycle. In order to double your deep sleep time, somnologists recommend following some tips.
- The normal state of the body is guaranteed by a well-structured regime of falling asleep and waking up. If you independently adjust the duration of rest at night, waking up in the morning will be much easier.
- Somnologists do not recommend eating heavy food before going to bed. Smoking, energetic drinks, caffeine - all this negatively affects sleep. A good snack would be a glass of kefir or milk, as well as an apple or any other fruit.
- The deep phase will last longer if you give the body adequate physical activity about four hours before rest.
- Walking on fresh air, active lifestyle, intense physical exercise during the day they contribute falling asleep quickly and strong good sleep. Light music and aromatherapy will improve your relaxation. Experts say that the quality of deep sleep is positively influenced by the singing of crickets.
- Before going to bed, it is important to ventilate the room well. Foreign odors, bright light, as well as noise do not contribute to falling asleep and the duration of rest.
If you follow these recommendations, you can forget what insomnia is and significantly increase the length of the slow phase. Its peculiarity is that it is during this period that a person restores his physical abilities. Fast phase helps to improve the functioning of mental processes. Healthy, well-functioning sleep improves immunity, normalizes blood pressure, reduces the risk of heart and vascular diseases, and also mental disorders.
Characteristics of deep sleep
During the night's rest, slow-wave and fast-wave periods alternate with each other. The cycle consists of one period of slow and fast sleep. In total, four to six cycles change each night, lasting an hour and a half. For a child and an adult, the norm is that the deep period is thirty percent.
If a sleeper is abruptly awakened during the deep sleep phase, he will feel tired and exhausted during the day. In people with arterial hypertension pressure surges may occur.
The peculiarity is that if a person sleeps well, he will wake up on his own in the morning even from a little noise, and getting up in the morning will be easy. During deep sleep, contact with reality is lost, the body completely relaxes, which gives it the opportunity to recover.
During such a rest, some changes occur in the body:
- muscles completely relax, metabolism slows down;
- most active at night parasympathetic division CNS, so the pulse becomes slower, blood pressure drops, the brain practically does not react to external stimuli;
- the gastrointestinal tract slows down its activity, so sometimes upon waking up you may feel slight nausea;
- the cells of the body are restored at night, as growth hormone is actively produced;
- the body spends a lot less energy than during the day;
- immunity is strengthened;
- If you sleep longer than usual, your physical capabilities increase.
REM sleep is the exact opposite of deep sleep. The body consumes a large number of oxygen, glucose, breathing quickens, pulse increases. Women and men sometimes feel aroused and an erection occurs. Doctors advise sleeping at least seven hours a day. For children, pregnant women and sick people various diseases this norm is higher.
How dangerous is lack of adequate sleep? Almost every person has experienced insomnia at least once. When you try to sleep but can’t, it causes irritation and the body loses more strength than during the day. Isolated cases of insomnia do not harm health; if it becomes systematic, problems arise. In this case, sleepy medications are prescribed natural tablets or sleeping pills, depending on the duration of insomnia.
Sleep disorders are a broad concept that includes problems falling asleep, changes in the process of resting at night, and bad feeling after waking up. All of them are temporary, reversible disorders, but they manifest themselves in the same way. A person feels fatigue, lethargy, apathy, decreased mood, and lacks motivation to work.
The main causes of the disorder are problems of a psycho-emotional nature and somatic diseases.
- Long-term insomnia is provoked by chronic stress, overexertion, and traumatic factors. Sometimes it becomes cause and effect depressive state, as well as other mental disorders.
- Diseases of the heart, blood vessels, central nervous system, malignant neoplasms play an important role in deep sleep disorders. Painful sensations, intrusive thoughts illnesses, injuries, osteochondrosis, frequent urge to urinate become grounds for insomnia.
- Heavy physical exercise, unfinished business and questions.
- Poisoning, problems with gastrointestinal tract.
- Heat bodies.
If sleep is disturbed, there must be some changes in emotional sphere person. It has been proven that people with psychological problems, high level anxiety and depression.
Treatment for insomnia is prescribed after the cause of the condition has been found. To prevent such disorders, it is recommended to walk in the fresh air more often and include vegetables and fruits in the diet. Folk remedies, aromatherapy - all this helps in the fight against the disease.
Is physiological process, in which a person (as well as mammals, fish, birds and some insects) is in a state radically different from the waking state. This condition characterized by altered consciousness, decreased level brain activity and reactions to external stimuli. Natural sleep differs significantly from such similar states as coma, suspended animation, fainting, sleep under the influence of hypnosis and Sopor. Along with sleep in the usual sense of the word (i.e. sleep at night), certain cultures allow the existence of the so-called daytime rest or siesta. Short-term nap is part of the traditions of many peoples. According to the results of ongoing research, regular afternoon naps can significantly reduce (by almost 40%) the risk of a heart attack. In a word, sleep is the most important element human life and at the suggestion of researchers, since 2008, every 3rd Friday of the first month of spring is celebrated as Sleep Day.
Basic functions of sleep
Thanks to sleep, the body receives the necessary rest. During sleep, the brain processes the information accumulated during the day. The so-called slow sleep allows you to better assimilate the studied material and consolidate it in memory. REM sleep provides the ability to simulate upcoming events at the subconscious level. Important function sleep is also the restoration of the human immune system by activating the activity of T-lymphocytes that resist viral infections and fight colds.
Physiology of the sleep process
Healthy sleep can last from 4 to 8 hours. However, these indicators are quite subjective, since the duration of sleep depends on physical fatigue person. A significant amount of work done during the day may require a longer night's rest. Normal sleep is cyclical and required to the human body at least once a day. Sleep cycles are called circadian rhythms. Every 24 hours, circadian rhythms are redefined. The most important factor during sleep, illumination is considered. The concentration of photodependent proteins in the body depends on its natural cycle. Usually, circadian cycle correlates with the length of daylight hours. Just before sleep sets in, a person feels drowsy and brain activity decreases, and a change in consciousness is also noted. In addition, a person who is in a sleepy state experiences a decrease in sensory sensitivity, a decrease in heart rate, yawning, and in addition a decrease in the secretory function of lacrimal and salivary glands. One more physiological feature sleep is a process called “vegetative storm”, i.e. when various forms of arrhythmias are observed, an increase or decrease in blood pressure, increased blood supply to the brain and secretion of the adrenal glands, erection of the clitoris and penis.
Structure of the sleep process
Any sleep is divided into several stages, which are repeated with a certain pattern throughout the night (naturally, provided that the daily schedule is absolutely normal). Each stage of sleep directly depends on the activity of one or another brain structure. The first stage of sleep is slow-wave sleep (Non-REM). The duration of Non-REM sleep is 5 to 10 minutes. This is followed by the second stage, lasting approximately 20 minutes. Over the next 30-45 minutes, another 3 and 4 stages of sleep are observed. Next, the person again falls into the second stage of slow-wave sleep, at the end of which rapid REM sleep occurs (episode 1). This is approximately 5 minutes. All of the above stages are the first sleep cycle, which lasts from 90 to 100 minutes. After this, the cycle repeats again, but at the same time the stages of slow-wave sleep are reduced, and REM sleep, on the contrary, increases. Typically, the last sleep cycle ends with an episode of REM sleep, lasting in some cases about 1 hour. Full sleep includes 5 full cycles. The sequence in which one stage of the sleep cycle follows another, as well as the duration of each cycle, is usually presented in the form of a hypnogram. The sleep cycle is regulated by certain areas of the cerebral cortex, as well as the locus coeruleus, located in its trunk.
What is slow wave sleep?
NREM sleep (also called orthodox sleep) lasts 80 to 90 minutes and occurs immediately after a person falls asleep. The formation and development of slow sleep is ensured by the anterior parts of the hypothalamus, raphe nuclei, nonspecific nuclei of the thalamus and middle part bridge (the so-called Moruzzi brake center). At the first stage of slow-wave sleep, the alpha rhythm decreases, transforming into slow low-amplitude theta rhythms, equal in amplitude to the alpha rhythm or exceeding it. The person is in a state of drowsiness (half-asleep), and dream-like hallucinations are observed. Muscle activity decreases, heart rate and breathing decrease, metabolic processes slow down, eyeballs make a slow motion. At this stage of sleep, solutions to problems that seem unsolvable during wakefulness are intuitively formed. By at least, the illusion of their existence may arise. The first stage of slow-wave sleep may also include hypnogogic jerks.
In the second stage of Non-REM sleep (this is usually light and shallow sleep), a further reduction in muscle activity occurs, the heart rate slows down, body temperature drops, and the eyes become motionless. The second stage is approximately up to 55% of the total sleep time. The first episode of the second stage lasts approximately 20 minutes. The electroencephalogram shows at this moment the predominant theta rhythms and the emerging sigma rhythms (the so-called “sleep spindles”), which are essentially rapid alpha rhythms. At the moment of the appearance of sigma rhythms, consciousness turns off. However, during pauses between sigma rhythms, which occur at a frequency of 2 to 5 times per minute, a person can be easily awakened.
At the third stage of slow-wave sleep, the total number of delta rhythms is no more than 50%. At the fourth stage this figure exceeds 50%. The fourth stage is slow and deep sleep. Quite often stages III and IV are combined and called delta sleep. It is extremely difficult to wake a person during delta sleep. Dreams usually appear at this stage (up to 80%). A person may begin to talk, sleepwalking is possible, nightmares may occur and enuresis may develop. At the same time, a person usually does not remember any of the above. The third stage lasts from 5 to 8% of the total sleep time, and the fourth stage takes from 10 to 15% of the entire sleep period. The first four stages of slow-wave sleep normal person last from 75 to 80% of the total duration of this physiological process. According to researchers, Non-REM sleep provides full recovery energy expended per day. In addition, the slow-wave sleep phase allows you to record conscious memories of a declarative nature in your memory.
What is REM sleep?
Rapid eye movement sleep is also called REM sleep. paradoxical dream or fast wave sleep. In addition, the generally accepted name is the REM (rapid eye movement) stage. The REM stage lasts 10 to 15 minutes and follows non-REM sleep. REM sleep was discovered in 1953. The centers responsible for REM sleep are: the superior colliculus and the reticular formation of the midbrain, the locus coeruleus, as well as the nuclei (vestibular) medulla oblongata. If you look at the electroencephalogram at this moment, you can see quite active fluctuations in electrical activity, the values of which are as close as possible to beta waves. During REM sleep, the electrical activity of the brain is almost identical to the waking state. However, at this stage the person is completely motionless, since his muscle tone is zero. At the same time, the eyeballs actively move under closed eyelids, moving quickly with a certain periodicity. If you wake up a person in the REM stage, there is a 90% chance that he will report an exciting and vivid dream.
As noted above, the electroencephalogram of REM sleep reflects the activation of brain activity and is more reminiscent of the EEG of the first stage of sleep. The first episode of the REM stage lasts from 5 to 10 minutes and occurs 70-90 minutes after the person falls asleep. Throughout the entire sleep period, the duration of subsequent episodes of REM sleep becomes increasingly longer. The final episode of REM sleep can last up to 1 hour. The duration of REM sleep in a healthy adult is approximately 20-25% of the total sleep time. From one cycle to the next, the REM sleep phase becomes longer and longer, and the depth of sleep, on the contrary, decreases. Disturbances of slow-wave sleep are not as severe for the psyche as interruption of the REM phase. If any part of REM sleep is interrupted, it must be replenished in one of the subsequent cycles. Experiments conducted on mice have proven the detrimental effect of the missing REM phase on these mammals. After 40 days, the mouse deprived of REM sleep died, while the rodents deprived of slow-wave sleep continued to live.
There is a hypothesis that during the REM phase, the human brain works to organize the information received during the day. Another theory is that REM sleep is especially important for newborns, providing neural stimulation that promotes the formation and development of the nervous system.
Sleep duration
Duration normal sleep can vary from 6 to 8 hours per day. However, this does not exclude large deviations in one direction or another (4-10 hours). If sleep disturbances are observed, then its duration can be equal to several minutes or several days. When the duration of sleep is less than 5 hours, this is considered a violation of its structure, which can lead to the development of insomnia. If you deprive a person of sleep, then within a few days his consciousness will lose clarity of perception, an irresistible urge to sleep will appear, and “dips” into the so-called borderline state between sleep and wakefulness will be observed.
Dreams
Along with the corresponding physiological process, the word “sleep” also means a sequence of images that arise in the REM sleep phase and, in some cases, are remembered by a person. A dream is formed in the consciousness of a sleeping person, consisting of a variety of subjectively perceived tactile, visual, auditory and other images. Usually the person who is dreaming is not aware that he is in a dream state. As a result, the dream is perceived by him as an objective reality. An interesting type of dreams are considered lucid dreams, in which a person understands that he is dreaming, and therefore can control the development of the plot in a dream. It is believed that dreams are inherent in the REM sleep phase, which occurs once every 90-120 minutes. This phase is characterized by rapid movement of the eyeballs, increased heart rate and breathing, stimulation of the pons, as well as short-term relaxation of skeletal muscles. According to the results of recent research, dreams may also be characteristic of the slow-wave sleep phase. At the same time, they are less emotional and do not last as long as REM dreams.
Sleep pathologies
All kinds of sleep disorders are quite common. For example, the cause of insomnia (insomnia) can be psychosis, depression, neurosis, epilepsy, encephalitis and other diseases. Apnea is a breathing disorder of a sleeping person, the causes of which can be mechanical or psychogenic in nature. Parasomnias such as sleepwalking, nightmares, epilepsy and teeth grinding are formed and develop on the basis of neurosis. Pathologies such as lethargic sleep, narcolepsy and sleep paralysis are among the most severe disorders sleep. In case of any alarming factors associated with obvious deviations in the structure of sleep, you should seek help from a specialist.
Pharmacological hypnotics
Sleep regulation using pharmacological agents must be carried out under the supervision of a physician. Along with this, it should be remembered that long-term use sleeping pills reduces the effectiveness of the latter. Relatively recently, the group of sedatives even included drugs - morphine and opium. Barbiturates have also been used as sleeping pills for quite a long time. One of the most progressive this moment melatonin is considered a drug. No less effective treatment Insomnia is helped by taking magnesium supplements, which improve sleep and promote the production of melatonin.
Sleep Study
According to prominent researchers of the past and present, sleep plays a more important role for the human body than food. In the second half of the 20th century, technologies for recording the activity of muscles (EMG), brain (EEG) and eyes (EOG) were developed, after which it was possible to formulate ideas about the structure of sleep and its nature, which no one has yet refuted .
Healthy sleep is one of the basic needs of humans, and indeed of all higher living organisms.. Even plants hibernate during the day, which is confirmed by research into their functions, which slow down during this period. There are regularly reports in the press about people who do not sleep at all. But most often this is a serious pathology that brings great suffering to a person. It is not for nothing that there used to be a special torture - sleep deprivation, due to which the person subjected to it would eventually either completely break down or even die. All information about people who do not sleep and feel great turns out to be false.
We need healthy sleep for many reasons.. Firstly, thanks to him, our body rests. Brain activity and cardiac activity slow down, muscles relax.
Of course, even during the deepest sleep, organs and systems continue to work, but the load on them is significantly less than during wakefulness. Restoration occurs in sleep damaged cells, and almost all the energy that is directed during the day to maintaining various functions the body goes for these purposes.
Secondly, sleep is vital for our immunity. It is during night rest that T-lymphocytes, the cells responsible for fighting bacteria and viruses, are activated.
It’s not for nothing that they say that a dream is best medicine. Bed rest and sleep help cope with illnesses no worse than pills.
Third, thanks to sleep, our brain gets the opportunity, without being distracted by other things, to process all the information received by it during the day. What is not needed is “erased”, and information and impressions that may be useful are put aside. long-term memory. People suffering from insomnia almost always have memory problems.
Fourth, sleep regulates the level of hormones, including those responsible for our adaptation to changing times of day and seasons. We sleep at night because our senses are not adapted to activity in the dark. During the off-season, when the weather and daylight hours change, sleep helps us better adapt to these changes.
Sleep duration needs may vary depending on different people, but on average you need to get at least 7-8 hours of sleep every day. Usually, a person sleeps a third of his entire life. During this time, we have time to rest, restore strength, and sometimes even recover.
NREM sleep phase
During this period, the body heals, its cells are restored and energy reserve. In the slow-wave sleep phase, the breathing rate decreases, the heart rate decreases, and the muscles relax. NREM sleep, in turn, is divided into four stages.
The first is drowsiness, when a person, half asleep, experiences the events of the past day. On next stage consciousness turns off, but periodically, approximately 2-5 times per minute, a state of high auditory sensitivity occurs. At these moments, we easily wake up even from slight noise. In the third and fourth stages of slow-wave sleep, a person completely switches off and fully rests, his strength is restored.
REM sleep phase
During this period, the activity of the respiratory and cardiovascular systems. At the same time, under closed eyelids, the eyeballs actively move. It is in this phase that a person dreams.
If you wake up at this time, you will clearly remember their contents. During the REM sleep phase, the information received by the brain during the day is processed. It is believed that waking up during this phase is not very healthy, and if this happens, the person feels tired and exhausted.
In total, during the period of night sleep there are 4-5 complete cycles. Moreover, the duration of slow and fast sleep changes in each cycle: slow sleep becomes shorter, and fast sleep becomes longer.
For some people, 6 hours is enough to get a good rest (this is the minimum amount of time you need to sleep at night). For others, 9-10 hours is not enough. So how much sleep do you need?
Physiologists believe that the main thing is that sleep should be a multiple of a full cycle, consisting of slow and fast sleep. And these data are confirmed by numerous studies.
In practice it will look like this. The duration of deep sleep is 80-90 minutes, fast sleep is 10-15 minutes. That is, a full cycle takes approximately 1.5 hours. To get a good night's sleep, you need 4-5 of these full hour and a half cycles. It all depends on how tired you are during the day.
Let's say you go to bed at 11 pm. Then you need to wake up either at 5 am or 7:30 am. In this case, you will not feel overwhelmed, since awakening will occur during the alternation of the phases of fast and slow sleep.
Of course, this is just an ideal scheme. It should be taken into account that on average it will take 10-15 minutes to fall asleep. In addition, depending on your condition, the phases of slow and fast sleep may differ in duration.
If you want to always wake up in right time, you can try purchasing a special alarm clock. It includes a bracelet that monitors your heart rate and tells your alarm to sound when you're in the transition from REM to NREM sleep—the most best time for waking up.
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