What phases is our night divided into, how many hours of sleep do we need, why is it important to teach a child to fall asleep on his own? Somnologist Mikhail Poluektov told us what important events take place in our body while we sleep.
Psychologies: We imagine our night’s sleep as a whole. But is it really not so?
Mikhail Poluektov: Indeed, sleep is not a homogeneous state. It is divided into time phases, which are very different from each other. There are two of them: non-REM sleep, which takes about 75% of the time, and fast sleep, about 15%. In addition, these phases of sleep change cyclically with a period of one and a half hours, that is, they are repeated 4-6 times per night.
Science is still debating why exactly 1,5 hours. There is a theory that this is an evolutionary adaptation of our body, due to the need to survive in the wild. After all, in a state of deep sleep, the animal is absolutely helpless, it can be eaten by any predator. Therefore, nature developed a mechanism by which the animal could “piece by piece” satisfy its need for rest, but periodically wake up in order to be ready to face danger.
According to another version, such an hour and a half cycle is generally characteristic of a person throughout the entire time of the day. It is known that we are able to maintain active attention for 45 minutes — that is, half of a 1,5-hour cycle (not for nothing that this is how long an academic hour lasts at universities).
The folk wisdom that children grow up in their sleep was not invented by chance — it is in this phase that almost the entire daily rate of growth hormone is released into the body.
What is the difference between REM and non-REM sleep?
They perform different functions. In scientific terms, during the slow phase of sleep, there is a pronounced slow-wave activity on the electroencephalogram. Such activity is not characteristic of the waking brain. It is believed that this part of sleep is responsible for the physical recovery of the body. When studies were conducted on the sleep of professional athletes, it turned out that the more intense their workouts, the longer their slow-wave sleep was. By the way, the folk wisdom that children grow up in their sleep was not invented by chance — it is in this phase that almost the entire daily rate of growth hormone is released into the body.
REM sleep, you guessed it, is responsible for the recovery and relaxation of the brain and psyche. However, this does not mean at all that brain activity stops at this moment. It is in the REM phase of sleep that some scientists come up with discoveries — this is a long-known phenomenon of «creative dreams». Our head continues to work on solving the tasks that were set during the day.
Those problems that seemed insoluble in the evening can lose their negative meaning during a night’s sleep, while a person can find a way out of an unpleasant situation during sleep. Therefore, the morning of the evening is really “wiser”.
In what part of sleep do we dream?
During REM sleep. Outwardly, this can be seen when the pupils under the closed eyelids begin to move in the sleeping person — as if he is following the ball while playing ping-pong. In animals, this is accompanied by whining, twitching of the paws, and children may cry or moan. All this indicates the onset of a special state — REM sleep. Interestingly, if at this moment a person is awakened, then he will most likely tell what dream he had.
Dreams usually reflect the elaboration by our consciousness of those problems that occupy a person’s thoughts during the day. During sleep, a “window” opens through which you can look into the depths of the unconscious. In patients with neurosis, dreams often reflect the cause of their disorder. Of course, in symbolic form — this is what Freud’s teaching is built on.
The secret of healthy sleep for children is not in the cyclical phases, but in how to properly put the child to sleep
There is a theory that intermittent and restless children’s sleep is due to the fact that babies do not «know how» to move from one phase to another. Can they be taught this?
Can. A child, unlike an adult, is free from social stereotypes, so his sleep is close to the natural needs of the body. He sleeps several times a day — and this is really better for health. In children, sleep cycles are shorter than in adults, in the first year of life they are about an hour. But the secret of healthy sleep for children is not in the cyclical phases, but in how to properly put the child to sleep.
Many parents do not allow the baby to learn to fall asleep in the evening on their own. They rock him in their arms, cradle him for a long time. Therefore, when the next phase of sleep comes to an end and the child, turning over on the other side, wakes up in the middle of the night, he requires the help of adults to go back to sleep. Then the parents come to the doctor and complain that the child does not sleep at night.
At what age can he be taught to fall asleep on his own?
In principle, from the first day, if you do not help, but leave to fall asleep alone. The desire to sleep at night in a child is formed from 2 months of life — this is associated with the maturation of the body’s internal clock. Before that, he can «confuse» day and night. But then you can already demand from him that he sleeps all night, and if the child “walks” at night, then the parents are already to blame.
In the first years of a child’s life, maternal sleep is often restless. As a result, after a few months, they constantly feel tired. What are the consequences of such chronic lack of sleep?
The experience of numerous generations of mothers suggests that sleep disturbance in the process of raising a child of the first year is not so terrible. It is believed that only 10% of children at this age have problems with sleep. And here we again return to the question of how important it is to teach a child to fall asleep on his own. Then his parents will be able to rest all night.
Is long but intermittent sleep really worse than short but uniform sleep?
Today, health risks are proven only for sleeping less than 6 hours. This threatens with hypertension and diabetes. Another thing is that lack of sleep is also important because it negatively affects the mental state of a person, his social functioning. Permanent lack of sleep makes a person irritable, lethargic, unable to perform their normal functions. Therefore, the main rule is to give sleep at least 7-8 hours a day.
There is a concept that you can teach yourself (through yoga or other practices) to sleep less than 6 hours and feel good. But does our body really need it?
From a physiological point of view, this is absolutely unjustified. Because the need for sleep is genetically encoded. We can teach ourselves to sleep less than our norm and even convince ourselves that we feel great. But this is self-hypnosis, because in fact the body does not have time to rest — and the harmful effects will accumulate.
If you can’t get enough sleep at night, can you compensate for this with daytime sleep?
Yes, moreover, daytime sleep helps to increase both productivity and quality of life in general. It is not for nothing that siesta is practiced in southern countries.
The time of daytime sleep can be very different — it depends on your personal biorhythms. It is comfortable for someone to doze off after dinner, and for another closer to 5-6 pm. In this matter, you need to listen not to the advice of specialists, but to the needs of your body. There is one exception — people who already have sleep disorders should not go to bed during the day, since such «oversleeping» reduces the likelihood of timely falling asleep at night.
The material was prepared as part of a series of lectures in the journal Psychologies and the lecture hall «Direct Speech».