Characterics of a healthy sleep

Did you know?

When we are sleeping, we are not aware of ourselves and our surroundings; however, we can detect strong sensory stimuli from the surrounding area that can awaken us.

Sleeping is one of the poorly studied processes occurring in our body. Sleep is an active process that has its own characteristic pattern, and maintaining this pattern and sleep rhythm reduces the risk of sleep disorders, mental health, and chronic health problems such as obesity and diabetes.

What is the usual sleep pattern?

At night, when we turn off the lights, the body calms down and falls into sleep. Within a single cycle of sleep, five different periods of sleep, which represent one cycle, rhythmically change within 90-100 minutes. As a rule, three to five cycles are repeated one after the other.

It's typical for healthy adults that they fall asleep at night in ten to fifteen minutes after the light is switched off. First, a quiet sleep period occurs, also known as the non-REM sleep phase. Within this phase, four sleep periods follow: nap, light, deep and deepest sleep.

Usually, 60–90 minutes after the start of sleep, a lively sleep period occurs. The name was given by the characteristic Rapid Eye Movement – REM. A vibrant sleep period periodically recurs throughout the night at about 90 minutes and represents about 20%–25% of all sleep time. It is true that the sleep pattern changes towards the morning. The main actors become the nap, light sleep and the REM phase.

What is the normal rhythm of sleep?

Our body reminds us that we need sleep. The correct timing of sleep and alertness, body temperature fluctuations, enzymatic activity and blood pressure fluctuations are regulated by messages that come from the central circadian pacemaker or the internal clock that works in our body continuously 24 hours a day.

The normal rhythm of sleep is falling asleep in the evening and sleeping after ten to fifteen minutes . The feeling of sleepiness is associated with the elimination of melatonin, a hormone that is excreted primarily at night, while in the morning, in sunlight, its amount begins to decrease.

In the morning, a wake-up system that receives impulses from somatic and sensory systems is activated and their messages are forwarded to the central nervous system.

When we are sleeping, we are not aware of ourselves and our surroundings; however, we can detect strong sensory stimuli from the surrounding area that can awaken us.

How much sleep do we need?

Not everyone has the same need for sleep. As a rule, if we wake up fresh and rested in the morning it is a sign that we have slept enough. In any case, babies and children need more sleep hours than adults and the elderly.

Age group

The amount of sleep within 24 hours


Approximately 16 hours


3–12 months: 14–15 hours
Sleeping children consists of sleeping at night, followed by nap during the day.


1–3 years: 12–14 hours
3–5 years: 11–13 hours
6–12 years: 10–11 hours


Approximately 9 hours
The problem is mainly that the biological clock of adolescents is programmed for staying awake late into the night and late morning awakening.


7 to 8 hours of sleep is the optimal amount of sleep for most adults, although some individuals need only 5 hours and others more than 10 hours of sleep.


According to recent studies, the elderly need at least as much, if not more sleep more than younger adults. Napping throughout the day may help the elderly to get enough sleep.

Pregnant women

During pregnancy, women may need additional hours of sleep.