How many hours of sleep do we actually need? And why it is so healthy? What the terms "owl" or "lark" are all about and which stages we go through during the night, we have summarized for you in the following, together with our experts.
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We reveal the most important background information on the subject of healthy sleep
At night, we lie motionless in bed for hours and nothing happens – one might think. "Far from it," says Andreas Eger. "Sleep is vital for us, and our bodies are highly active during it."
Why we sleep at all has not been precisely clarified to this day. What is known, however, is that healthy sleep is essential for life. It is not simply the opposite of active wakefulness. Certain bodily functions are even very active.
- The metabolic system: Particularly in the first hours of sleep, our body produces Hormones, which are important for growth, wound healing and cell regeneration. At the same time, the level of Stress hormone cortisol.
- The immune system: while in dreamland, our immune system releases more defense cells. The increased Need for sleep during infections Is thus a sensible reaction of our body.
- Memory: During REM sleep in particular (see illustration of sleep stages), important information is stored, while unimportant information is sorted out. Is the REM sleep phase disturbed, memory contents are stored worse. So if you have drunk a lot in the evening Alcohol drink a lot in the evening, remembers less later.
- Detoxification: During sleep, the intercellular spaces in the brain widen, allowing the neural fluid to flow more easily and remove harmful substances.
Sleep patterns: How much (healthy) sleep do we need?
Being awake during the day, sleeping at night – many take this for granted. However, we are not born with this behavior: newborns sleep several times throughout the day and only gradually adjust their sleep-wake rhythm as they grow older.
"It is therefore assumed that the sleep rhythm has adapted evolutionarily to the times of day," says Eger. "So as (mostly) diurnal creatures, we get tired at the right time now."
As "normal" a sleep need of about six to eight hours per night considered, according to Eger. Almost three out of four people fell into this category. It is irrelevant when the sleep takes place. Bedtime plays no role in restfulness. Nor whether sleep is caught up at night "in one go" or spread out over the day, for example with a midday nap.
According to Eger, sleep medicine focuses on two main factors Sleep types differentiated:
Long sleepers vs. Short sleeper:
Anyone who needs more than eight or less than six hours of sleep is considered a deviant from normal sleep patterns.
Long sleepers do not automatically sleep better than short sleepers. Detoxify the body, strengthen the immune system: The proportion of deep sleep is particularly important for healthy sleep, that promotes growth, immunization and detoxification. People who get by on comparatively little sleep usually get just as much deep sleep during the night as late sleepers, which in turn strengthens their health.
Larks versus owls:
To distinguish between early risers and late risers, terms have been borrowed from the bird world: typical Larks (early risers) get up early – like the corresponding bird – and are immediately lively, efficient and in a good mood. They also go to bed early in the evening.
The Owls (morning grouch) On the other hand, older people have trouble getting out of bed in the morning and take a long time to become fit. They really blossom in the evening and can work – or party – with concentration until the wee hours of the morning.
In addition, Eger says that other types can be distinguished, for example sensitive sleepers and very deep sleepers. Infants and toddlers, for example, may sleep so deeply that disco music can be played at the same time. For others, the ticking of an alarm clock is enough to disturb their sleep.
Age- and gender-specific factors play a major role in sleep behavior: Older people become more sensitive and more prone to sleep disorders. Infants and toddlers need more sleep than adults for this purpose.
"In old age, it then turns around again," says Eger: "Contrary to popular belief, older people need more sleep again." However, this is often accompanied by a change in sleep behavior: Retired people take a nap more often, so that the amount of sleep increases overall – but is distributed differently over day and night.
"In addition, sleep becomes more superficial," says Eger. "The proportion of deep sleep phases and REM sleep decreases with age."