Dossier: Strong mind

Sleep hygiene: vital for our well-being

We know how much we suffer when we haven’t slept enough. And we don’t sleep well in stressful situations either. Psychiatrist and sleep researcher Christoph Nissen explains the effect of sleep on our well-being and what we can do to sleep better.

Text: Katharina Rilling; Photo: Annie Sprat / Unsplash

Poor sleep results in a bad mood, not being able to concentrate and makes you less resilient. You are more likely to find yourself in a conflict and more prone to mistakes, your mood darkens and the day stretches out in front of you like a great yawning void. It becomes very quickly apparent: we cannot function on too little sleep. And vice versa, our sleep suffers if we feel imbalanced and stressed or facing a crisis.

And the science confirms what we know in everyday life: “Sleep and mental health are closely connected” says sleep researcher and psychiatrist Christoph Nissen, chief consultant and deputy director at the University Psychiatric Services, Bern. “We have known for a long time that many psychiatric problems such as panic attacks and depression lead to sleep disorders. More recent research has indicated that this is also the case vice versa: healthy sleep is vital for our mental health”. But how exactly does lack of sleep affect us? How can I promote healthy sleep? What might help me fall asleep? And from what point on do sleepless nights start to affect us? 

Fact 1: sleep disorders can have a huge impact on our mental well-being and vice versa.

“The odd sleepless night or period of poor sleep is part and parcel of life. It does not necessarily indicate a problem of a medical nature. It won’t help to drive yourself crazy with worry,” says the chief consultant. “Persistent and severe sleep disorders are however a large risk factor for psychiatric problems.” Someone who has three sleepless nights a week over a period of three months or more, or who can’t sleep without constantly waking up or doesn’t get enough sleep is probably suffering from the most common sleep disorder: insomnia.

Sleep disorders such as insomnia and sleep apnoea make people less risk averse, more irritable and unable to concentrate. In addition it may cause panic attacks, depression or lead to addiction and memory loss. “Psychologically healthy people who suffer from a severe and chronic sleep disorder are around twice as likely to suffer from depression five to ten years down the line.” Patients with a sleep disorder who previously suffered from depression are also more likely to suffer from it again. Clearly sleep disorders are more than a mere inconvenience and often symptomatic of a psychiatric problem as we have long suspected. They can also be triggers for such diseases. 

This is valuable knowledge for diagnostics and therapy in order to recognise, treat and prevent psychiatric diseases at an early stage. “In recent years we have discovered that sleep is an important parameter for health that requires special treatment”, says Nissen. And initial research has shown that, in addition to the more traditional treatment methods, a psychiatric disease prognosis can be improved upon through sleep training. 

The odd sleepless night or period of poor sleep is part and parcel of life. Persistent sleep disorders are however a large risk factor for psychiatric problems.

Fact 2: we declutter our brains when we sleep 

So why does sleep help keep us healthy? “The role that sleep plays for our health still remains surprisingly unknown even though we spend around a third of our lives asleep. Something that occupies so much of our time must be a vital function of our bodies”, says Nissen. “Otherwise evolution would have made a big mistake.”

There are two hypotheses: One is that sleep is important for the so-called neuronal plasticity, in other words the ability of synapses, nerve cells and whole areas of the brain to adapt and change. This is the basis for all learning. Every day lots of nerve cells make new connections and the brain needs to declutter in order to create more capacity. This means relevant synapses are preserved and strengthened and important things are deeply rooted in the memory and trivial stuff is forgotten. This decluttering tends to happen during periods of deep sleep. 

The second hypothesis is that harmful metabolic products that accumulate in the brain during the day are removed. This cleaning happens predominantly during sleep. If it is disturbed, essential processes in the brain are hampered. 

It is interesting to note that this process is slightly different for people suffering from depression. “A healthy person feels shattered after a poor night’s sleep. Someone suffering from depression will experience the exact opposite: A sleepless night can have a powerful effect on the following day and help alleviate the symptoms”, says the chief consultant. The problem with prescribing sleep deprivation as a form of therapy is that patients often fall back into depressive moods once they have caught up on their sleep. Sleep practically makes them ill again. “Highly interesting from a scientific standpoint is that it is possible to dramatically improve the state of depression within hours. The ability of nerve cells to connect together appears to be diminished in someone suffering from depression and presumably momentarily normalised through sleep deprivation.” 

Fact 3: all sleep is not good sleep

Some say you can sleep when you’re dead, and others would love nothing more than to spend the whole of Sunday in bed. So just how much sleep do we need? And Is it possible to sleep too much? “Sleep differs from person to person”, says Nissen. “and sleep requirements are very much individual”. The sacred eight hours that you tend to read everywhere is complete nonsense. A healthy person may need anything between five and ten hours of sleep. “Someone who only needs five hours of sleep probably lies awake in bed for three hours fretting that they haven’t had eight hours sleep and probably developing a sleep disorder because of it.” And those who toss and turn in bed, doze or whose sleep is often disturbed, do not build up enough sleep pressure for the night.

Which is why some people monitor their sleep with smart watches in order to build a clearer picture of how they sleep. Can this be useful? “It is relatively easy to monitor the activity rhythm between movement and rest. Although it doesn’t really help if you still wake up feeling tired in the morning. These watches do not give you the full picture.” The devices may indicate periods of sleep but not if certain areas in the brain are overactive. “We have recently discovered that individual areas of the brain remain active even if you are in a deep sleep. Your own impression of how you slept doesn’t necessarily need to correspond with what your watch indicates.” Imaging techniques in sleep research offer a clearer picture.