Insomnia and fight against it → Phases of sleep
It would seem that sleep can only be sound or not. In fact, there is a concept of “sleep phase” .
Perhaps many of you have noted that the day before you went to bed rather late, but in the morning you woke up early and feel very cheerful. And sometimes, on the contrary, they went to bed early, got up late, and it feels like they did not sleep at all. And the whole point is just in the phases of sleep.
Experts distinguish two types of sleep: fast and slow. REM sleep is divided into 4 more phases. Thus, we get 5 phases of sleep: four slow-wave sleep and one REM sleep.
Slow sleep
The first phase can also be called the nap phase. During this phase, the rhythm of the alpha waves decreases. They are replaced by slow theta waves and delta waves. This phase is characterized by reflecting on events and problems that have arisen during the day. Drowsiness is accompanied by half-asleep dreams and hallucinations. In the first phase, intuitive solutions to a problem may arise.
The second phase of sleep is associated with the appearance of the so-called “sleep spindles” – this is an accelerated rhythm of alpha waves. Muscle activity decreases, breathing and pulse slow down. The appearance of “sleepy spindles” contributes to the gradual blackout of consciousness. Several times a minute, a person is in a state where it is very easy to wake him up. At the same time, perception improves. The most powerful analyzer is the auditory.
The third phase is transitional from the second to the fourth. During this phase, high-amplitude oscillations of delta waves are turned on.
The fourth phase is the deepest sleep. During this phase, delta fluctuations predominate. Some scientists combine the third and fourth phases into one, calling them delta sleep. It is difficult to wake a person up during this phase. It is during this phase that a person can have nightmares, talk or even walk in a dream. However, a person, as a rule, does not remember any of this.
The first two phases are considered superficial, and the second two are deep. All four phases typically account for about 80% of all sleep.
REM sleep
This stage is characterized by rapid eye movements. This is the main difference between the fast phase and the slow one. The second difference is that during REM sleep, the brain is activated, the pulse quickens, but the muscles are in a completely relaxed state.
It is almost impossible to wake up a person during REM sleep, despite the fact that his state most of all resembles wakefulness.
Scientists cannot agree on what REM sleep is for. Some believe that at this time the brain organizes information. The second is that the brain, after analyzing the environment, tries to adapt to it. In a certain way, this hypothesis is confirmed by the fact that in infants, REM sleep takes about 50% of the total sleep period, in adults – up to 25%, and in the elderly about 15%.
However, for ordinary people, something else is important. It is during REM sleep that we see the most vivid dreams. Other phases of sleep also contain dreams, but they are not so clear and we, as a rule, do not remember them. Experts also say that you will only be able to remember a dream if you wake up directly in REM sleep.
As you can see , eight hours of sleep is not a panacea. This is just an average number of hours of sleep. Only specialists can determine exactly how long a particular person’s sleep phase lasts. However, you yourself can also find out, through experiments, how much time it takes for you. If you manage to wake up cheerful and cheerful, despite the fact that you fell asleep late, then you managed to wake up in REM sleep. Thus, you can calculate how long it took your body to go through all the phases of sleep.