Albrecht Vorster: "We must not expect too much from sleep"
23.10.2026
Translation: machine translated
How much sleep is necessary? What can I do to sleep better through the night? Our sleep occupies us – perhaps too much, sleep researcher Albrecht Vorster points out. He explains what we should do during the day instead to be able to sleep well at night.
«I'm tired, I'm going to bed.» Most people probably wouldn't find anything to object to in that statement, but Albrecht Vorster would. The sleep researcher explains that tiredness and sleepiness are not the same thing and why that makes a difference. He also clears up other misconceptions: for example, how long we sleep is secondary. So before you read this interview: forget everything you think you know about sleep!
What do most people do wrong when it comes to sleep?
Albrecht Vorster: Nothing, to begin with. About 70 percent of the population does not sleep poorly.
And the other 30 percent?
They suffer from a sleep disorder. 10 to 20 percent of the population have breathing pauses during sleep, known as sleep apnea. 10 percent suffer from an insomnia disorder that requires treatment. About 7 percent suffer from restless legs syndrome, where discomfort in the legs and an urge to move can make falling asleep difficult. In addition, there are less common problems such as nightmare disorders, parasomnias like sleepwalking, and sleep-wake rhythm disorders. In total, we know of more than 20 different sleep disorders.
Source: Albrecht Vorster
That sounds drastic. Are we underestimating the importance of sleep?
Yes and no. Socially, we tend to underestimate sleep, while at the same time we can also overvalue it individually. Let me explain: We underestimate sleep when we view it as passive time that can simply be cut short in favor of work or leisure. Yet important cleanup, restructuring, and processing processes take place in the brain while we sleep. For example, metabolic products are removed, neuronal connections are adjusted, and memory contents are processed. On the other hand, one can also become too preoccupied with sleep: anyone who constantly checks whether they are sleeping enough and well enough creates additional pressure.
How so?
One of the most common mistakes is that we have too precise ideas of what good sleep should look like. The fact that we can meticulously track our sleep today reinforces this phenomenon, even though many people don't even know what to do with the data collected. For example, those famous eight hours that «one» should sleep. That's not true. The need for sleep is individual – after all, we don't all wear the same clothing size. For the vast majority, it lies somewhere between six and nine hours. Thus, the thought of having to sleep eight hours leads to more problems than it solves.
Are sleep recommendations therefore problematic?
Potentially, yes. They can lead to people constantly observing and evaluating their sleep. And in doing so, they increase the pressure of expectation and performance on sleep. It becomes particularly problematic for people who already sleep poorly. Then thoughts arise like: I have to sleep now. I need my eight hours. If I don't sleep today, I won't be productive tomorrow. And that is counterproductive. Exactly such generalizations are consciously addressed in cognitive behavioral therapy for insomnia. With sleep problems, it is therefore partly about changing one's own behavior and expectations of sleep, instead of adding even more sleep rules.
So you don't give a recommendation on how long one should sleep?
Correct. The decisive factor is not to reach a certain number, but to sleep long enough to feel rested. This is best found out during a time without an alarm clock and fixed morning obligations, for example, on vacation. First, sleep in and then note how much you actually sleep in total during the second week. As a rule of thumb, you can say: those who sleep enough do not need to regularly catch up on sleep on the weekend.
And if we occasionally fall short of our sleep expectations?
Stay calm, one bad night is not a drama. And a party can certainly disrupt the rhythm or generate a sleep deficit; our organism can handle that well – and recovers again. In the lab, we see that people can function surprisingly well the following day even after a single very short night. It only becomes more problematic when unfavorable expectations and behaviors solidify and long-term sleep problems arise from them.
Who is the greatest enemy of sleep?
The modern lifestyle.
You mean because we are still glued to our smartphones late into the evening?
That is negligible. But it is actually about light, about daylight: we spend too much time indoors and get relatively little natural light during the day. Outside, several thousand lux fall into our eyes; in artificial light in the office, rarely over 250 lux. If we only see artificial light all day, our body lacks the contrast to the night. That is why I recommend going outside, especially in the morning and around noon.
So we can already promote good sleep during the day?
Of course. With light and movement. But for decades, the employer, especially with shift workers – and not the individual biorhythm – has determined when we get up. So we haven't been moving against nature only since the invention of the smartphone. Social times and biological times are drifting further and further apart, and our everyday life is in many respects decoupled from our internal clock.
Source: Shutterstock / yourphotopie
So it would be good for sleep if we went back to our roots?
We don't have to go back to the Middle Ages, but about 150 years ago, healthier conditions prevailed in terms of sleep because people still lived more according to their own internal clock.
Speaking of the Middle Ages: I recently heard that people used to sleep in two phases. They would wake up in the middle of the night, do something, for example rest awake in an armchair, and then go back to sleep.
You mean the theory of segmented or biphasic sleep. The historian Roger Ekirch cites many individual examples from historical sources for this. If you ask me, that is perhaps the biggest hoax there has been on the subject of sleep. In any case, there is no scientific, especially sleep-scientific, evidence that people used to sleep in two «shifts».
Too bad, I already thought I should try that out. Because I often don't feel rested. No matter how long I sleep...
We shouldn't demand too much from sleep. For example, that it erases our tiredness.
Excuse me?
We must distinguish between tiredness and sleepiness. Medically, these are two different symptoms. Tiredness means that I feel exhausted, lacking energy, or unmotivated. That doesn't necessarily mean that I could fall asleep. Behind this can be, for example, physical or psychological burdens. Sleepiness, on the other hand, is an actual tendency to fall asleep: my eyes are closing, I could doze off during a meeting, while reading, or – especially dangerous – while driving. In short, tiredness stands for «I have no energy» and sleepiness for «I could fall asleep».
Okay. And sleep only combats sleepiness?
It is like this: those who are sleepy may actually need sleep or should have it investigated why the sleep is not restful. Often, sleep apnea is the trigger. Breathing pauses can repeatedly interrupt sleep, which can lead to severe daytime sleepiness and health problems. Those who are constantly tired, on the other hand, even though they sleep enough, should not automatically try to sleep even more. It is worth looking for other causes then.
Can you sleep too much?
I would differentiate between sleeping a lot and lying in bed for a long time. You can, of course, stay in bed for too long. That can lead to feeling even more sluggish. That is why I wouldn't try to «collect» as much sleep as possible, but rather go to bed when I am really sleepy – even if that is later than reasonable – and get up at a fixed time in the morning after at most eight hours in bed.
And if I really sleep for a long time?
If an otherwise healthy person occasionally sleeps longer, that is initially no cause for concern. However, if someone sleeps ten to twelve hours daily, I would have that clarified in a sleep lab.
So sleep duration is less important than one might think: we often have the feeling of missing out on an enormous amount of recovery if we go to bed later.
Exactly. The body regulates that very well and gets the deep sleep it needs – whether in six or nine hours. Besides duration, there are seven other factors: continuity, regularity, subjective satisfaction, alertness during the day, undisturbed breathing, no other sleep disorders, timing. Good sleep is therefore multidimensional. And regularity, for example, is much more important than duration.
Source: Shutterstock / DimaBerlin
You have to explain that.
If we go to bed and get up at roughly the same time every day – plus/minus 30 minutes – we give sleep a stable rhythm. That is why it is also recommended to keep similar bedtimes and wake-up times on the weekend as during the week. Anyone who gets up very early during the week and completely shifts the rhythm on the weekend is not necessarily doing their internal clock a favor. The simplest thing to promote good sleep is therefore to go to bed at the same time as much as possible and to get up at the same time.
To what extent is timing relevant?
There is the widespread assumption that sleep before midnight is totally important. That is correct in that a particularly large amount of deep sleep takes place in the first hours after falling asleep. However, the decisive factor is not whether it is currently midnight on the clock, but when our innate sleep window begins. The fact is: not every person has biologically the same time window for good sleep. We speak of different chronotypes – simplified as larks, normal types, and owls.
Larks are early risers and owls are night owls?
Roughly speaking, yes. With larks, the internal clock runs earlier: they wake up on their own in the morning and are productive, but are tired earlier in the evening. With owls, it is the other way around. They get tired later, are often still productive in the evening, and have greater difficulties getting going in the morning.
Then I am more of an owl, even though I am not a night person.
If you can watch a movie in the evening without any problems without falling asleep in front of the screen, I would say: everything is fine. Either you are fresh in the morning or in the evening. If you expect both, that is actually asking too much of sleep. It becomes problematic when a pronounced evening type has to be at work very early every morning, because then they are permanently living against their internal clock.
And continuity? How important is it to sleep through the night?
First of all: sleeping through the night does not mean being out continuously from falling asleep until morning. If that were the case, no person in the world would have ever slept through the night. Rather, we wake up briefly again and again in the course of a normal night, about 20 times, without noticing it or without remembering it. Nevertheless, we have the feeling: I slept through the night. That has to do with our sleep architecture. We sleep in several cycles and go through different sleep stages in the process. Especially at transitions, short moments of wakefulness can occur. Waking up itself is therefore initially nothing unusual. It can become problematic if you stay awake longer, wake up consciously very often, or do not feel permanently rested the next morning. The decisive question is therefore not: «How often did I wake up at night?», but: «Is my sleep restful overall?»
Waking up about 20 times is normal?
Yes. Only when such arousal reactions occur more frequently and fragment sleep does it become a burden. There is actually no sleep-maintenance disorder, only a sleep-reinitiation disorder. The question is how we deal with waking phases. Get upset, or be happy that we are allowed to relax for a few more hours.
What can we read from sleep?
Our sleep can reveal something about our state of mind and health. But it is not a clear diagnostic instrument. Stress is a good example. When we are stressed, the body puts itself in a state of alert, so to speak: be especially vigilant now! Sleep then becomes lighter, we wake up more often, and start to ruminate more easily. However, anyone who wants to sleep must be able to let go. But the reverse direction is also interesting. Sleep problems can precede mental illnesses. If sleep changes, it can be worth asking: what has just changed in my life? Am I more stressed, worried, or exhausted? But one should not immediately conclude a mental illness from a few bad nights. Sleep problems are also part of normal life at times.
How important is a sleep routine?
Doing the same things over and over again about half an hour before going to bed brings us down and signals to the body: now the night begins. That can be reading, a crossword puzzle, or simply a fixed ritual of airing out, brushing teeth, and dimming the lights. Which routine doesn't matter, the main thing is that you have one.
I always have a lot on when sleeping – is that okay? Especially since it is always said that it should be cool in the bedroom.
Our body uses the evening temperature drop as a signal for the night. That is why a rather cool sleeping environment can support falling asleep. At the same time, the bedroom does not, of course, have to be as cold as possible – anyone who is freezing does not sleep better because of it. It is primarily about maintaining a comfortable body temperature. Whether someone sleeps in pajamas, a T-shirt, or unclothed says little in itself about good sleep.
Which products can help with sleeping?
If the alarm clock pulls you out of sleep unfavorably, getting up can feel extremely unpleasant. Here, for example, a light alarm clock could help, which wakes you up gently. For apnea snorers, there are supine position prevention vests that keep you from sleeping on your back: in the side position, there are fewer breathing pauses due to narrowed airways.
Too tired to sleep – does that exist?
Yes and no. You are then not awake because the body has too much sleep pressure, so to speak. Rather, tiredness and a state of increased alertness can occur at the same time. For example, with insomnia: those affected can be completely exhausted during the day and yet suddenly wide awake in bed. The body has then learned to associate the bed and the upcoming night with tension. Thus, a vicious circle can arise: you are exhausted, therefore want to sleep at all costs, observe your own sleep more and more closely – and thereby build up additional pressure. That is why it is, for example, not necessarily helpful to go to bed particularly early out of exhaustion. Because the longer we lie in bed sleepless, the more strongly our body associates the bed with being awake.
Why are there so many myths and ignorance surrounding sleep?
Modern sleep medicine is a comparatively young discipline. At the same time, it is extremely interdisciplinary and cannot be assigned to a single medical specialty. If, for example, you sleep poorly, the cause can be neurological, pneumological – think of sleep apnea – psychiatric, or endocrinological. In addition, there are chronobiology, internal medicine, and many other areas. The fact that the German Society therefore explicitly speaks of «sleep research and sleep medicine» shows this connection between basic research and clinical work quite well. I myself, for example, originally come from biology and earned my doctorate on memory consolidation during sleep.
Finally: what should everyone know about sleep?
Sleep is important for our physical and mental health – it is one of the four great pillars of our health, alongside nutrition, exercise, and social life. But sleeping poorly occasionally is completely normal. Perhaps that is the most important message: take sleep seriously, without developing a fear of poor sleep.
Audiobooks
Why we sleep - Why our legs sometimes do not find sleep, even snails are clever
Albrecht Vorster, German
Header image: Shutterstock - Prostock-studio
I'm a freelance journalist, communications manager and versatile writer. I prefer to write about topics that fall somewhere between drivel and social relevance.
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