Sleep as a biological rhythm: clinical aspects

Abstract

Insomnia is a widespread disorder affecting not only sleep quantity and quality, but also daytime well-being and performance, as well as having a negative impact on physical and mental health. Many people have problems falling asleep and maintaining sleep that do not reach the clinical criteria of insomnia. For all the prevalence of such sleep disorders, specialists often overlook a fundamentally important factor that affects sleep and wakefulness cycle, ease of falling asleep and daytime performance. These are circadian rhythms of the body under the control of the biological clock.This review highlights the specifics of the human biological clock and its relationship to insomnia and complaints of poor sleep. The phenomenon of the human chronotype as a set of individual preferences in sleep-wake rhythm is considered. Late chronotype, tat tends to wake up late and be active in the evening turns out to be the most vulnerable to the appearance of complaints of poor sleep and development of insomnia. This result is typical for different age groups. The reason for problems sleep for the late chronotype is the need to adjust to social demands and to fall asleep and wake up too early relative to the phase of one’s own circadian rhythm.Circadian rhythms may contribute to the formation and maintenance of insomnia. Both chronic and acute insomnia may have a chronobiological component that is not always considered. Late chronotype may be a factor further exacerbating the course of insomnia. The regularity of circadian rhythms may also be impaired in insomnia.The importance of the biological clock in the regulation of sleep and wakefulness also explains the successful approach to insomnia treatment with melatonin, which plays an important signaling role in the circadian regulation of the body.