How many hours of sleep a night – briefly and clearly


A sound, healthy sleep is promoted by a comfortable bed, a clear conscience and the absence of the Internet. Overcoming the temptation to finish important tasks, finish watching a movie, finish reading an article, you will give yourself precious minutes of rest. There will be a new day for business! It will begin with a burst of energy and positivity, provided that rest was sufficient for recovery.

Why Sleep is So Important

Our wise ancestors said: it’s better to be hungry than sleep deprived. This postulate is confirmed by scientific research in different countries. The main conclusion reached by scientists is that the duration of sleep determines the length of human life.

Chronic sleep deprivation has a negative effect on the body and contributes to the development of serious diseases:

  • weakening of the cardiovascular system;
  • Brain deterioration – the emergence of a tendency to dementia, poor mood and performance;
  • risk of developing type 2 diabetes;
  • overweight;
  • decrease in immunity, resistance to colds and viral diseases. In case a prophylactic vaccination has been given, its effectiveness decreases.

Each of these phenomena can reduce the quality of life and lead to serious health problems.

The concept of deep sleep

Human sleep is a cyclical process, during a night’s rest its two phases alternate. They are conventionally called slow and fast. The duration of slow phase sleep for an adult lasts 1.5-2 hours. This is followed by a period of rapid sleep, which lasts 5-10 minutes. During the night, there are 4-5 cycles. The closer a person is to waking up, the shorter the phase of slow sleep and the longer the phase of fast sleep.

It turns out that with 8 hours of sleep, the duration of slow sleep is 6.5 hours. In the structure of sleep, it is the slow phase that ensures deep sleep. It consists of 4 stages:

  • Light sleep, falling asleep, and drowsiness are the borderline state between dreaming and dreaming. One’s muscles are relaxed, consciousness is confused, and one can talk to it, but not count on full adequacy.
  • Falling asleep, immersed in sleep is responsive, capable of being interrupted by the slightest external influence. But gradually the heart slows its rhythm, body temperature drops, and consciousness shuts down.
  • Deepening sleep. Medics call this stage delta sleep.
  • Dipping into the slow delta sleep stage, a mode of minimal energy consumption. The muscles of the body are completely relaxed, the pulse and rhythm of breathing are slowed, and the brain is disconnected from the outside world. A deeply asleep person is visited by dreams. It is difficult to awaken him, and if one succeeds, the awakened person will be disoriented and “broken.

The deep sleep phase is extremely important because during this period, processes take place to carry out a person’s complete rest:

  • the human body relaxes due to a decrease in the activity of the sympathetic nervous system;
  • regenerative processes take place;
  • metabolic processes slow down;
  • the pulse becomes rare;
  • anabolic hormones – growth hormone and testosterone – are produced;
  • production of stress hormones – adrenaline, cortisol, etc. – decreases.

If slow sleep is necessary for the full functioning of the body, then the phase of fast sleep restores mental functions. Therefore, sound productive sleep is considered a universal cure for all diseases.

How long does a person need to sleep in order to get enough sleep?

The number of hours of night sleep depends on the age of the person. And lack of sleep, fraught with weariness, fatigue, sleepiness is no less dangerous than oversleeping. Those who like to sleep for a long time more often suffer from cardiovascular diseases. The unforgiving statistics are as follows: 12% of people who sleep less than 6 hours a day, can die before the deadline, and among those who sleep more than 9 hours – the risk of dying before the deadline reaches 30%!

The optimal duration of sleep for an adult between the ages of 25 and 65 is 7 to 9 hours. Individual characteristics of the body will suggest the most correct figure, but within these two hours.

For other age categories the picture is as follows:

  • Babies up to 3 months should sleep up to 17 hours a night;
  • Infants up to a year old need 12 to 15 hours of sleep;
  • Toddlers under 2 years of age need 12 to 14 hours of sleep;
  • Preschoolers 3 to 5 years old need 10 to 13 hours of sleep;
  • Junior high school students up to 13 years old need 9 – 11 hours for a good rest;
  • Teenagers aged 14-17 need 8-10 hours of sleep;
  • Boys and girls 18 to 25 years old require 7 to 9 hours of sleep, as do adults;
  • A group of seniors over the age of 65 needs 7 to 8 hours of rest each night.

All in all, we spend about a third of our lives sleeping!

Healthy Sleep Rules

To use hours of sleep productively and efficiently, it is enough to follow some simple rules, and even better to make them a norm of life – a good habit that keeps you beautiful, healthy and stimulated.

  • Go to bed not on the day you plan to wake up. Ideally, an adult is defined by the time from 10 p.m. to 11 p.m. A developed reflex to go to bed at the same time promotes fast and easy falling asleep.
  • On weekends you can sleep longer, but not more than 1-2 hours, “to spare” sleep does not work. This time you will spend on a long night falling asleep.
  • Only in the complete darkness at night produces melatonin, the hormone that helps the body to recover. Do not use nightlights, and the dense curtains, covering the moonlight and street lamps, will be very helpful.
  • Avoid late dinners, let 2-3 hours pass after the meal to complete the process of digestion, and nothing would distract you from sleep.
  • Fresh air works like a sleeping pill, so ventilate the room before going to bed.
  • The temperature in the bedroom should not be higher than 18-20oC, if it is too cool – cover up warmer or wear pajamas.
  • Form an individual bedtime ritual. Its program should not include arousing moments in the form of watching “nightmares” on TV or reading the news feed on the tablet. Flip through your favorite book, talk on the phone with a loved one, talk to your children or pets.
  • Find the best mattress, pillow, and blanket for you.
  • Replace your old bed with a new modern model.
  • If you sleep on a folding sofa or chair, buy a quality topper.

Psychologists do not recommend installing a TV in the bedroom. Consider this advice! A good habit before going to bed would be a cup of herbal soothing tea, a glass of warm milk with a teaspoon of honey, a relaxing bath.

Causes of insomnia

Sleep disorders cause a lot of damage to the body, so it is important to identify the cause of insomnia as early as possible and eliminate it. The most dangerous is considered to be prolonged insomnia lasting more than 3 months. It can provoke a complex of reasons and without the help of specialists in this situation can not do.

Doctors consider psychosocial stress, depression, vigorous brain activity, non-compliance with sleep and wakefulness regime, thoughtless intake of stimulants (coffee, alcohol and drugs) to be the main provocateurs of insomnia.

The elderly, patients suffering from endocrine, infectious and neurological diseases are at risk of developing insomnia. It is not always possible to eliminate the somatic causes of the most important physiological process, but by following good sleep hygiene, insomnia can be relieved.

Is it useful to sleep during the day?

For a small person, a nap during the day is a must. For a big one, napping during the day is not forbidden. People who are able to rest in the middle of the day, improves memory and increases concentration. Naps will restore strength, reduce the likelihood of depression, cardiovascular problems and will not provoke insomnia.

But do not get carried away, a long nap is not useful. It disrupts the rhythm of life, the endocrine system and leads to insomnia at night. The rest of the day should be:

  • no longer than 20-30 minutes between 13 and 15 o’clock in the afternoon;
  • on a comfortable sleeping place (sofa, couch, chair);
  • without loud sounds, bright lights and other irritating factors.

Experienced lovers of afternoon naps recommend drinking a cup of coffee or tea before resting; the drink will take effect in 20 minutes and it will be easier to wake up. After a day’s rest is useful a little warm-up for the muscles.

How to learn to wake up early

For “skylarks” this question is irrelevant, they wake up easily and do not have the agony of a long waking up. There are people “pigeons” for whom the early rise is also not a difficult task. The real sufferers from early waking “owls”. For them, a few helpful tips:

  • Go to bed not too late and not after a hearty dinner with a tablet;
  • Wake up with the first alarm, do not delay getting up for another 5 minutes;
  • Turn on upbeat music and as much light as possible;
  • drink a glass of water;
  • do pleasant, unencumbered exercise with rhythmic music;
  • wash your face with cool water and, if you are able, take a contrast shower;
  • energize the body with a hearty breakfast!

Everyone who decides to change the rhythm of life is convinced of the benefits of an early rise. Those who rise early have a better chance of getting a pleasant surprise from fate.

Rising early restores the strength that wasted the day. Like the best cosmetologist, it smoothes out wrinkles, removes traces of daytime fatigue from the face, brings rest to the muscles and replenishes energy. It is said that the night stars are the holes in the floor of Heaven. Their rays bring streams of universal wisdom to the sleeping man, so at night we become kinder and brighter. Sleeping hours are priceless!

The sleep phase-what it is and its effects

“When I sleep, I know no fear, no hope, no toil, no bliss. Thanks to whoever invented sleep. It is a single watch that equals the shepherd and the king, the fool and the wise man.” So wrote the great Cervantes.

Sleep is the third most important element for humans, along with food and water. When we sleep, we rest, but our brain continues to work. How does it work? Let’s talk below about why humans need sleep in the first place, how the brain works during sleep, and how chronic lack of sleep affects our well-being.

Brain, sleep and hormones

The human body is amazing! If you carefully study our life processes that go on in the body, you’ll be amazed at how interconnected and rationally arranged everything is.

Why do some people fall asleep at the end of the day while others are awake and cheerful? Our sleep is controlled by our biological clock, and its center is in the hypothalamus (part of the brain). It is the one that makes the body prepare for sleep. After about 8 p.m., our body temperature automatically goes down, and our nervous system calms down.

It is known that there are two systems in the body: sympathetic and parasympathetic. The sympathetic one is responsible for vigor and energy, activity, the parasympathetic one – for calmness, relaxation and inhibition. At different times of the day one of these systems plays the leading role. Every living being has a biological clock. Animals, for example, have a biological clock that tells them when to migrate or hibernate.

Our bodies respond to the dark time of day. At night, the hormone melatonin is produced in the human body. Without it, we will age ten times faster! And we can die of a common cold …. When a person sleeps, the brain puts things in order – it erases unnecessary information, archives the necessary data. And while we sleep and, consequently, do not disturb the brain, it “adjusts” all the systems of the body.

Also sleep is necessary to cool down the brain itself. Its temperature is lowered during certain phases of sleep (we will tell you about them below). If we did not sleep, our head would simply “overheat. Everyone knows the expression – brains boil? Now you know the way out – you just need to sleep. Although, perhaps in the midst of the day, it will be difficult.

But if sleep is so important, why do some people with the onset of darkness do not want to sleep at all (hello “owls”!)? It all depends on the individual characteristics of each person. Not without reason, some are divided into “larks” and “owls. The first – rise early and go to bed early, and the latter, on the contrary, prefer a nightlife.

And a little more about hormones. If we didn’t sleep, we would eat all the time. The appetite-reducing hormone leptin is produced only during sleep. Those who don’t get enough sleep have another hormone, ghrelin, which increases appetite. The less we sleep, the more we want to eat. So, draw conclusions, those who want to lose weight.

The biological clock of most people closer to morning begins to prepare the body for awakening. The heart rate increases, the blood pressure rises, and the activity hormones cortisol and adrenaline are released. The most important factor for awakening is daylight. The skin of the eyelids is very thin, even when the eyes are closed, light penetrates through the skin to the retina and gives a signal to the brain to produce serotonin. Serotonin is a neurotransmitter of activity and energy. The brain then activates the auditory centers. We respond to the sound of the alarm clock and wake up.

Lack of sleep can affect the brain in the most negative way – reduced logical perception, reaction rate, speed of thought reactions, deteriorating health.

Sleep phases

In any person sleep is divided into two phases – fast and slow. Fast and slow phases alternate with each other, making a sleep cycle. Each cycle is about one or one and a half hours.

In the slow phase, the cells and internal structures of the body are renewed, hormones are released (we wrote about them above), and the process of energy restoration takes place. During slow sleep, your breathing is even, your eyes are still, and your muscles are relaxed.

Slow sleep is followed by a phase of fast sleep (duration: 10-20 minutes). The heart beats faster, the temperature and blood pressure rise, and the person may dream.

The effect of sleep on health

Do you remember we wrote about how the brain works while we sleep? Amazing, isn’t it? Everything is interconnected, clear and to the point. The hormone is produced, we sleep, the brain works. We don’t sleep, the hormone isn’t produced, and the brain keeps working anyway. But there’s a limit to everything…. What does lack of sleep lead to?

Weight gain. Hello from the hormones leptin and ghrelin! Less sleep, more food.

Chronic fatigue. We don’t get enough sleep, are perpetually tired, go to work again, complete tasks, and dream of weekends to finally get some sleep.

We look bad. We get bags under our eyes, bad skin tone and premature skin aging.

Our immune system goes down. While we sleep, proteins are synthesized in blood – cytokines (these are battle rockets of our immune system). Accordingly, less sleep means less cytokines – weaker immunity.

Attention and reaction rate decrease. You haven’t given your brain a rest! Where will attention come from? Alas, other cognitive functions also suffer – memory, thinking. Everyone remembers how the lack of sleep begins to “dumb”?

Sleep disorders

The most common sleep disorder is insomnia or insomnia. A person may have trouble falling asleep, there may be intermittent, shallow sleep. The causes of insomnia can be many. If you are suffering from insomnia, do not neglect your health, be aware of the problems that may arise from lack of sleep, it is better to see a neurologist or somnologist.

Apnea is another common sleep disorder. Apnoea (breathlessness) and snoring can really ruin the life of not only the person who suffers from it, but also those around him. Try to fall asleep when a small diesel generator starts working in the bedroom every night. Even in a healthy person, the airway can become blocked for a few seconds during sleep. With apnoea, the airway closes for more than ten seconds, there is a lack of oxygen, and the brain gives the command to wake up.

Restless legs syndrome – with this disorder, the person’s arms and legs are constantly twitching in their sleep (every twenty to forty seconds). Sleep becomes shallow, the person is chronically sleep-deprived, hence the other problems.

Parasomnia – the brain secretes a special hormone during sleep that paralyzes our muscular system so that we don’t repeat the movements we make in a dream. If this blockage does not work completely, parasomnia occurs. This is a disorder of sleep behavior. The person can get up, walk, talk, and sometimes show aggression. In the morning, however, the person suffering from parasomnia remembers nothing. It often happens in children and adolescents because their nervous system is not yet fully formed.

Sleeping problems in children can be the cause of other more unpleasant situations, or be a sign of neurological disorders. Neuropsychological diagnostics, a very interesting and popular field among specialists, helps to detect this. If you are interested in this field, we can recommend our course – “Psychological and Pedagogical Support of the Educational Process in a Preschool Educational Institution. Neuropsychological diagnosis and correction in childhood.

Hypersomnia, daytime sleepiness – with this disorder a person constantly wants to sleep during the day. It can even be called not a sleep disorder, but a wakefulness disorder, because a person with hypersomnia has no problems falling asleep. He sleeps normally at night (although in some cases daytime sleepiness may be provoked by apnoea), but during the day he is also drawn to sleep.

Narcolepsy – a person suffering from narcolepsy may involuntarily fall asleep during the day. And it does not depend on whether he slept at night or not. It is an uncontrollable sleep attack.

How much sleep?

Somnologists (sleep experts) stick to the fact that it is necessary to sleep for at least eight hours, if we are talking about an adult. The younger the age, the more sleep time may be needed. Think of infants who sleep twelve to fifteen hours a day. Up to the age of eighteen, a person needs ten or more hours of sleep. It is only as an adult that eight hours of sleep are allowed.

Some prominent historical figures adhered to polyphasic sleep. This is sleep in which a person sleeps for several periods. For example, four half-hour naps every six hours. Some people only needed four hours of sleep a night at all. Yes, each of us is special, some are “night owls,” some are “larks,” some need eight hours of sleep, and some are enough for five hours.

But we still do not recommend experimenting with your own sleep and try to sleep for at least eight hours a night.

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