Fast and slow sleep phases - characteristics and their effects on the human body

People have always been interested in the nature of sleep, because a person gives a third of his life to this physiological state. This is a cyclical phenomenon. For 7-8 hours of rest, 4-5 cycles pass, including two phases of sleep: fast and slow, each of which can be calculated. How long each stage lasts, and what value it carries for the human body, let's try to figure it out.

What are sleep phases

For many centuries, researchers have been studying the physiology of sleep. In the last century, scientists were able to record the bioelectrical oscillations that occur in the cerebral cortex during falling asleep. They learned that it is a cyclical process that has different phases that follow each other. An electroencephalogram is taken using special sensors attached to a person’s head. When the subject is asleep, the devices first record slow oscillations, which subsequently become frequent, then slow down again: there is a change in the phases of the dream: fast and slow.

fast phase

Sleep cycles follow one after another. During a night's rest, a fast phase follows a slow one. At this time, the heart rate and body temperature increase, the eyeballs move sharply and quickly, breathing becomes frequent. The brain works very actively, so a person sees a lot of dreams. The phase of REM sleep activates the work of all internal organs, relaxes the muscles. If a person is awakened, then he will be able to tell the dream in detail, because during this period the brain processes the information received during the day, there is an exchange between the subconscious and consciousness.

slow phase

Fluctuations on the electroencephalogram of a slow rhythm are divided into 3 stages:

1. Drowsiness. Breathing and other reactions slow down, consciousness floats away, different images appear, but the person still reacts to the surrounding reality. At this stage, solutions to problems often come, insights, ideas appear.
2. Deep sleep. There is a blackout of consciousness. Heart rate and body temperature decrease. During this period, the dreamer is easy to wake up.
3. Deep dream. It is difficult to wake a person at this stage. In the body, there is an active production of growth hormone, the work of internal organs is regulated, and tissue regeneration occurs. At this stage, a person may have nightmares.

Sleep sequence

In a healthy adult, the stages of dreaming always pass in the same sequence: 1 slow phase (drowsiness), then 2,3 and 4, then the reverse order, 4, 3 and 2, and then REM sleep. Together they form one cycle, repeating 4-5 times in one night. The duration of the two stages of dreaming can vary. In the first cycle, the deep sleep phase is very short, and in the last stage it may not be at all. The sequence and duration of the stages can be influenced by the emotional factor.

Deep dream

Unlike REM sleep, the deep phase has a longer duration. It is also called orthodox or slow wave. Scientists suggest that this condition is responsible for restoring energy costs and strengthening the body's defense functions. Studies have shown that the onset of the slow wave phase divides the brain into active and passive regions.

In the absence of a dream, the areas responsible for conscious actions, perception, and thinking are turned off. Although during the deep phase, heart rate and brain activity decrease, catabolism slows down, however, memory scrolls through already learned actions, as evidenced by external signs:

• twitching of the limbs;
• a special order of breathing;
• reproduction of different sounds.

Duration

Each person has an individual rate of delta sleep (deep phase). Some people need 4 hours of rest, while others need 10 to feel normal. In an adult, the deep phase takes from 75 to 80% of the total sleep time. With the onset of old age, this duration decreases. The less delta sleep, the faster the aging of the body. To increase its duration, you must:

• create a more efficient wake/rest schedule;
• before a night's rest for a couple of hours to give the body physical activity;
• do not drink coffee, alcohol, energy drinks, do not smoke and do not overeat shortly before the end of wakefulness;
• sleep in a ventilated room in the absence of light and extraneous sounds.

stages

The structure of sleep in the deep phase is heterogeneous and consists of four non-rem phases:

1. In the first episode, there is a memorization and understanding of the difficulties that were during the day. At the stage of drowsiness, the brain is looking for a solution to the problems that have arisen during wakefulness.
2. The second phase is also called "sleep spindles". Muscle movements, breathing and heart rate slow down. The activity of the brain gradually fades, but there may be brief moments of special hearing acuity.
3. Delta sleep, in which there is a change from a superficial stage to a very deep one. Lasts only 10-15 minutes.
4. Strong deep delta sleep. It is considered the most significant, because throughout the entire period the brain reconstructs the ability to work. The fourth phase is distinguished by the fact that it is very difficult to wake a sleeping person.

REM sleep

REM (rapid eye movement) - phase or from the English rem-sleep is distinguished by increased work of the cerebral hemispheres. The biggest difference is the rapid rotation of the eyeballs. Other characteristics of the fast phase:

• continuous movement of the organs of the visual system;
• vivid dreams are brightly painted, filled with movement;
• independent awakening is favorable, gives good health, energy;
• body temperature rises due to a vigorous metabolism and a strong rush of blood.

Duration

After falling asleep, a person spends most of the time in the slow phase, and REM sleep lasts from 5 to 10 minutes. In the morning, the ratio of the stages changes. The periods of GD become longer, and the periods of deep GD become shorter, after which the person wakes up. The fast stage is much more important, so if it is interrupted artificially, it will adversely affect the emotional state. A person will be drowsy throughout the day.

stages

REM sleep, also called REM sleep, is the fifth stage of dreaming. Although the person is completely immobile due to the complete lack of muscle activity, the state resembles wakefulness. Eyeballs under closed eyelids periodically make quick movements. From the 4 stages of slow sleep, a person returns to the second, after which the REM phase begins, which ends the cycle.

The value of sleep by the hour - table

How much a person needs to sleep is impossible to say for sure. This indicator depends on individual characteristics, age, sleep disturbance and daily routine. A baby may need 10 hours to restore the body, and a schoolboy - 7. The average duration of sleep, according to experts, varies from 8 to 10 hours. When a person correctly alternates fast and slow sleep, then even in a short period, every cell in the body is restored. The best time to rest is before midnight. Consider the efficiency of sleep by hours in the table:

The best time to wake up

If we turn to the dream value table, we can see that the time from 4 to 6 in the morning brings less benefit for rest. This period is the best for awakening. At this time, the sun rises, the body is filled with energy, the mind is as pure and clear as possible. If you constantly wake up with the dawn, then fatigue and illness will not be terrible, and you can do much more in a day than after a late rise.

What is the best time to wake up

The physiology of sleep is such that all stages of rest are important for a person. It is desirable that 4-5 complete cycles of 1.5-2 hours pass per night. The best time to get up is different for everyone. For example, it is better for owls to wake up from 8 to 10 in the morning, and larks get up at 5-6 o'clock. As for the dream stage, everything is ambiguous here. From the standpoint of the structure and classification of phases, the best time to wake up is those two or three minutes that fall at the end of one cycle and the beginning of another.

How to wake up in REM sleep

Since the cycles are repeated, and the duration of the slow phase increases to 70% of the night's rest, it is desirable to catch the end of the REM stage in order to wake up. It is difficult to calculate this time, but in order to make your life easier, it is advisable to find the motivation to get up early in the morning. To do this, you need to learn immediately after waking up not to lie in bed idle, but to do breathing exercises. It will saturate the brain with oxygen, activate the metabolism, and give positive energy for the whole day.

How to calculate sleep phases

Self-calculation is difficult. You can find circadian rhythm calculators on the Internet, but this method also has a drawback. This innovation is based on averages, does not take into account the individual characteristics of the body. The most reliable method of calculation is to contact specialized centers and laboratories, where doctors, by connecting devices to the head, will determine the exact data on the signals and vibrations of the brain.

You can independently calculate the stages of a person’s sleep like this. The duration (average) of the slow stage is 120 minutes, and the fast stage is 20 minutes. From the moment you go to bed, count 3-4 such periods and set the alarm so that the wake-up time falls within a given period of time. If you go to bed at the beginning of the night, for example, at 22:00, then feel free to plan to wake up between 04:40 and 05:00. If this is too early for you, then the next stage for a proper ascent will be between 07:00 and 07:20.

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