[Problems of circadian periodicity and its disorders (author's transl)]

The human circadian system controlling the variety of overt 24-h rhythms consists of some different oscillators which are separately self-sustained. Normally, all oscillators run synchronously to each other; under certain external and internal conditions (e.g. increasing score of neuroticism, or old age), however, they run in the steady state with different periods. The necessary synchronization of the endogenously driven oscillators to the environment is effected, in man, essentially by social timing mechanisms; their efficiency presupposes the possibility as well as the ability to establish social contacts. A timing mechanism may synchronize the circadian system only partially; as a result, only several oscillators are synchronized whereas others persist ot run autonomously. The different rhythm disorders, internal or external desynchronizations, when effective for a long time, may be sources of ill health.