Sleep disorders (insomnia) are expressed either by the feeling that it is difficult to fall asleep or stay asleep through the night, or by the feeling of being increasingly tired during the day, although both sets of complaints can of course occur simultaneously. Short-term sleep disturbances for a few days occur in almost all people in certain stressful situations or during physical illnesses and are harmless. However, sleep disorders that last longer than 3 to 4 weeks require a detailed clarification of the causes, which can be in the area of mental as well as physical health. Sleep disorders are among the most common health problems of all and affect at least 10% of the population.
Humans sleep 7 to 8 hours per night, although the need for sleep can vary greatly from person to person, so that some people can easily get by on 6 hours of sleep throughout their adult lives, while others need up to 9, even 10 hours of sleep. With increasing age, the total amount of sleep over the entire day decreases somewhat, but not significantly. Older people, on the one hand, wake up more frequently during the night and, on the other hand, take more frequent "naps" during the day.

Sufficient and high-quality sleep contributes significantly to health; sleep disorders impair mental stability and can even lead to psychiatric diseases such as depression. In addition, sleep disorders can also affect physical health, they weaken the immune system and are among the possible causes of diabetes.

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