Rapid Adjustment of Circadian Rhythms in Shift Worker of an Oil Refinery

Some subjects (selected shift-workers) are able to rapidly adjust (within 1 or 2 days) the timing of their physiological circadian rhythms to changes of work-rest schedule in the 24 h scale. In shift workers, able to adjust quickly, the rapid rotation of shifts (3-4 days) seems to be well tolerated from a chronophysiological point of view. This fact has to be kept in mind since, socially as well as psychologically the rapid rotation is preferred to the conventional weekly shift.