Healthy sleep: how it works
Those who want to optimise their health cannot ignore sleep. What constitutes good sleep and how to achieve it.
We spend a third of our lives asleep, and yet the functions of sleep are still relatively unknown. What research does know, however: while we sleep, the body is working for our health. It regenerates cells, strengthens our immune system, regulates our hormone balance and processes the information of the day.
Our brains declutter when we sleep
While we sleep, our brain remains active. On the one hand, the brain works on our neuroplasticity. This involves the adaptability and changeability of our synapses, nerve cells or entire areas of the brain. Neuroplasticity is the basis for all learning. Every day, countless nerve cells connect. At night, the brain cleans out the connections that we no longer need in order to create new capacity in our control centre. This means that the synapses we need are retained and strengthened, important things are anchored in our memory and unimportant things are discarded. This decluttering process takes place in particular during deep sleep. On the other hand, the brain also removes harmful metabolic products during sleep. These occur during the day when the brain is active. When our sleep is disturbed, this important cleansing process is hindered.
Sleep influences practically all processes in the body
While we sleep - but especially during deep sleep - the body regulates countless processes that are central to our health. First and foremost, our body’s cells regenerate. Our hormonal balance also regulates itself. This has a direct influence on our metabolism – i.e. how we metabolise food, how we feel and how well our immune system is able to defend itself. For example, insufficient sleep can lead to obesity, mood swings or immune deficiency. Sleep also strengthens our cognitive abilities, memory and ability to concentrate.
Sleep is important for our mental well-being
Sleep and mental health are closely intertwined. Let’s take a closer look at the interplay between the two: A few bad nights or phases of poor sleep are completely normal in our lives. But if these phases continue, they can have consequences for our mental health. So it’s important that those affected seek help at an early stage – because sleep problems can become chronic relatively quickly and are then all the more difficult to get rid of. Sleep experts speak of a chronic sleep disorder or insomnia if a person has difficulty falling asleep, sleeping through the night or doesn’t sleep enough at least three times a week over a period of one month.
Insomnia is the most common sleep disorder. Sleep apnoea is also very common. In this case, those affected stop breathing repeatedly during sleep, which greatly disturbs their sleep. Many sufferers are not aware of this, says sleep expert Björn Rasch. This makes it all the more important to consult a doctor if you have been sleeping badly for several weeks. Unlike insomnia, sleep apnoea can be remedied quite easily with a breathing aid.
Both insomnia and sleep apnoea make those affected more prone to risk-taking, irritability and lack of concentration. What’s more, they can trigger anxiety disorders, depression or addictions and impair memory. This is illustrated by the fact that mentally healthy people with severe chronic sleep disorders run around twice the risk of developing depression five to ten years later. Even people with sleep disorders who have recovered from depression run a higher risk of falling ill again.
“Our sleep is like a barometer that reveals our mental health.”
If you can’t sleep, you should consider your mental well-being
And our sleep suffers if we feel imbalanced and stressed or facing a crisis. “Our sleep is like a barometer that reveals our mental health,” says Rasch. We’re aware of this in acute crises – but less so in everyday stressful situations. We should therefore ask ourselves what stresses us out during the day; for example, where the pressure of expectations on ourselves is too high or professional and social obligations are too much. “That’s where we can start to feel better – and therefore sleep better again,” says Rasch.
The fact that the mind is our most powerful tool for getting good sleep is also proven by the success of psychotherapy for people with chronic sleep disorders. “Psychotherapy has now become the standard treatment for insomnia – and it has a positive, lasting effect,” says Rasch.
Sleep quality is always subjective
Quality of sleep is difficult to measure physically – it usually lies more in the subjective perception of the individual person. Similarly, insomnia cannot be measured or diagnosed physically, as it is often not based on an organic problem in the body.
Sleep patterns, sleep phases etc. – you should be familiar with these myths about sleep
Only those who don’t wake up at night have a healthy sleep. Counting sheep helps you fall asleep. Or eight hours of sleep is perfect. There are many myths surrounding our sleep. We’ve taken a closer look at six of them:
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Sleep deficiency: if you don’t sleep well, you should go to bed earlier
This much-heard advice is counterproductive, says Björn Rasch, sleep researcher and professor of psychology at the University of Freiburg. You should do the opposite and only go to bed when you’re tired. The more you need to sleep, the faster you’ll nod off. The aim is to sleep shorter but more efficiently.
If you go to bed earlier when you’re having problems sleeping, you’ll only make it worse. You hope it’ll help you relax, but you’ll probably end up spending more time awake in bed tossing and turning, which in turn makes it more difficult to fall asleep and increases frustration about your lack of sleep.
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Sleep phases: sleep before midnight is the most beneficial
This claim may apply to early birds who hit the hay early in the evening so they can get up first thing the next morning. Generally speaking, however, it’s not true, says sleep expert Rasch. So, night people – known as “owls” by sleep researchers – who rarely get to sleep before midnight don’t need to worry about their health or productivity.
This is because numerous studies show that the first three to four hours of our sleep contain particularly many moments of deep sleep and are therefore very restorative – regardless of when we fall asleep. The sleep phases are therefore always the same if we regularly go to bed at similar times.
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Optimal sleep duration I: We need at least eight hours of sleep
The need for sleep varies from person to person, says Rasch. The oft-mentioned eight hours rule is therefore nonsensical. Instead, a healthy person may need anything between six and ten hours of sleep. These figures do not refer to one-off nights, but to a general need for sleep.
Pay attention to when you feel rested in the morning. Perhaps in your case this may be after just six hours – while others need nine hours. Listen to your body.
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Optimal sleep duration II: Too little sleep has a negative impact on our lifespan
This statement isn’t true, says expert Rasch. “Studies show no significant increase in mortality risk with a regular sleep duration of four to six hours.”
There is one exception: Those who consistently sleep too much – around ten hours or more every night (for adults) – may have a higher mortality risk. However, probably not because of the sleep itself, but because this high need for sleep is often an indication of a secondary illness. This causes those affected to sleep so much.
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The sleep hormone melatonin: Mobile phone use before bedtime makes it difficult to fall asleep
Yes and no. If you stay on your mobile phone until you go to bed or even let yourself be woken up to be constantly reachable, you are disturbing your sleep. So it’s better not to take your mobile phone into the bedroom.
However, the latest studies have shown that the so-called blue light from electronic devices has less of an effect on the body than previously assumed – in particular not on the production of the sleep hormone melatonin.
One study examined the sleep quality of test subjects who had watched Netflix for three hours before falling asleep. “Although they tended to go to bed later and thus shortened their opportunity to sleep, the majority of them were still able to sleep well,” says Rasch.
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Disruptive factors: the full moon makes sleep more difficult
The belief that the moon and especially the full moon influence sleep is widespread and has become even more widespread in recent years. However, the scientific evidence for this effect is limited and also inconclusive. For example, the light of the full moon could have an influence on sleep, especially in rural regions without much artificial light. However, this effect can be eliminated quite easily by darkening the bedroom.
However, the gravitational pull of the moon can probably be ruled out as the cause: as we know from the ebb and flow of the tides, the moon’s gravitational pull fluctuates greatly throughout the day, whereas the gravitational pull only changes slightly between the new moon and the full moon. However, there are barely any reports of a connection between sleep quality and the tides, says sleep researcher Rasch.
Tips for sleep hygiene: Take care of your sleep like your body!
Take care of the quality of your sleep – so that you feel more rested in the morning and avoid any consequences, including illnesses, that may be caused or exacerbated by inadequate sleep.
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Stay calm
Stay calm, even if it’s difficult to sleep. It is quite natural that the quality of your sleep is not always the same. Don’t get too uptight about falling asleep again as quickly as possible in such situations or trying to get rid of your sleep problems as quickly as possible. Listen to your body: How do you feel? Are you stressed? Do you feel under pressure? That’s where to start during the day.
In addition, quality of sleep generally decreases with increasing age. Sleep experts advise not to force yourself to go back to sleep at 3 a.m. If you can, continue to lie down and do relaxation or breathing exercises or meditate. Or get up and do something. If your everyday life allows it – those affected are often no longer involved in working life – go back to bed when you are most likely to get tired again, at around 5 or 6 in the morning.
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The right sleep rhythm: less becomes more
Shorten your time in bed if you’re sleeping badly. If you are spending too long in bed, you will end up dozing and not building up enough sleep pressure for actual deep sleep. A sleep diary can help you get an overview of your own sleep cycle and how well you sleep in which situations.
For example, how long and how well do you sleep on holiday when you have fewer social and work commitments? According to experts, this is often a good indicator of your own sleep needs and sleep pattern.
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Optimal sleep duration: Adapt your sleep window and go to sleep at regular times
The next important tip for healthy sleep: Adjust your rest time according to your own chronotype. This means you should find out when you are most inclined to sleep. “Early birds and night owls really do exist. So perhaps I sleep best from 10 p.m. to 4 a.m. or from 1 a.m. to 7 a.m.
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Create more relaxation during the day to sleep better at night
Consider the situation carefully during the day: How should I organise my day? Why do I feel overburdened? What expectations do I have of myself? Are they perhaps too high? How can I organise my everyday life better? When can I take breaks to switch off? How can I practise mindfulness? When can I find time for physical exercise? And how can I integrate activities into my life that make me happy?
