Individual differences in night and continuously-rotating shiftwork: seeking anticipatory rather than compensatory strategy.

Individual differences in adaptation to night or continuously-rotating shiftwork may reflect distinct strategies of coping with temporal challenges of the environment. Rather than studying compensatory mechanisms, we have chosen the anticipatory response of the sleep onset time preceding work in order to reveal the strategy used by workers submitted to those shift systems including night work. Comprehensive interviews, taking into account several aspects of the workers' lives, allowed for a classification of the subjects in terms of adaptation to their working schedules. Night workers go to bed once a day, whereas shiftworkers prefer to allocate their sleep onsets to two different periods of the day. For both cases, the more well-adapted an individual is, according to the classification obtained by the interviews, the more regular will be the choice of sleep onset times.