Desynchronization of daily rest-activity rhythm in the days following light propofol anesthesia for colonoscopy.

Anesthesia and surgery are associated with fatigue and sleep disorders, suggestive of disturbance of the circadian rest-activity rhythm. Previous studies on circadian rhythm disturbance were focused on patients undergoing general anesthesia associated with surgery. This does not permit one to draw valid conclusions about the effects of general anesthesia per se on circadian rhythms. Our study was set up to determine the impact of a hypnotic dose of propofol on the circadian rest-activity rhythm in humans under real-life conditions. Seventeen healthy subjects scheduled to receive light propofol anesthesia for ambulatory colonoscopy were investigated. Their rest-activity rhythms were assessed using actigraphic monitoring. Diurnal rest was increased, whereas nocturnal sleep was unchanged in the days following anesthesia. Nonparametric analyses showed a decrease in the strength of coupling of the rhythm to stable environmental zeitgebers and increase of fragmentation of the rhythm after anesthesia. Light general anesthesia itself impairs synchronization of the circadian rest-activity rhythm to local time in patients by acting directly on the circadian clock.