Effects on sleep-related problems and self-reported health after a change of shift schedule.

This study prospectively examined the effects of a change of shift schedule from a fast forward-rotating schedule to a slowly backward-rotating one. The initial schedule had a forward rotation from mornings to afternoons to nights over 6 consecutive days, with 2 days on each shift followed by 4 days off before the next iteration of the cycle, whereas the new schedule had a slower backward rotation from mornings to nights to afternoons, with 3 days on a given shift followed by 3 days off before the next shift. Shift workers (n = 118) were compared with a reference group of daytime workers (n = 67) from the same manufacturing plant by means of questionnaires covering subjective health, sleep and fatigue, recovery ability, satisfaction with work hours, work-family interface, and job demands, control, and support. Data were collected 6 months before implementing the new schedule and at a follow-up 15 months later. As predicted, on most dimensions measured the shift workers displayed clear improvements from initially poorer scores than daytime workers, and the daytime workers displayed no improvements.