[Biological rhythms associated with sleep and psychological adjustment]

Because of their influence on psychological adaptation, biological rhythms associated with sleep have received growing attention during the last two decades. We are presenting an outline of (1) the ultradian rhythms of rapid-eye-movement (REM) sleep and of slow wave sleep (SWS), (2) the circadian rhythms of sleep/wake, body temperature and melatonine secretion, and (3) the infradian rhythms of the menstrual cycle and seasonal affective disorders emphasizing their importance in psychological adaptation. Particular attention is given to the consequences of the desynchronization of the circadian phase of sleeping and waking with that of core body temperature observed in the cases of abrupt time zone changes, shift work and some forms of insomnia and depression. New methods of intervention, such as the use of exposure to bright lights are discussed. A case is made for increased attention to a new form of hygiene, that of the biological rhythms associated with sleeping and waking.