``Sleep is as necessary as eating and drinking``

Interview with Dr. Manuel Eglau

Medical Director of the Centre for Sleep Medicine

Interview with Dr. Manuel Eglau on the importance of sleep for our health

Sleep disorders are a widespread disease. They not only have very direct effects for each individual, but also for the society. The head of the Centre for Sleep Medicine, Dr. Manuel Eglau, provides information about risks, treatment options, and the latest scientific research. He also gives many useful tips for a healthy sleep.


Dr. Eglau, do you have good news for people with sleep disorders?

Eglau: I have very good news for the vast majority of those affected, because the diagnostic possibilities available today allow the sleep specialist to make a precise diagnosis and this is the indispensable prerequisite for successful therapy. If sleep disorders are diagnosed professionally and thoroughly, even chronic sleep disorders that have been present for many years can usually be treated successfully. If left untreated, chronic sleep disorders are associated with a significantly increased risk of a variety of physical and mental illnesses.

Quite wrongly, sleep disorders are usually not taken seriously and dismissed as trivial complaints. However, disturbed sleep can have serious health consequences. Moreover, overtiredness is one of the main causes of serious accidents. Sleep is neither a luxury nor a waste of time, as our society sometimes suggests, but rather the basic prerequisite for well-being, health, and performance.


What new scientific findings can benefit us?

Eglau: Immediately following my answer above, study results indicate a connection between sleep duration and physical and mental health: People who sleep less than seven hours have an increased risk of developing a so-called metabolic syndrome (overweight with abdominal fat storage, high blood pressure, increased blood fat, and blood sugar levels), and cardiovascular diseases and strokes occur significantly more often than in sleep-healthy people. Furthermore, there was an overall increase in mortality for both shortened and prolonged sleep duration. In addition, chronic insomnia and sleep disturbance resulted in a significantly increased risk of mental disorders, such as depression, anxiety, and dependency disorders, and an increased risk of suicide attempts.

The study results on the topic of sleep and memory are also very interesting. According to these, sleep promotes the consolidation and storage of newly learned content, sleep stabilises and improves memory performance. Conversely, untreated sleep disorders lead to a deterioration of memory performance. These findings are of particular importance for the treatment of patients in neurological rehabilitation, because here it is usually a matter of relearning certain skills, such as walking or speaking. Certain sleep disorders have a particularly unfavourable effect on therapeutic progress after stroke. In this respect, the assessment and treatment of sleep disorders is of particular importance for this large group of patients, as it offers the chance of a faster and more extensive recovery.


Are sleep disorders common? How many people are affected?

Eglau: In the general population, 20 % complain of occasional or frequent sleep disorders and 10 % report negative effects during the day, such as impaired concentration and memory, increased tiredness and sleepiness and an overall reduced performance. For Germany, a study put the prevalence of sleep disorders at 7.4 million and the follow-up costs for medical treatment and lost production at 7.3 billion euros per year. Sleep disorders are the third most frequent reason for a visit to the doctor in Germany and it is assumed that about 1.4 to 1.9 million patients are dependent on sleeping pills. Sleep disorders increase the general risk of accidents up to 7-fold, and about one third of fatal traffic accidents are due to drowsiness and micro sleep at the wheel.

These figures speak for themselves, are more than alarming and underline the need to clarify and treat sleep disorders earlier and more thoroughly than has been the case up to now. In addition to the high level of suffering for those affected and the negative effects on health, there are also considerable economic consequences for society.


What is actually behind the phenomenon of sleep?

Eglau: People spend a third of their lives asleep. Sleep is as vital as eating or drinking. In experiments, animals die from prolonged sleep deprivation. Contrary to thousands of years of belief, sleep is not an unconscious or passive state. Rather, sleep is a highly active process with a rhythmically clearly structured alternation of different sleep phases, in which certain brain regions sometimes show higher activity than in the waking state. Today we know about the great importance of sufficiently long and restful sleep for regeneration and learning processes. In studies, sleep deprivation in healthy people led to a clear deterioration in learning and retention performance. In addition, changes in glucose metabolism with the occurrence of increased blood sugar levels and reduced antibody formation after vaccinations were found to indicate a weakening of the immune system.


Is there a typical case in your sleep laboratory?

Eglau: In sleep medicine, we have to deal with a multitude of sometimes very different clinical pictures. Nevertheless, as in every medical field, there are a number of diseases that occur particularly frequently. Simplified, sleep disorders can be divided into four major groups: insomnia (difficulty falling asleep or sleeping through the night), hypersomnia (excessive daytime sleepiness), parasomnia (conspicuous behaviour during sleep, e.g. sleepwalking), and sleep-wake rhythm disorders (e.g. during shift work, jet lag).

For example, restless legs syndrome (RLS) affects an average of 10% of the population, most of whom are women. RLS is one of the most common neurological diseases. It is therefore even more astonishing that RLS, which is associated with insensations of the legs in the evening and at rest and the resulting urge to move, and which can lead to considerable daytime sleepiness due to pronounced problems falling asleep and sleeping through the night, is only diagnosed in most cases after years. This is all the more regrettable because this sleep disorder can be treated excellently.

Another widespread disease, which affects about 4% of men, is “obstructive sleep apnoea syndrome” (OSAS). A recent publication on the prevalence of OSAS in Germany indicated an average prevalence of 30% of men and 13% of women across all age groups in adults; in children, the prevalence is approximately 4%. With increasing age, the frequency of the sleep disorder increases significantly. In case of OSAS, the upper airways become obstructed during sleep due to slackening of the throat muscles and the tongue falling back. The subsequent shortness of breath leads to a waking reaction, whereby the airways are cleared again through an increase in muscle tension. As these waking reactions usually last only a few seconds, the patient cannot remember them himself, but occasionally he reports feelings of suffocation during sleep. These waking reactions can be repeated hundreds of times in one night and thus lead to a significant impairment of sleep continuity, which is why they usually wake up in the morning feeling exhausted and with a headache. Partners often report snoring and irregular breathing, which is why they should be present at the consultation if possible. Recent scientific studies have identified this sleep disorder as a significant and independent risk factor for stroke, heart attack, high blood pressure, cardiac arrhythmias, kidney weakness, and diabetes. OSAS is particularly common in stroke patients, affecting at least 40%. Now the good news: OSAS can be treated very successfully, but not with medication, but for example by adjusting to a so-called positive pressure therapy. Here, a device directs air with a slight overpressure into the airways during the night, which keeps the airways open. Depending on the severity, it can also be treated by using a special lower jaw splint or by avoiding the supine position.

Another form of sleep-related breathing disorder is the “central sleep apnoea syndrome” (CSAS), which causes a malfunction of the respiratory regulation in the brain, leading to a short-lasting failure of respiratory movements. CSAS is often found after a stroke, but also in 30 to 50 percent of patients with heart failure and is associated with a lower quality of life and increased mortality. A special form of ventilation seems to be able to increase the life expectancy of many of these patients by normalising their breathing and improving their heart function.

Insomnia, i.e. unrestful sleep due to problems falling asleep or staying asleep, affects 10-20% of the population. Unrestful sleep leads to severe impairment of social and occupational performance and is associated with feelings of restlessness, irritability, anxiety, depression, exhaustion, and fatigue. The most common is psychophysiological insomnia, which develops as a result of chronically elevated levels of physical, emotional, and mental tension and is associated with sleep-preventing thoughts and misbehaviours related to healthy sleep. However, insomnia is also frequently found as a concomitant complaint in the context of other diseases. In the neurological field, dementia, Parkinson’s disease, multiple sclerosis, craniocerebral injuries, neuromuscular diseases, and strokes should be mentioned in particular. However, mental illnesses, especially depression, and a variety of other physical illnesses as well as medication can also lead to severe insomnia. The therapy of insomnia is always oriented towards the cause and includes both non-drug measures (e.g. training in sleep hygiene, keeping a sleep diary, relaxation methods, and behavioural therapy techniques) and drug measures, which are sometimes used in combination.

The method of stimulus control has proven to be particularly effective. Patients should avoid lying awake in bed as much as possible or leave the bed if they cannot fall asleep within 10 to 15 minutes. They should then go to another room, listen to quiet music, read something relaxing, and only go back to bed when they feel sleepy. Using this trick, this negative conditioning can be dissolved within 2-3 weeks in about 80% of cases. However, this requires a certain amount of perseverance. Certain medications can also be used as a support in cases of high suffering, but these are only administered over a short period of time and in a very low dose. It is also important that they do not lead to dependence.

There is a close relationship between sleep disorders and dementia, as indicated by a number of studies. Sleep deprivation and sleep disorders are often associated with reduced cognitive performance. Sleep disturbances could therefore be an early sign of Alzheimer’s disease, and possibly also a cause of dementia. In a long-term study, participants with sleep disorders who did not yet have cognitive impairment had elevated biomarkers of Alzheimer’s disease (beta-amyloids and tau protein). When one sleeps well, these pathological proteins are passed through the glymphe in the brain into the lymphatic system. Thus, the “pollutants” are flushed out of the brain every night and the brain is “detoxified”.


How does a night in the sleep laboratory look like?

Eglau: An examination in the sleep laboratory (so-called polysomnography) usually extends over 2-3 nights; if daytime sleepiness is present, additional daytime examinations are necessary. The first night’s recording is also called an adaptation night; here, the patient should first get used to the unfamiliar sleeping environment. The second discharge then serves as the actual diagnostic night. However, if the patient has a sleep-related breathing disorder, the second night is used as a therapy night, e.g. to adjust to a positive pressure therapy.

The vast majority of patients feel comfortable in the sleep laboratory and it is not uncommon for patients to report sleeping better than at home! In this respect, nobody needs to be afraid of this examination. Polysomnography is an excellent and very gentle way to shed light on the actual cause of the sleep disorder.


What happens during a sleep laboratory examination?

Eglau: The basis of every successful therapy is first of all the detailed conversation between me and the patient, from which important information is obtained, which then leads to further diagnostics in the sleep laboratory, if necessary. Before a patient presents at the sleep outpatient clinic of our clinic in Allensbach, he or she completes various questionnaires and keeps a sleep diary so that I can get an overview of the type of sleep disorder before the outpatient appointment. Once I have made the diagnosis, individual treatment follows with the aim of reversing the sleep disorder as far as possible or restoring restful sleep. The duration of the treatment varies and depends on the type and severity of the sleep disorder.


What tips do you have for healthy sleep?

Eglau: The following sleep hygiene rules form the basis for successful therapy of most sleep disorders:

  • Keep a regular sleep-wake rhythm with a time of getting up that is as consistent as possible.
  • Only go to bed when you feel sleepy.
  • Make a habit of going to bed, such as reading something relaxing in bed, listening to quiet music, or taking a short walk before going to bed. Every sleep-healthy person has a certain ritual.
  • Do endurance sports (jogging, swimming, cycling) several times a week, but preferably not later in the evening, and do not overexert yourself.
  • If you take a nap, do not take it for more than 10-20 minutes.
  • Air out the bedroom before sleeping, avoid temperatures that are too cold or too warm (approx. 16-18°C); the room should be quiet and darkened.
  • Avoid nicotine if possible, do not consume caffeinated drinks after 4pm, and avoid late, heavy meals.
  • Avoid alcohol, which aggravates sleep disturbances and causes early waking.
  • Create a comfortable atmosphere in the bedroom, PC or TV have no place in the bedroom, and remove all things that have to do with work.
  • Let the day end calmly, pending problems should be solved during the day if possible.
  • Relaxation techniques can help you to find inner serenity; this is the key to sleep.