Sleep disorders

Why we don’t sleep

Bad nights are disruptive to a person’s life. Fortunately, scientists are constantly learning more about the causes.

Amnesty International considers prolonged sleep deprivation a form of torture, underscoring just how important a good night’s sleep is to a healthy life. Even so, up to 10% of the European population suffers from a lack of shuteye. For some the problem is self-inflicted, but for others it is a pathology. The four most common disorders:

1. Bad sleep hygiene

We’ve all experienced lying awake in bed, not able to fall asleep. In most cases, it’s simply a matter of bad habits. “Drinking too much coffee or alcohol in the evening, using your phone, tablet or computer before bedtime, keeping your smartphone by the bed – these are all examples of bad sleep hygiene, which causes people to get too little sleep,” explains Philip Tønnesen, a researcher at the Centre for Sleep Medicine, Rigshospitalet, Denmark. His advice is simple: don’t exercise during the three hours before bedtime, stay off coffee in the evening, and limit your time in front of screens.

2. Narcolepsy

Affecting only one in every 10,000 to 20,000 people, narcolepsy is not as common as it is serious. Best known from funny movies in which people fall asleep into their dinner plate, narcolepsy is caused by a lack of the peptide that keeps us awake. Narcoleptics will fall asleep anywhere and everywhere and might also suffer from sudden collapses due to lack of muscle tension following strong emotions, called cataplexy. “Narcolepsy usually hits young people around 20,” explains

Professor Michael Wiegand of the Schlafzentrum, the sleep medicine centre at the Technical University of Munich. “In addition to medication, they almost always need psychotherapy because the disease has led them to repeated failures in their education, jobs and relationships”.

With proper medication, most narcoleptics become well enough to earn back their driver’s license, and as they grow older the disease usually weakens. Scientists may even be on the way to a cure. “We are really close to finding the real cause, the reason they lack this peptide,” say Wiegand. “We’re not there yet, but we’ll get there.”

3. Insomnia

This is divided between the acute and the chronic form. Insomnia is characterized by difficulty in falling and/or staying asleep, followed by a feeling of tiredness throughout the day. Chronic insomnia lasts for a minimum of three months, but often it can go on for years. Five to 10% of people in Europe suffer from it. “There’s a major psychological component in insomnia, and the acute version is almost always ‘in the head’, for instance due to stress”, says Tønnesen. “Chronic insomnia is often kick-started by a psychological problem, and then it somehow evolves into a vicious cycle of concerns that add stress and make it even harder to sleep”.

A few disorders like schizophrenia can lead to insomnia, but according to Tønnesen it’s rare to find a physiological reason for lack of sleep. Contrary to common beliefs, sleep medication is rarely prescribed anymore. Instead, insomniacs have to work on their sleep hygiene, while two to three months of cognitive therapy has proven the best choice for the really tough cases.

4. Sleep apnea

Characterized by a stop-go breathing pattern through the night, apnea is the most common physiological sleep disorder. A person will stop breathing between five and 100 times per hour for up to 30 seconds because the tongue falls back and blocks the throat – which is why it’s called obstructive sleep apnea. Two percent of women and 5% of men struggle with sleep apnea, meaning they are always tired. For good reason: when we sleep, we use a special function that allows our brain to get some shuteye. But when we stop breathing, the brain is activated, and if you stop breathing every two minutes throughout the night, the brain may not get any rest at all. Sleep apnea can have serious health effects: a higher risk of cardiovascular disease, including strokes, and a higher risk of premature death.

For milder forms, the first treatment is usually lifestyle-related. Three out of four patients are overweight, so losing some kilos can help. For those with moderate to severe sleep apnea, a mask-like device called CPAP (for Continuous Positive Airway Pressure) is the standard treatment. Worn every night, it blows pressurised air into the mouth and nose to keep the throat open. Other options include braces that immobilise the tongue and various forms of surgery. Tønnesen is working on a small device for people whose sleep apnea depends on their sleeping position. Strapped around patients’ chests, it vibrates when they turn on their backs and stops when they return to their sides.

Diagnostic tool

“Sleep is a basic physiological phenomenon with significant implication for health and disease,” says Poul Jennum, head of the Danish Centre of Sleep Medicine. This is the reason he and Helge Bjarup Sørensen of the Department of Electrical Engineering at the Technical University of Denmark are analysing and interpreting data from thousands of sleeping patients for markers of neurodegenerative diseases. “We work together to design automatic methods to search all this data for unusual events that can work as biomarkers for a specific disease. We then implement the discoveries into high-speed algorithms that reduce the time it takes to manually analyse data from a sleeping patient from 3-5 man hours to a few computer minutes,” says Sørensen.

Their cooperation has resulted in software for home detection of sleep patterns as well as a patented discovery of electrophysiological biomarkers that combine data from REM sleep with muscle-activity data. The researchers believe that this could help doctors diagnose Parkinson’s disease 10-12 years earlier than what is possible today. “We are currently designing an algorithm that can analyse the data from a patient and give their doctor a risk profile. This discovery might help patients and doctors as well as society,” says Jennum.

Cultural phenomenon

Even though there is a genetic component to sleep and the minimum amount of sleep we can live with, sleep has changed to reflect societies throughout history. The Schlafzentrum’s Michael Wiegand notes that in the Middle Ages, before electrical light, people would go to bed when it got dark early in the evening, and then around midnight they would get back up and meet in the market place – “for a sleeping break” – before going back to bed around 2 a.m. Nowadays, if you travel in Asia, you often see people sleeping in restaurants or even at scientific lectures. “Sleeping in public is used as a signal to say that you are a very busy man,” says Wiegand.

Philip Tønnesen (Danish Centre of Sleep Medicine), Michael Wiegand (Schlafmedizinisches Zentrum München), Poul Jennum (Danish Centre of Sleep Medicine), Helge Bjarup Sørensen (Technical University of Denmark)