Barbara Hortian, MD: Yes. In recent years, sleep researchers have demonstrated in numerous studies that the brain, psyche and the entire organism regenerate during sleep. During sleep, the body and brain by no means shut down completely, but rather a highly complex process takes place. During the night, humans go through four to five such sleep cycles, each lasting about 90 minutes. The first light sleep is followed by a deep sleep phase. This is followed by another light sleep phase with dream experiences, which we call REM sleep. It is primarily during deep sleep and REM sleep that physical, mental and psychological regeneration takes place.
What happens during the different sleep phases?
Dr. med. Barbara Hortian: During deep sleep, the organism reduces its need for sleep and releases a large number of hormones (especially known: the growth hormone), which are essential for cell repair and the immune system. In the process, the entire organism regenerates. The REM sleep phase organizes and processes information absorbed the day before and the body's own emotions, so that the unimportant is forgotten and the essential is stored in memory. REM sleep is therefore of great importance for mental stability.
Why do we get tired?
Barbara Hortian, MD: Like many other processes that take place in the body, this rhythm is also controlled by certain hormones. In the evening and at night, our body produces the "sleep hormone" melatonin in the pineal gland (epiphysis) of the brain - but only in the dark. Thanks to this hormone, we tire out and sink into a relaxed sleep. In addition, the release of melatonin lowers body temperature, pulse rate and breathing frequency. Our "inner clock" is also closely related to this: Where the optic nerves cross behind the forehead is the so-called nucleus suprachiasmaticus, a nerve node that controls the natural sleep-wake rhythm according to the incidence of light. If the retina registers that it is getting light again, melatonin production stops and we wake up.
So it is up to each individual to get a good night's sleep?
Barbara Hortian, MD: Of course there are sleep disorders with deeper causes. But basically, healthy sleep requires self-discipline. For example, do you really have to sit in front of the computer until late at night? Do you need to be constantly available in the bedroom via smartphone or with the TV on? Anyone who struggles with sleep problems or doesn't get out of bed in the morning feeling refreshed should ask themselves questions like these. Sleep is not a necessary evil, but contributes decisively to inner balance and health.
How much sleep does a person need?
Dr. med. Barbara Hortian: The unconditional fixation on a daily minimum sleep time and a quasi "forcing" of sleep is often very counterproductive. Not everyone necessarily needs six to eight hours of sleep; there is a great deal of variability. In old age, for example, you don't necessarily need less sleep, but your sleep breaks down into several episodes - just like in a toddler. So I wouldn't necessarily want to talk older people out of taking a nap. However, they should not expect to be able to sleep from 10 p.m. to 6 a.m. at night. It would be beneficial to go to bed later or not to be disappointed to wake up "with the chickens". And surely everyone remembers what it was like to be young and in love: Didn't you sometimes have a very short sleep time and still - so full of positive feelings - managed your daily workload well?
Sleep as an important contribution to health ...?
Barbara Hortian, MD: We know that there is a connection between poor sleep and various diseases. It has been proven that there is a close correlation between sleep disorders and depression as a late consequence. Conversely, a sleep disorder can also be the first symptom of an incipient depression. The hormonal processes during sleep, which were only hinted at in the beginning, are actually much more complex. If there are deficits or disturbances here, this can promote the development of obesity, type 2 diabetes and cardiovascular diseases. Last but not least, too little or too restless sleep weakens the immune system, which in turn can result in a higher susceptibility to infections. If we consider the important influence of sleep on the psyche, it is also obvious that a person who is permanently unslept is not really fit and capable of making decisions - this is certainly not doing oneself any favors in everyday and professional life.
Where to go with sleep problems?
Dr. med. Barbara Hortian: First, of course, to the family doctor, where previous illnesses and lifestyle are known. If psychological stress, illnesses or medication can be ruled out as the cause of the sleep problems and no explanations can be found even with further diagnostics, there will be a referral to a specialist. Before that, however, a consultation on sleep hygiene should have taken place: Is my sleeping place quiet, cool enough, darkened and has a comfortable mattress? Do I not eat heavy meals in the evening? Do I end the day quietly and gradually? Do I regularly observe certain sleep rituals? Also, avoid great physical exertion or emotionally stressful situations immediately before bedtime. By the way, listening to audiobooks is an effective tool for banishing bad thoughts during long periods of wakefulness at night.