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

Many people have heard that sleep consists of sequentially replacing each other. phases and stages. Some people know that in some phases it is easier to wake up, in others it is harder, so ideally, awakening should be adjusted to certain stages of sleep. Someone will say that dreams occur only in one phase (small spoiler - in fact this is not so, see below). In this article, we propose to delve deeper into these and other issues related to different periods of sleep, and consider, what phases stand out, what is their characteristic And duration, how many phases are needed in order to get enough sleep, and how to independently calculate sleep phases. In addition, in the last part of the text we will look at how some so-called rational sleep patterns are assessed in terms of phases and stages.

Phases of human sleep: preface

Dreams seem like such an ordinary thing, and yet it is one of those areas that still holds many mysteries. In particular, so far there is no consensus among scientists even regarding whether we see But stages and phases of human sleep can be considered fully studied, including because they are easier to study using various instruments. The main sources are colored dreams or black and white. data for scientists - the activity of the brain in general and its lobes in particular (shown on the electroencephalogram - EEG), movements of the eyeballs and muscles of the back of the head. These and a number of other indicators make it possible to draw a more or less clear picture of sleep phase cycles.

In general, we propose not to delve into the terms and methods of somnology (the science of sleep), but to consider the phases of sleep on a more practical level: understand how many phases are distinguished, analyze their main features and what distinguishes the phases from each other. This knowledge will help answer questions about which phase is easier to wake up in, how long a healthy sleep should last, etc. But first let's do a few remarks:

• phases and stages are discussed with examples adults(with age, the ratio and duration of the phases changes);
• For simplicity and consistency, sleep periods will be shown using examples from those who goes to bed in the evening or at the beginning of the night, and not in the morning and does not work at night;
• we only consider physiological sleep– medicinal, hypnotic, etc. are not taken into account in this material;
• we will focus on those who are lucky enough to sleep a sufficient number of hours for your body and is not forced, for example, to run to the first class after writing a coursework all night.

So, what should normal sleep be like for the average healthy person under such conditions?

In general, experts divide sleep into two phases:

• slow sleep, aka orthodox, or NREM sleep. The name NREM comes from the English Not Rapid Eye Movement and reflects the fact that this phase is not characterized by rapid eye movements.
• REM sleep, aka paradoxical, or REM sleep(i.e. rapid eye movements are present). The name “paradoxical” comes from the fact that during this phase of sleep, complete muscle relaxation and high brain activity are combined. It turns out that during this period the brain works almost the same as when awake, but it does not process information received from the senses and does not give orders to the body how to react to this information.

The NREM + REM sleep cycle lasts approximately 1.5-2 hours(more details below), and during the night these phases successively replace each other. Average 3/4 cycle falls on slow-wave sleep and, accordingly, about a quarter– to fast.

At the same time, slow-wave sleep has a number of stages:

1. nap– transition from wakefulness to sleep;
2. light sleep;
3. moderately deep sleep;
4. deep dream- It is at this stage that sleep is the deepest.

Stages 3 and 4 are collectively called - delta sleep, which is associated with the presence of specific delta waves on the EEG.

Diagram of the night cycle by phases and stages of sleep

In terms of sleep cycles, our night goes like this:

• First comes stage 1 slow-wave sleep, that is, we move from wakefulness to sleep through drowsiness.
• Next we sequentially go through stages 2, 3 and 4. Then we move in the reverse order - from delta sleep to light sleep (4 - 3 - 2).
• After stage 2 comes phase REM sleep. Due to the fact that it is the last to be activated in the cycle - after all other stages have passed - it is sometimes called phase 5 or stage 5, which, strictly speaking, is not entirely accurate, because REM sleep is completely different compared to slow wave sleep .
• Then we go back to stage 2, and then we again plunge into delta sleep, then light, then fast, then light again... And so the change of phases and stages goes in a circle. Another option is that after REM sleep, awakening occurs.

Duration of sleep phases and stages

As we said above, the entire sleep cycle (slow and fast sleep) takes on average about 1.5 hours to 2 hours. At the same time, the duration of phases and stages and their ratio within one cycle changes over the course of the night. Let's look at how the phases are distributed on average and how long each of them lasts.

Thus, in the first cycle, full-fledged deep sleep (stage 4) occurs approximately 40-50 minutes after sleep, and fast – In 1.5 hours. Based on the average need for sleep, we find that in a normal state a person needs to sleep 3-6 cycles per night - depending on their duration and his need for sleep. In turn, this need varies greatly: some need 4 hours, for some the norm may exceed 10 hours.

In what phase is it better to wake up and how to calculate it

As is known, It's easiest to wake up during REM sleep, in second place is the lung stage. Knowing the sequence of different periods, you can guess the optimal time to wake up. On the other hand, we must take into account that the duration of the phases varies from person to person; in addition, the need for one or another “type” of sleep varies depending on the state. For example, if you are tired, sick, or recovering from an illness, slow-wave sleep may take longer.

Of course, to make it easier for you to wake up, you can buy various gadgets that read the characteristic features of the phases (more details below) and wake you up.
you exactly at the right time. But you can find out how to wake up during REM sleep on your own - First of all, you need to experiment. For example, take 2 hours as a sleep phase, calculate what time you need to go to bed/wake up in order to withstand a whole number of cycles. For example, if you have to get up at 8 am, the multiples of the phases would be 6 am, 4 am, 2 am, midnight, etc. When calculating the time, take into account the fact that you will need a little more time to fall asleep. As we said, Stage 1 usually takes 5-15 minutes. That is, to get up at 8, you need to go to bed at 1:45 or 23:45.

Try to stick to this schedule for a while and see if you can wake up in REM sleep. If not, "play" with the boundaries - make the calculation based on 1 hour 50 minutes or 1 hour 40 minutes. Thus, you can find exactly your duration of the night cycle and build on it in the future. It is best to conduct experiments when you are in a normal physical and emotional state and had more or less normal sleep on the eve of the experiments.

We also hint that by “go to bed” we mean exactly go to bed, and not “go to bed with a smartphone in an embrace and chat in instant messengers for another hour.” We also note that the calculation of sleep phases will not give you vigor if you have been sleeping only one cycle per night for a week. Adjusting to the phases is a tool for waking up easier, but it will not free you from the need to fully sleep.

Phases of sleep and dreams

What happens to us in different stages of sleep

One of the main differences between the phases is different brain activity, which can be visually traced in the waves on the EEG, but the physiology of the sleep phases is characterized not only by this. Another distinction between fast and slow is reflected in the English names REM and NREM - the presence and absence of rapid eye movements. In general, determining the sleep phase by eye, without taking into account instruments and measuring various indicators, is quite problematic. We can only say that if a person moves his eyes, limbs, etc., most likely we are talking about REM sleep. What can be registered on various devices? Here are some interesting facts.

Traits of slow-wave sleep

To plunge into the first stage of slow-wave sleep (drowsiness), the brain produces special substances that block its activity, cause lethargy, and also affect other body systems, including slow down metabolism. In stages 2-4, especially during delta sleep, metabolism also slows down.

To say that during slow-wave sleep, in principle, no eye movements, not entirely true - they are in stages 1 (drowsiness) and
2 (light sleep), but specifically slow; in English terminology they are called slow rolling eye movement (SREM). In turn, during delta sleep there are not even such movements, but it is in this phase that people walk or talk in their sleep, and also perform other uncontrolled actions, if this is typical for them.

Traits of REM sleep

One of the main features of REM sleep is the most vivid dreams. By the words “the most vivid” we mean that almost all the dreams that we remember after waking up are from this phase. It is believed that REM sleep, in turn, is responsible for processing information received during the day, internal work on emotions, etc. But so far scientists cannot say exactly how exactly what happens during REM sleep and what mechanisms are involved.

As we have already noted, visual REM sleep can be recognized by the movements of the eyeballs, sometimes ragged breathing, hand movements, etc. This phase is also characterized by changes in body temperature and heart rate: they can increase or decrease within the same stage.

I wonder what brain activity during REM sleep is so high that scientists for a long time could not notice the difference on the EEG between this phase of sleep and wakefulness. True, to date several important differences have been found.

Interesting features associated with sleep phases

It is typical for any phase distorted view of time. Probably everyone is familiar with situations when you close your eyes for a minute and 5 hours are gone. The opposite is also true: it seemed like the whole night had passed and I had a lot of dreams, but in fact only 20 minutes had passed.

Some people believe that during sleep a person is completely disconnects from reality, however, in reality this is not the case. Many signals are indeed not processed properly by the brain, especially during
delta sleep, but during REM sleep, sounds become the main source of information. For example, we are not always awakened by noise, but a person can wake up from the fact that someone even quietly calls his name. Also, during REM sleep, sounds can be integrated into the dream and become part of it. This suggests that the brain processes sounds during sleep and decides what to pay attention to and how exactly to do it.

In children, the proportion of REM sleep is greater than in adults, and in older people it is even less. That is the older we get, the shorter the paradoxical phase sleep and longer orthodox. Interestingly, REM sleep is observed even in children in the womb. Scientists say that in the early stages of life (including before birth), REM sleep is very important for the formation of the central nervous system.

Research shows that the brain may not be immersed entirely in the same phase, which is especially characteristic of delta sleep. Although most of the brain is usually at the same stage.

The importance of sleep phases for the body: a small warning

It is impossible to say which sleep is better or more useful - fast or slow. Both phases are needed for proper rest and recovery. the body both at the physiological and mental levels. In this regard, questions arise about sleep patterns in which there is no full cycle. Surely many have heard about schemes that suggest that a person sleeps not once a day for 6-8 hours, but several times during the day.
Some of these schemes seem quite harmless, but the benefits of others are seriously questionable.

In particular, there is information on the Internet about a supposedly very effective schedule when you need to sleep 6 times for 20 minutes or 4 times for 30 minutes. Based on a typical sleep cycle, these time periods are very short, and in 20-30 minutes a person will not have time to move beyond stages 2-3, that is, we are not talking about deep and REM sleep in principle. Meanwhile, the most important processes for our body occur precisely at these stages. It is possible that people who are described as having success with such regimens have very compressed sleep cycles, but there is a good chance that the reality is simply embellished for the sake of an impressive story.

Of course, for some time the average person’s body will function on 20 minutes 6 times a day. It may even seem to him that he has become more efficient in using his time, but the benefits of these schemes for the body in this case raise questions. A systemic lack of sleep affects both mental and physical health and leads to various unpleasant consequences. Without denying the benefits and effectiveness of other rational sleep patterns, we urge you to consult your doctor and be very wary of options that do not include at least several full cycles per day.

During sleep, a person periodically alternates two main phases: slow and fast sleep, and at the beginning of sleep the duration of the slow phase predominates, and before awakening, the duration of fast sleep increases. Sleep begins with the first stage of slow-wave sleep (Non-REM sleep), which lasts 5-10 minutes. Then comes the 2nd stage, which lasts about 20 minutes. Another 30-45 minutes occur during stages 3-4. After this, the sleeper returns to the 2nd stage of slow-wave sleep, after which the first episode of REM sleep occurs, which has a short duration of about 5 minutes. This entire sequence is called a cycle. The first cycle lasts 90-100 minutes. Then the cycles are repeated, with the proportion of slow-wave sleep decreasing and the proportion of fast sleep (REM sleep) gradually increasing, the last episode of which in some cases can reach 1 hour. On average, with full healthy sleep, there are five full cycles.

First: Restore the conditions that automatically trigger sleep in the cocaine addict.

• For this we need: to obtain adequate physiological conditions.
• Get an adequate sleeping environment.
• Achieve physical and cognitive deactivation.

To develop a good detoxification treatment, we must achieve the physiological conditions necessary for sleep and adapt the behavior of the cocaine addicted patient in such a way as to change their personal habits.

That's why our detox team usually prescribes. Alcohol metabolism uses a lot of water, so you need to avoid excess alcohol to avoid waking up thirsty in the middle of sleep. Monitor the indoor environment by ensuring that the room temperature is cool and pleasant, that there is no strong light, and that humidity is adequate. Make sure the bed is large enough that the mattress and mattress are firm and comfortable enough so that clothing is not skimpy, excessive or irritating. Noise is an important sleep disruptor, so we must ensure that our sleep time is quiet and noise-free. Jacobson's Deep Muscle Relaxation: The Jacobson's relaxation method is used in our cocaine detoxification clinics to promote sleep as it teaches us to reduce muscle tension and therefore promotes physiological detoxification.

slow sleep

NREM sleep also has its stages.

First stage. The alpha rhythm decreases and low-amplitude slow theta and delta waves appear. Behavior: drowsiness with half-asleep dreams and dream-like hallucinations. At this stage, ideas may intuitively appear that contribute to the successful solution of a particular problem.

Now it cannot be used as a sleeping pill; that is, doing exercises when you do not fall asleep because the indispensable condition for rest is not fulfilled, which must be done endlessly, because in fact it becomes an attempt to sleep, and the effort does not lead to relaxation or sleep. This is why it is recommended to do relaxation exercises at other times of the day and for the sole purpose of learning to recognize when you are stressed.

The importance of deep sleep for the body

Diaphragmatic breathing: Breathing is also a good method of relaxation. Sleep is associated with deep, regular and abdominal breathing, which can lead to physiological deactivation. Thoughts and concerns for our cocaine detox team is a major component of insomnia. The following classes were identified: solving daily problems, staying awake, general problems, noise in the house, and other room conditions.

Second stage. At this stage, the so-called “sleep spindles” appear - the sigma rhythm, which is a rapid alpha rhythm (12-14-20 Hz). With the appearance of “sleep spindles”, consciousness is switched off; during pauses between spindles (and they occur approximately 2-5 times per minute), it is easy to wake up a person. Perception thresholds increase. The most sensitive analyzer is auditory (the mother wakes up to the cry of the child, each person wakes up to the naming of his name).

The problem with thought control is that it is ironic or paradoxical because there is a process of looking for alternative thoughts and the other is checking if it is achieved or if it fails and that causes the thought to increase its frequency. When we want to not think about something, we think about something else, and we understand it, but suddenly we realize that we have achieved it, and that we did not think about it, with which the thought becomes real again. The desire to stop thinking about something has been shown to increase the frequency of that thought.

Third stage. It is characterized by all the features of the second stage, including the presence of "sleep spindles", to which slow high-amplitude delta oscillations (2 Hz) are added.

Stage 4 of slow-wave sleep, deep sleep. This is the deepest sleep. Delta oscillations (2 Hz) predominate.

Video: Somnologist R. Buzunov about interesting facts about sleep

Create a series of pre-sleep routines that activate conditioning, which automatically leads to the calmness needed for sleep. For example: lock the door with the key, turn off the gas, brush your teeth, set the alarm and complete all the tasks necessary for that moment of the night, always do them in the same order. Set a fixed time to get out of bed and go to bed. You should get up around the same time every morning, including weekends. If you think you have to get up later on the weekends, do it no later than an hour later. Control physiological variables, don't go to bed hungry, thirsty, want to pee, etc. Avoid drinking alcoholic beverages. Alcohol can be a short-term remedy. At first it has a calming effect, but then it causes insomnia and restless sleep, shallow sleep accompanied by night awakenings. Calculate the time it takes to fall asleep. If it takes five minutes or less, it's likely you won't get any sleep. Five to twenty minutes is normal. And if it takes longer, it means you're not ready to sleep yet. A hot bath is another way to relax before bed. Warm water relaxes and creates a feeling of well-being. Take warm milk before going to bed. It releases tryptophan, which is a substance that induces sleep. Have a quiet lunch and do not lie down for two hours after lunch. Before going to bed, do not drink chocolate or large amounts of sugar. Avoid drinking excess liquids. If you wake up in the middle of the night, don't eat anything, or you may start waking up at the same time usually, feeling hungry. Control noise, light and temperature in the room. If you can't sleep, get up and come back when you are asleep. When you get into bed, you should turn off the lights in the room with the intention of going to sleep immediately. If you can't fall asleep in one sitting, about 10 minutes, get up and go to another room. Engage in quiet activities until you feel numb, at which time return to the bedroom to sleep. Make sure the bed is large enough that the mattress and mattress are firm and comfortable enough so that the bedding is not too thin, excessive or irritating. Try natural remedies such as: lemon balm, Roman chamomile, valerian, passionflower, lavender, passionflower, etc. don't go to bed while you're awake. Do not use the bedroom for activities other than sleeping. The only exception to this rule is sex. Don't use your sleep time to think about your problems.

• Exercise regularly, but do it during the day.
• Avoid doing this hours before bed.
• A daily walk before dinner is recommended.

Sleep is a transient and reversible state that alternates with wakefulness.

The third and fourth stages are often combined under the name delta sleep. At this time, it is very difficult to wake a person; 80% of dreams occur, and it is at this stage that sleepwalking and nightmares are possible, but the person remembers almost none of this. The first four slow-wave stages of sleep normally occupy 75-80% of the total sleep period.

It is an active process involving multiple and complex physiological and behavioral mechanisms in various systems and regions of the central nervous system. In addition, this stage is also characterized as the stage in which dreams occur. The distribution of sleep stages at night can be altered by several factors such as: age, circadian rhythm, room temperature, drug intake, or certain diseases.

Sleep mode has several functions. The simplest hypothesis is that sleep is designed to restore the body's possible energy flow established during wakefulness. Do not drink alcohol or coffee, some teas and soft drinks before bed. If you haven't slept much in the past nights, avoid sleeping during the day. Don't bring trouble to bed. Perform quiet and relaxing activities in preparation for sleep. Stay physically and mentally active.

• Schedule regular bedtimes and wake-ups.
• Go to bed just before bed.
• Maintain a proper sleeping environment: clean, dark, noise-free and comfortable.
• Do not use sleeping pills without medical advice.

In the animal kingdom, it seems that the larger the animal, the fewer hours it devotes to sleep.

It is believed that slow-wave sleep is associated with the restoration of energy expenditure.

REM sleep

Rapid eye movement sleep (paradoxical sleep, rapid eye movement stage, or REM sleep for short) is the fifth stage of sleep. EEG: rapid fluctuations in electrical activity similar in value to beta waves. This resembles the waking state. At the same time (and this is paradoxical!) at this stage the person is completely immobile due to a sharp drop in muscle tone. However, the eyeballs very often and periodically make quick movements under closed eyelids. There is a clear connection between REM and dreams. If at this time you wake up the sleeping person, then in 90% of cases you can hear a story about a vivid dream.

An example is the African elephant, the largest land animal. In the wild, it sleeps an average of two hours a day and often goes nearly two days without sleep. The study is unprecedented for emerging from captivity. Researchers observed two African elephant matriarchs in Botswana's Chobe National Park for 35 days. They provided the elephants with a sleep sensor in the trunk and a collar that allowed them to identify their sleeping position.

In their natural habitat, elephants sleep only two hours a day, the least amount of sleep among mammals, says Paul Menger of the University of the Witwatersrand in South Africa. They don't have time to dream, the researchers contacted. They remain awake for up to 46 hours, traveling long distances during these periods.

The REM sleep phase lengthens from cycle to cycle, and the depth of sleep decreases. REM sleep is more difficult to interrupt than slow sleep, although it is REM sleep that is closer to the threshold of wakefulness. Interruption of REM sleep causes more severe mental disorders compared to non-REM sleep disorders. Some of the interrupted REM sleep must be replenished in subsequent cycles.

Predators constantly harass elephants, who must always be on guard. Another reason for sleeping several hours is the amount of food you eat. Herbivores that eat low-calorie foods need to spend more time chewing in order to consume energy from their food and not need as much time to digest. It is not surprising that the giraffe, like the elephant, sleeps very little.

Already, the number of hours of sleep is universally decreasing among mammals depending on the density of neurons per cortical area. The lower the density of neurons in the brain, the less the animal needs to sleep. Neurons grow, density per area falls, and animals sleep less. More time for feeding allows you to increase the growth of evolution.

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

Those who are blind from birth dream of sounds and sensations, they do not have REM.

How much sleep a person needs is inextricably linked with the concept of sleep phases. The sleep phases of any person alternate alternately, replacing each other, and there should be a certain number of such alternations. Otherwise, the body will not receive all the necessary time to restore internal structures, as well as to structure the information received during the day.

Is it possible to get enough sleep?

Sleep-inducing metabolites accumulate in the waking brain and are produced by neurons themselves. How long an animal remains awake should depend on how long it takes for the critical concentration of sleep-inducing metabolites to accumulate. The lower the density of neurons under a certain cortical surface, the slower the accumulation of metabolites should be, and the longer the animal should remain in an active state, says the neuroscientist.

That's about 7 hours of sleep a day. But this is less than the average need for 8 hours of human sleep. They are the only omnivores on the list. The goat sleeps about 5 hours a day. More than sheep, they sleep about 4 hours. Cows spend almost all day chewing and walking. About 4 hours of sleep remain.

The sleep phases must be fully completed, thus forming a complete cycle of night rest. Moreover, depending on nature, a person can get enough sleep in a greater or lesser number of such cycles.

Let's take a closer look at the sleep phases themselves, which are the same for any person and can only vary slightly in time. And then we’ll talk about the full cycles of these phases to find out: how much sleep a person needs to get enough sleep. This is where the difference between two single individuals can vary dramatically.

Ever seen a horse sleep? Yes, for one hour he tires and lies. And pack about 3 hours of sleep. The same amount as a donkey. Some studies already show that the giraffe only sleeps about two hours a day. They were considered the animals that slept the least. Recent research conducted in Botswana has now linked to the largest land mammal, the African elephant.

The Greeks feared Morpheus, the god of dreams, because they believed that every night when he fell asleep, the deity could torment them by sending them terrible nightmares. Science, however, can prove that sleep is a good teacher. The American scientist's findings are the result of a series of experiments presented last month at the third International Congress of the World Federation of Sleep Research Societies. The meeting, held in the German city of Dresden, brought together leading researchers from different parts of the world. Every effort becomes a waste if the hours in the books are not accompanied by a good night's sleep.

Sleep phases

The sleep phases of any person are divided into 2 types:

• NREM sleep phase;
• REM sleep phase.

The complete passage of all phases of sleep takes from 1 hour to 1.5 hours for different people. Usually they focus on the last digit, although it is not exact. Each of us has our own total duration of sleep phases, which can vary slightly not only at different periods of life, but even during one night’s sleep.

Stages of slow-wave sleep

The slow-wave sleep phase begins from the moment you fall asleep and takes up three-quarters of the entire sleep cycle.

NREM sleep begins with the process of dozing, which smoothly flows into shallow, moderate-deep and, finally, deep sleep. In total, the slow-wave sleep phase, as you can see, consists of 4 types of sleep.

It is very important that during the slow-wave sleep phase nothing interferes with sleep. After all, it is during this phase that all the changes necessary for the health of the body occur:

• In mice, the energy spent during the day is restored;
• Restoration of various body structures occurs at the cellular level;
• The body builds protein structures - muscles, tissues of internal organs;
• Fat burning occurs (if you eat properly during the day, especially in the evening);
• The necessary hormones are released, primarily growth hormone and melatonin;
• The body prepares for the next day.

If the slow-wave sleep phase is often disturbed, then such interrupted sleep leads to the fact that in the morning a person feels tired, physically weak, lacks energy and is overwhelmed. True, the cause of all these problems may be not only poor sleep conditions in the slow phase, but also a general lack of these slow phases of sleep, which will be discussed below.

Scientists believe that the maximum effectiveness of slow-wave sleep occurs before 4 am. Moreover, in each new cycle, the proportion of slow-wave sleep phases gradually decreases, giving way to REM sleep phases.

After 4 o'clock in the morning, the phases of slow-wave sleep almost do not appear. Therefore, if you feel a lack of strength and energy every morning, perhaps it’s due to going to bed late, and therefore the body does not have enough time for all slow phases of sleep to recover.

REM sleep phases

The REM sleep phase occupies a relatively small proportion of the sleep cycle - only one quarter. But this does not make it lose its significance.

During REM sleep, the body:

1. Processes and sorts absolutely all information received during the day;
2. Restores the energy of the nervous system;
3. Prepares memory and attention for further work during the new day.

After 4 o'clock in the morning, almost all of the sleep time is allocated to the fast phase, which is associated with a rapid transition to wakefulness. The body has already prepared the physical body for work, and now it is preparing the mental sphere.

Sleep cycles. How much sleep do you need

Sleep cycles are interrelated with sleep stages. The circle of slow and fast sleep phases forms one sleep cycle. And the whole question is how many sleep cycles should there be during a person’s nightly rest.

Scientists agree that 5 sleep cycles are enough for the average person. This is why they usually talk about 7-8 hours of sleep needed to rest at night. 5 cycles of 1.5 hours each give 7.5 hours of sleep.

At the same time, there are people who sleep little. For such people, only 4 phases of sleep are enough to restore the strength and structure of the body, as well as process all the information. As a result, 6 hours of sleep (or even less) is enough for such people.

There is another group of people who need to sleep for 6 cycles, which takes about 9 hours. And there is no need to consider such people as couch potatoes. It's just that their body is built that way. If they lack at least one sleep cycle of up to 1.5 hours, then they will feel exhausted and lethargic all day.

The minimum acceptable number of sleep cycles is 4 cycles (4-6 hours long, depending on the duration of one cycle), but provided that these 4 cycles are completed before 4 am. In this case, the body will receive the minimum necessary time to recover during the phases of slow-wave sleep, and in the morning such a person will feel quite acceptable.

A person needs about 9 hours to restore the body. It all depends on the individual, as some people need a little less sleep. Every person goes through a stage of deep and shallow sleep. What is the norm of deep sleep, how long does it last, we will consider in the article.

What is deep sleep

This is a slow phase, which is longer than the fast phase. People need deep sleep, since it is responsible for the restoration of the human body and its functions. The nocturnal slow-wave dreaming phase goes through certain stages:

1. Drowsiness sets in - a person begins to fall asleep, the brain is still working in active mode. A person can see images that seem real to him. But they may be associated with problems that have accumulated during the day.

2. Falling asleep is the stage when a person turns off consciousness, although the brain still reacts to stimuli coming from the outside. It is very important that at this stage nothing wakes the person up, since he does not react sensitively to external stimuli.

3. The deep phase is a stage when the body slowly loses functions, the body relaxes, and electrical impulses weakly flow through the brain.

4. Delta is the deepest phase. At this time, the person is relaxed, the brain no longer reacts to stimuli coming from the outside. A person’s temperature decreases, and so does their breathing rate.

Scientists from all over the world are studying deep sleep. Immersion in a deep state is necessary from the point of view that it is at this stage that the restoration of the body’s cells occurs. Why is deep sleep important for a person? Scientists have proven that the immune system works better if the rest is of the required duration. The immune system allows you to resist infectious diseases, especially during peak months. How long should this dream last? Everything is individual, but on average the delta stage takes about an hour.

How to calculate deep sleep?

The delta phase begins after deep sleep. It is short-lived, taking approximately one hour. Characterized by a maximum shutdown of human consciousness. In order to wake up a sleeping person at this time, you need to make considerable efforts. If a person who was resting during delta sleep wakes up because he was woken up, he hardly orients himself in the space around him for several minutes. In the deep sleep phase, the muscular system is maximally relaxed, metabolism slows down, and body temperature decreases. For the fair sex – up to 35.6, for men – up to 34.9. The body activates protein synthesis and renews tissue cells. Hair and nails grow in this phase!

What is the norm of deep sleep per night?

Each organism is individual. Therefore, the norm of the deep sleep phase of an adult is different. How many hours should you sleep? There are people for whom a few hours of sleep is enough. For example, this was Napoleon, who slept only 4 hours a day. And Einstein needed 10 hours of proper rest to recuperate. And what’s interesting: both people were active, they left their mark on world history. If a person is forced to reduce his rest, this will negatively affect his health. He won't feel energized. On the contrary, a feeling of constant fatigue will haunt him.

Scientists from one university decided to conduct an experiment. 110 subjects took part in it. They were carefully selected because the experts were solving the problem - the subjects should never have known problems with sleep. Participants in the experiment were divided into age groups.

The result of the experiment is given in the table:

What are the consequences of a lack of deep sleep? Firstly, the body's endocrine system suffers. Somatotropic hormone is not produced, which can lead to obesity in people prone to obesity. In addition, people deprived of the phase in question suffer from apnea. This is a condition characterized by short-term respiratory arrest. The person may not breathe for up to 2 minutes. The body, experiencing this negative phenomenon, transmits an impulse to the brain that it is necessary to wake up. This is an alarm signal, the person gets up. This condition is dangerous because during it heart attacks and strokes most often occur. In the treatment of people who do not go through the phase of deep sleep, if they are overweight, there is a loss of extra pounds. It all comes from the fact that the hormone begins to be produced in the body, therefore, positive changes occur in it. As for apnea, it causes drowsiness. During the day it is dangerous if a person spends time driving. Scientists have proven that the slow phase of rest has an impact not only on physical activity, but also on the human intellect.

An interesting fact: athletes sleep more than ordinary people who do not experience strong physical exertion. 8 hours is not enough for athletes: they are present in the kingdom of Morpheus for 11-12 hours.

Scientists have proven that a full sleep has a beneficial effect on the mental activity of the brain. And the proof of this fact happened again with the experiments that were conducted on volunteers. They were given a list of words before resting. He needed to be remembered. The words were completely unrelated. Every person remembered them. As a result, it was found that those people who experienced the delta phase remembered much more words compared to those subjects who skipped this stage. In addition, the same scientists managed to find out that the deprivation of delta sleep leads to the fact that a person does not get enough sleep. In principle, this state is equivalent to a sleepless night. If the REM sleep phase is compensated by subsequent nights, then the slow wave sleep phase is unrealistic.

Thus, the norm of the deep sleep phase in the adult population takes from 30 to 70% of the entire dream, in general. In order to get good sleep, you need to follow some recommendations:

Make a special schedule of sleep and wakefulness (go to bed, get up at the same time period for several days);
load the body with exercise about an hour and a half before bedtime, but not later;
do not smoke before going to bed, do not eat, do not drink coffee, alcohol;
sleep in a well-inspected room;
sleep on a hard surface;
if there are problems with the spine, you need special equipment for sleeping.

What other signs indicate that a person does not have enough night rest?

Many people think that they slept fully. And therefore they ignore the signs of incomplete sleep that the body sends them. How important this is, for the notion that some people do not get enough sleep, here are some of them:

1. Overeating. If a person did not sleep well, he feels hungrier compared to a normal and full night's sleep. Lack of sleep activates your appetite, which leads to overeating and weight gain.

2. Deterioration of attention and coordination. If a person did not sleep well, he feels exhausted. The body's strength is devoted to restoring a normal state. Sometimes it's hard to coordinate. This condition is dangerous while driving; also, such an employee will not be praised at work for the numerous mistakes made due to violation of the rest regime.

3. Appearance. This is the most noticeable sign, since there is a visual deterioration in the general condition of the skin, hair, and nails. Bruises appear under the eyes, which do not decorate either a man or a woman. The help of a cosmetologist is required to hide imperfections in appearance. But it is better to follow the regime and sleep longer, increasing the duration of dreams.

4. Increased risk of colds and infectious diseases. A person whose sleep lasts little is weakened. There must be a certain amount of time for rest. In total it should be 8-9 hours. Therefore, if the regime is not followed, a person can easily become infected with colds transmitted by airborne droplets. These are influenza, ARVI, and other viruses that live in the external environment.

So, a normal sleep pattern is necessary for a healthy person. It allows the body to recover and increase its defenses. Limit sleeping people from negative external manifestations. Our health depends on how much we sleep.

Tags: deep sleep, how long deep sleep should last, norm of deep sleep.

Adequate rest is one of the main components of human health. For the formation, development, and normal functioning of the body, ideal conditions are created during sleep. Only during this period are beneficial hormones produced and amino acids are synthesized. There is also improvement, systematization of brain activity, and unloading of the nervous system.

To understand the processes taking place, you should study what slow and fast sleep is, what are the differences between these structural units and determine their importance for people. It is good to compare these parameters using indications from comparative tables.

Psychophysical processes occurring during sleep divide it into phases. At this time, different activity of the brain is observed, regeneration of certain organs and systems occurs.

REM sleep and slow-wave sleep have a certain relationship with each other. It changes with the transition from one cycle to the next. Constant interruption of one of the components has negative consequences.

Phase components of sleep and their order

Sleep is a definite structure; it includes several cycles that appear 4-5 times during the night. Each one is approximately 1.5 hours long. This form contains phases of slow and fast sleep.

An adult's rest begins with napping, which is the initial structural unit of the slow period. Next, three more components pass in turn. Then there comes a short period. The duration changes every cycle.

Features of slow sleep

The slow period lasts three-quarters of the duration of the rest. After falling asleep, it has the greatest length, gradually decreasing in the morning.

During a long rest, 4-5 periods are included in the cycles; this is the optimal value. It starts the process of falling asleep. In the third phase, bouts of sleepwalking may occur.

Structure

This phase is structured by periods. All of them are of great importance for a person. Each has its own characteristics, features, functions change in the process.

• nap;
• sleep spindles;
• delta sleep;
• deep delta sleep.

The first period is characterized by slow eye movement, a decrease in temperature occurs, the pulse becomes less frequent, and nervous activity stabilizes. It is at this moment that a solution to a problem that appeared during the day can come, the missing link in the semantic chain can be filled. Waking up is very easy.

In the second period, consciousness begins to switch off, the person sinks deeper into slumber. The pulse is rare, muscle relaxation occurs.

During the third stage, the heart begins to contract more frequently and more shallow respiratory oscillations occur. The flow of blood to the tissues is activated, eye movement occurs very slowly.

The last period is characterized by the greatest immersion. At such a moment, it is very difficult for people to wake up, they get up not rested, it is hard to get involved in the environment, dreams are not stored in memory. All body functions are significantly slowed down.

Signs

To understand that a person is in a phase of slow sleep, it will turn out if we compare the characteristic indicators: breathing, which becomes rare, shallow, often arrhythmic, the movement of the eyeballs first slows down, then completely disappears.

The heart rate slows down and the body temperature becomes lower. By this period, the muscles relax, the limbs do not move, and there is no physical activity.

Meaning

While in slow-wave sleep, internal organs are restored. During this time, growth hormone is released, this is especially important for children. They develop and improve all their systems over such a period.

It is important to know! During this period, substances necessary for the normal functioning of the body accumulate and amino acids are synthesized. This type of sleep is responsible for physiological rest.

Contradictions of paradoxical sleep

REM sleep is also called paradoxical because of the inconsistencies between its various manifestations and internal processes. During this period of rest, brain activity is very active, it can be even higher than during wakefulness, but at this time the person is in the process of dozing.

Muscle tone is significantly reduced, but the stage is characterized by movement of the eyeballs and twitching of the limbs. If such a rest for some reason takes a long time, upon awakening there is a feeling of exhaustion, snippets of dreams are spinning in the head.

Manifestations

The fact that a person is in the REM sleep phase can be noticed without the help of devices. There are a number of specific manifestations. These include:

Body temperature rises and heart rate increases. The brain begins to be active. During this period of rest, a unification occurs, a comparison of genetic information with acquired information occurs.

The value of the fast phase

During the period of rapid rest, the nervous system is activated. All acquired knowledge, information, relationships, and actions are processed and analyzed. Serotonin, the hormone of happiness, is produced.

During this period, the formation of the most important mental functions in children takes place. Insufficient duration of such rest may mean the rapid appearance of problems with consciousness. Programs for future human behavior are created, answers to questions that cannot be found while awake are formulated.

dreams

Dreams that come to a person in this phase are the most vivid and memorable. They are emotionally colored and dynamic. External stimuli can be intricately woven into the plot of a vision.

Visions are transformed into different symbols, images, and everyday reality. In the paradoxical phase, a person usually realizes that events are not happening in reality.

Awakening in different phases: differences

The structure of sleep is heterogeneous. All phases are distinguished by different brain activity, psychophysical activity, and regeneration of certain human systems.

It is important to know! The incompleteness of the processes causes a difficult transition to wakefulness in slow-wave sleep. When climbing quickly, the climb is easy, and the start of vigorous activity occurs without problems. But constant interruption of rest in this phase has a negative effect on the psyche.

Table: comparative characteristics of sleep phases

The parameters characterizing fast and slow sleep are shown in a comparative table. This is the basic data that helps to recognize the rest period. From one cycle to the next, the duration of the first becomes shorter, while the paradoxical one lengthens.

Indicators	Slow phase	Fast phase
Number of stages	4	1
Sleep depth	deep	surface
Having dreams	calm, poorly remembered	vivid, emotional, retained in memory
Eye movement	no or very slow	fast
Muscle tone	slightly reduced	sharply weakened
Breath	rare, stable	arrhythmic
Heartbeat	slowed down	accelerated
Body temperature	reduced	increased
Duration	75-80% rest	20-25% of sleep duration

Sleep Research: Interesting Facts

The paradox of time perception is often encountered in relation to sleep. There are times when it seems like you just closed your eyes, and several hours have already passed. The opposite also happens: it seems that you slept all night, but 30 minutes have passed.

It has been proven that the brain analyzes sounds, sorts them, and can weave them into a dream. Moreover, in some phases people can awaken if they are called by name in a whisper. The greater the biological age of a person, the shorter the duration of the paradoxical stage. In infants it exceeds the slow one.

A person spends a third of his life sleeping. If you sleep less than a quarter of a day for two weeks, the state of the body will correspond to being intoxicated. Memory will deteriorate, concentration and reaction will suffer, and problems with coordination will arise. But many geniuses practiced polyphasic rest over a long period of time, the total duration of which was no more than half the norm. At the same time, they felt cheerful, their performance improved, and discoveries were made.

Absolutely all people see dreams, but almost all of them are forgotten. Animals also dream. Not so long ago, most of humanity saw black and white dreams, but now 85% of men and women view vivid stories. The explanation for this is the creation of color television broadcasting.

Blind people are also not deprived of dreams. If the blindness is acquired, then the pictures represent what was previously seen. In congenital blindness, vision consists of sounds, smells, and sensations. They do not experience the phenomenon of rapidly moving eyes under their eyelids. These people are much more likely to have nightmares.

The longest period of wakefulness of a healthy person was the period of 11 days during which an American schoolboy did not sleep. After a head injury and brain damage, a Hungarian soldier did not take a nap for 40 years. At the same time, he felt cheerful, did not experience fatigue or discomfort.

It is important to know! Few girls who dream of a slim figure know the following fact. Systematic lack of sleep leads to excess weight gain. One of the important conditions for losing weight is sufficient sleep.

Women's deep rest is often 20 minutes longer than men's, but the latter sleep more restlessly and wake up more often. The weaker sex complains more about sleep disturbances and gets less sleep. Ladies are more susceptible to emotionally strong visions and nightmares.

Conclusion

You can’t make a choice about whether fast or slow sleep is better. Both of these components must be present in a person’s rest without fail and in the correct percentage.

Night rest is an integral part of every person’s life, since full, healthy sleep is the key to good health, normal functioning of brain activity and physical activity.

It is during this period that many necessary processes occurring in the body are restored. And all information received during the day is stored in long-term memory.

Several cycles occur during the night, each of which includes a slow and a fast phase.

It is especially important for people deep dream , since its violation leads to unpleasant consequences: drowsiness, weakness and irritability.

Every sleeper has a period of shallow and deep sleep.

Typically, falling asleep begins with a slow phase and lasts 60 minutes, ending with a fast phase. The entire cycle takes from 90 to 120 minutes.

When the next cycle is repeated, the proportion of the slow phase decreases, and the fast phase, on the contrary, increases.

Depending on the individual characteristics of people, from 4 to 6 cycles can take place per night.

They are divided into the following stages:

• First stage. It begins with a gradual immersion in a state of deep sleep, lasting from 5 to 10 minutes.
• Second stage. The stage of light shallow sleep, occupying 55% of the total time of night rest. During this period, the brain gradually falls asleep, the heartbeat slows down, and the body temperature drops.
• Third stage. Slow-wave sleep, which accounts for less than half of the entire process. Dreams appear.
• Fourth stage. The deepest phase is delta sleep lasting 5–10 minutes. At this time, the sleeper sees about 80% of all his dreams and it is difficult to wake him up. Phenomena such as enuresis, sleepwalking, and nightmares may occur, which the person subsequently does not remember.
• Fifth stage. It is characterized by rapid, so-called paradoxical sleep, which lasts 5–10 minutes and occurs after a slow cycle. The brain is already in the same active state as when awake, but the body is still in a stationary position. Many people clearly remember their last dreams.

REM sleep

This period is also called the REM phase - “rapid eye movements”. It makes up 20-25% of the total night's rest or 1.5–2 hours. Each phase lasts from 10 to 20 minutes.

REM sleep is essential for the mind and has the following characteristics:

• the brain systematizes information, getting rid of unnecessary information;
• memory improves;
• the events of the previous day are analyzed;
• body temperature rises;
• heart rate increases.

The REM phase occurs for a short time (3 – 5 times throughout the night).

NREM sleep

At this stage, the muscles begin to relax, breathing evens out, blood pressure decreases, and the brain is not so susceptible to various irritants. Renewal processes occur in the body. Such rest promotes the production of hormones, thanks to which muscles and tissues are restored.

NREM sleep is divided into several stages:

• Nap. The sleep phase begins. Despite the fact that a person is half asleep, the brain is actively working, trying to solve daytime problems. Therefore, dreams are often connected with real life, and a person is able to find answers to questions that he could not find during the day.
• Falling asleep. During this period, consciousness begins to gradually turn off, but the brain still has an increased threshold of perception, so even a small rustle can wake a person.
• Deep sleep stage. The body calms down, all functions gradually subside, but the brain is still sensitive to external sounds.
• Delta sleep. Muscles are relaxed, the brain does not respond to various noises, breathing slows down.

Another name for the slow phase is orthodox sleep. It is needed to restore vital functions and smooth functioning of the body.

How long should deep sleep last?

Each person has their own individual norm. Some people sleep little, others a lot.

However, if you reduce your usual rate of nightly rest, then, most likely, irritability and fatigue will appear in the morning.

Scientists at the University of Surrey conducted a study of deep sleep. It turned out that in young people it is much longer than in older people.

The effect of sleep on the body

Scientists began to experiment with sleep in the 70s of the last century. According to the results of a study at Stanford University, in which athletes took part, a dependence of mental and physical activity indicators on the duration of delta sleep was recorded.

As it turned out, with longer than usual, orthodox sleep, the level of endurance and productivity increased significantly.

What is the reason for such changes?

The fact is that at this time self-healing of tissues and organs occurs, the functioning of the immune system improves, and the aging process slows down.

Increasing delta sleep time

An interesting fact is that people are able to regulate the duration of their sleep.

The norm for deep sleep for adults is 7–8 hours.

• strictly follow the regime of falling asleep and waking up;
• Before a night's rest, you should not eat, drink energy drinks, smoke, or drink alcohol (shortly before bedtime, you can drink kefir or eat an apple);
• physical activity no later than two hours before bedtime;
• relax in a comfortable room (in a well-ventilated room, complete silence and absence of light);

Following these tips will help normalize your sleep schedule and ensure optimal sleep duration.

Causes of sleep disturbances

Losing sleep for a few nights usually does not have any serious consequences. But if sleep problems persist for quite a long time, then the reasons may be:

• psycho-emotional stress;
• chronic stress;
• mental illness;
• diseases of internal organs;
• drinking alcohol or taking medications;
• lack of day and night routine;
• traumatic injuries.

However, most often the reason for difficulty falling asleep is the emotional component of people's lives.

In any case, you should understand the causes of such troubles, get rid of them and establish a regime.

Emotional disorders and night rest

People with mental disorders are unable to sleep due to increased anxiety and depression.

Sometimes intrasomnic and post-somnic problems may appear.

As for patients with major depression, when they get up early in the morning, they are immediately immersed in their negative thoughts, which do not leave them throughout the day and reach a maximum closer to the night, because of this the process of falling asleep is disrupted.

When hereditary causes of this condition are identified, narcolepsy is diagnosed, requiring special treatment.

Discovery of delta sleep peptide

In the 70s, experiments were carried out on rabbits in Switzerland. As a result of experiments, scientists discovered substances called delta sleep peptides, which can influence the human brain. These components were isolated from the blood of rabbits while they were in deep sleep.

The benefits of such substances are as follows:

• mechanisms that protect a person from stress are activated;
• the aging period is delayed due to the antioxidant properties of peptides;
• the growth of cancerous tumors slows down;
• alcohol dependence decreases;
• convulsions are reduced and the time of epileptic seizures is reduced;
• used as an anesthetic.

How to increase delta sleep period

After conducting a series of experiments aimed at studying the relationship between physical activity and deep sleep, it turned out that daytime training does not have a significant effect on sleep duration. But evening classes showed a positive effect:

• total sleep duration increased by 36 minutes;
• the time to fall asleep has been reduced;
• the deep phase lengthened from 1.5 to 2 hours.

When mental tasks were introduced in the evening hours (tests, logic exercises), changes were also observed:

• productive sleep increased;
• the second cycle lengthened;
• The activity of activating systems has increased.