Phases of human sleep: what is the difference between fast and slow sleep

We wish each other sweet dreams, not at all meaning dreams in the form of desserts. A sweet dream is a pleasant, light, invigorating dream, after which a person feels full of energy, easily shakes off the remnants of drowsiness and is in a good mood (this happens when the sleep phases have gone well). This includes a wish. "Good night!" - they say to each other, going to bed. The usual phrase is actually full of meaning. Let the night be calm, and nothing will interrupt your sleep, which will go through all the required phases. Then the morning will be good.

Which phase is more important?

There is no answer to this question, just like the classic one: “What came first: the chicken or the egg?” Both slow and fast sleep are necessary for our body, this is physiology. During different phases of sleep, the processes responsible for rest and restoration of vitality change. You cannot advise your enemy to experiment on himself and try to do without this or that phase. This is a time bomb; it is difficult to say in which organ such tests will come back to haunt you. Rather than fight nature, it is better to try not to disrupt the normal flow by taking care of healthy nighttime relaxation. Only in this case does a person fully rest.

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. An important function of sleep is also the restoration of the human immune system by activating the activity of T-lymphocytes, which resist viral infections and fight colds.

Stages of deep sleep

Slow is divided into four stages:

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

A short nap, often during the day, is called a nap. In science, this term means the body’s first steps toward the transition from wakefulness to falling asleep. Breathing slows down, body temperature drops, brain function slows down, and the heartbeat becomes less frequent. Here a person first begins to see dreams and daydreams that are close to reality. Soon they break away from reality and seem to live on their own. The human consciousness at this stage works in an interesting way. At this moment, a solution to a problem that the dreamer has been struggling with for a long time may come. At this stage, most likely, Dmitry Ivanovich Mendeleev dreamed of his table of chemical elements. During this period, a person hears sounds, can react to them and easily wake up. This is the first, initial stage of sleep.

If it continues, then the next stage begins. The name - sleep spindles - comes from sigma rhythms, the image of which on the encephalogram of the brain resembles spindles. The psyche of a sleeping person in this state is relaxed, the pulse is slow. Reduced muscle activity. If we talk about the immersion of consciousness, then we can figuratively say that the sleeper has immersed to an average depth.

Delta is the next stage. She was also named after the waves on the encephalogram. Delta waves, deep and slow, indicate that a person is moving into the stage of his recovery. Pulse and breathing become faster, blood flow to the muscles becomes noticeable. The energy expended during wakefulness is gradually restored.

On the encephalogram, delta waves slow down. The person is completely immersed in a sleepy state. The deep phase is coming. The slow-wave sleep phase is always accompanied by a complete loss of consciousness. A person has difficulty hearing sounds and may not respond to his name. Eye movements under the eyelids become invisible. It is important to go through this stage. If a person is woken up at this time, he will wake up broken, it will be difficult for him to cheer up. This phase is also responsible for memory. Only after resting in this state does the brain retain the ability to remember information.

What it is

NREM sleep consists of 4 stages:

1. At this stage, the person enters a state of drowsiness. He experiences half-asleep visions reminiscent of hallucinations. New ideas arise in your head, solutions to complex problems come to mind. This is because the brain continues to work. The duration of a nap is about 10 minutes.
2. The stage consists of sleep spindles. They have pauses during which they can easily be awakened. There are about 2-5 of them per minute. When they turn off consciousness, the pulse decreases, and the body temperature drops. Also at this stage, the auditory threshold of perception increases.
3. It resembles the second stage. The only difference is the presence of slow, high-amplitude delta oscillations.
4. This stage is called deep. The sleeper stops responding to sounds and smells. Occasionally he may speak or move a little. It is characterized by the manifestation of sleepwalking.

This time helps the body restore the energy spent during the day. That is why it makes up 80% of the entire night's rest.

REM sleep, or paradoxical sleep, is the fifth stage. In this state, the muscles are completely relaxed, but the brain works as it does during the day.

Start to awakening

From deep delta sleep, a person returns to sleep spindles, then the so-called REM sleep phase begins. It is also called paradoxical sleep. To the question of what sign characterizes the REM sleep phase, the answer is as follows. The body is completely relaxed, muscle tone is zero. Movement of the pupils is noticeable, breathing is uneven: sometimes fast, sometimes slow. This phase is also emotional. A person has vivid, memorable dreams.

The brain is also preparing for activity. His temperature rises, even more than when awake. The information received during the day is sorted. The one that needs to be remembered is selected. The brain plans the coming day. It’s easy to wake up in this phase, but it’s a shame to miss it: something will go wrong, an important process will be interrupted without being completed.

As a person ages, the paradoxical phase of sleep decreases.

Movement of the eyeballs is a sign of light sleep

It is also called REM - rapid eye movement, or REM - rapid eye movement. Breathing at this time is less even than in the deep sleep phase. It was this stage and its connection with dreams that was studied by American scientists Nathaniel Kleitman and Eugene Aserinsky.

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.

How long does it take to get enough sleep?

The alternation of the phases of deep and shallow sleep forms cycles. In each of them, the duration of the phases is different. When a person first falls asleep, slow-wave sleep takes longer in the cycle than fast sleep. Subsequently, this ratio changes. In the last, morning cycle, the duration of the REM sleep phase becomes longer than deep sleep. Rest is coming to an end, the body is preparing to awaken.

During the night we go through 4-5 cycles, one and a half to two hours each. Whether the person got enough sleep or not depends on whether they have all passed and how long each cycle lasts.

Of course, these values ​​are approximate. Each person may have differences from those shown in the table, but the general trend remains the same.

The duration of sleep itself also varies. Some people need 5 hours of proper sleep, while others need more than 10 hours. History contains information that some great people slept 4 hours a day or less without harm to the body. Napoleon is one of them. But this fact does not indicate genius. Some scientists generously spent more than 10 hours on such rest and were not inferior to the commander in mental agility. So there is no direct relationship between the duration of the sleepy state and mental abilities.

But with age, the need for sleep changes. Babies sleep the most in the womb: they need at least 17 hours a day.

When they are born, they sleep not much less: 14-16 hours.

From three months to a year, this figure decreases significantly: 12-15 hours.

As a little person grows up, he stays awake more and sleeps less. Teenagers sleep 8-10 hours at night. The norm for an adult is 8-9 hours. And older people rest for 7-8 hours. But these figures are approximate, like the average temperature in the hospital. True, they change more often in the direction of increase.

How to determine the best time to wake up

For good health, it is very important to wake up during the fast phase. Waking up from deep sleep threatens health problems, spoiled mood and decreased performance. You can eliminate such manifestations if you wake up every day at the end of the next cycle. There are several ways to determine how long each phase lasts and to prevent awakening during slow-wave sleep:

1. Laboratory method. It is performed using special devices that are fixed on the head to determine brain activity. Based on the data obtained, the number of hours required for quality rest and easy waking up is determined.
2. Online calculator. There are many programs online that help you count your sleep cycles. The calculators are easy to use. To calculate, you just need to enter the hour of going to bed - as a result, you will know the time required for full recovery. The disadvantage of the online calculator is that it does not take into account the individual characteristics of the body.
3. Fitness bracelet. The device does not detect phases, but it does record body movements during sleep. During the fast stage, a person tosses and turns, while during the slow stage, he is motionless. The information is displayed in the form of a graph. The main advantage of the bracelet is the alarm clock, which sounds in the right phase for a soft and easy awakening.
4. Trial and error method. You can calculate how long slow-wave sleep lasts yourself. Since a full cycle takes about two hours, and a person needs at least 4 of them, by counting the periods, you can determine the best time to wake up.

The above methods for identifying sleep stages are general, because each person has their own individual characteristics. Therefore, taking them as a basis, you need to observe the sensations: if waking up is difficult, then the onset of morning should be delayed a little or, conversely, get up earlier. Over time, everyone will be able to calculate their optimal sleep duration and wake up with ease.

Age and duration of sleep phases

Not all people have the same cycles, phases and stages. They change with age. In the first years of life, there is a change in the duration of slow and fast sleep. Changes await a person even when he reaches adulthood. The period of dozing increases, and the period of REM sleep and the period of deep sleep decrease.

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. A full sleep includes 5 complete 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.

When do you have dreams?

Scientists argue during which phases we see dreams and which ones pass without them. There are supporters of the version that dreams occur only during REM sleep and the 1st stage of slow sleep - during drowsiness. There are those who are convinced that we dream about something throughout all stages, phases and cycles. But only those that were dreamed in the REM phase will be remembered.

Neurophysiological mechanisms of phases

Previously, scientists were convinced that during sleep, all human vital organs, including the brain, fall asleep. But research in this area has refuted this version. As it turns out, when we sleep, the brain is active. Neurons of a number of brain structures are in a more active state than during wakefulness. That is, this is not a passive biological process.

How long should deep sleep last?

If we talk about the total duration of the deep sleep phase throughout the entire night's rest, then the norm directly depends on age. Youth need at least 120 minutes. For people under 55 years of age, 100 minutes a day of this phase will be enough. For people over sixty years old, the recommended duration of deep sleep is 85 minutes, and for people over this age even less - 75.

But these boundaries are not rigid. The characteristics of each person can correct these figures. The body itself will tell you the correct norm.

Deep sleep: how to increase its duration?

If a person feels that there are problems with his night's rest, that the stages of deep sleep are too short or absent, then measures must be taken to return to normal. The recommendations for this are simple and have long been known:

1. Go to bed at the same time.
2. Before going to bed, take a walk in the fresh air.
3. The bedroom needs to be ventilated. Even if the temperature outside is below zero, you can let a fresh stream of air into the house for at least half a minute.
4. Taking a warm bath means helping the body transition to sleep.
5. You need to sleep in silence and darkness, that is, in complete peace.

Such recommendations can also serve as an answer to the question of how to increase the REM sleep phase. In order for both the active and slow phases to allow you to get a good night's sleep, you need to ensure darkness, silence and a comfortable temperature in the room before going to bed, have a light dinner and relax.

Major sleep disorders

Disturbances in normal sleep can occur at any age. Most often they are associated with stress. But over the years, a person increasingly experiences problems falling asleep. It is affected by aggravated diseases and psychoneurological conditions.

Restless sleep - damage to the body

Scientists have noticed that residents of large cities sleep poorly more often. Their disturbances are expressed in frequent interruptions of the sleepy state. For this reason, the normal duration and cyclicity of stages and phases is disrupted. This cannot but affect the general condition of a person. If such cases become frequent and there is a feeling that there are real problems with sleep, you need to look for the cause.

Often such phase disturbances are caused by restless legs syndrome. If heredity is excluded, then the root of evil must be sought at the chemical and biological level. Most likely, there is not enough iron, vitamins, magnesium.

Such a version as “all diseases from nerves” cannot be ruled out. Sedatives with general rules for organizing healthy sleep will help smooth out the problem. And the doctor will tell you how to do this effectively.

Helpful Tips: How to Benefit from a Night's Sleep

Regardless of whether a man or woman has a disturbed sleep structure, or how much a person sleeps, if he does it incorrectly, then rest will not give the desired result. To improve its quality, you need to follow the following recommendations from experts:

1. Stick to a bedtime schedule. It is better to go to bed no later than 11 pm. At the same time, it is advisable to wake up no earlier than 7 am (this indicator varies from person to person).
2. Before going to bed, you need to ventilate the room. The temperature in the bedroom should not exceed 22 degrees. To improve your sleep quality, you can take an evening walk in the fresh air.
3. A few hours before rest, you should not eat food that requires a long digestion time. As a last resort, you can drink a glass of warm milk.
4. Night rest should include the period after midnight to 5 am.
5. Drinking coffee, strong tea or alcohol in the evening is strictly prohibited.
6. If a person has difficulty falling asleep, he can drink tea using soothing herbs (motherwort, valerian), or take a relaxing bath with sea salt. Aromatherapy often helps you fall asleep.
7. It is important to choose a comfortable resting position.
8. Preference should be given to orthopedic devices for rest. The mattress should be flat and hard. Do not use a high headboard.
9. The room should be quiet and dark at night.
10. After waking up, it is better to take a contrast shower or do light exercises.

A proper night's rest, respecting its structure, is the key to good health and well-being. A person wakes up rested, productive, and in a great mood. Systematic lack of sleep will lead to serious impairments in the functionality of the body, which are not easy to get rid of.

When insomnia came

This term refers to disorders associated with taking too long to fall asleep. Illnesses, chronic or age-related, postpone the moment when we surrender to Morpheus. This already leads a person into a state of nervousness. First, you need to learn to take this calmly. Counting lambs is unlikely to help in this case, but a monotonous, quiet, calm activity will bring the nervous system to a normal state. If this is reading, it won't be serious. Do not exercise before bed. There is no need to strain yourself either mentally or physically. The decision to take sleeping pills should be made together with your doctor.

When falling asleep instantly, rest is required!

If a person falls asleep as soon as he touches the pillow, then this is also not very good. Without the dozing phase, the sequence of processes is disrupted. This is the first sign that fatigue has accumulated.

There is no doubt about the importance of sleep for humans. It is equally important that the cycles, phases and stages, as well as their duration, are normal. These are essential conditions for caring for the body and maintaining health. Adequate sleep is a guarantee of physiological and psychological well-being.

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 the person’s physical fatigue. A significant amount of work done during the day may require a longer night's rest. Normal sleep is cyclical and is required by the human body at least once a day. Sleep cycles are called circadian rhythms. Every 24 hours, circadian rhythms are redefined. Light is considered the most important factor in sleep. The concentration of photodependent proteins in the body depends on its natural cycle. Typically, the circadian cycle is related to the length of daylight hours. Just before sleep occurs, a person feels drowsy, his brain activity decreases, and there is also a change in consciousness. In addition, a person who is in a sleepy state experiences a decrease in sensory sensitivity, a decrease in heart rate, yawning, and also a decrease in the secretory function of the lacrimal and salivary glands. Another physiological feature of 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.

Importance for the body

Healthy sleep is the key to vigor, good physical condition, health and energy. At this time, tissue regeneration and the production of hormones necessary for normal functioning are activated.

Lack of sleep negatively affects the functioning of the entire body, and especially the functioning of the brain. Chronic lack of sleep can lead to the following consequences:

• Memory impairment and decreased attention. If you notice that it is becoming more difficult for you to concentrate on daily tasks, then this is a symptom of lack of sleep.
• Irritability and depressed emotional state.
• Decreased immunity. During a full night's sleep, cytokines are actively produced - protein compounds necessary to fight infectious and inflammatory processes.
• Premature aging, deterioration of skin and hair.
• Increased risk of obesity and cardiovascular diseases (arterial hypertension, coronary artery disease, atherosclerosis).

How much sleep do you need

The optimal duration of night's rest is purely individual for each person. For some, 7 hours is enough for complete recovery; for others, 10 is not enough. And yet there are norms for each age group. With their help, it is easy to determine whether a person is sleeping enough:

Babies in the womb and newborns rest for 17 hours. And that's okay. During rest, their brain and body grow and develop. In babies 3-11 months old, sleep is gradually reduced to 12-15 hours. Preschoolers sleep a little less (10-13 hours). Teenagers need 8-10 hours of rest at night. Young people 17-18 years old - 7-9 hours. Adults should sleep approximately the same amount (7-9 hours). Rest for pensioners is usually reduced by 1-2 hours, and this is also normal.