RESUMO
This study compared the effects of an uncommon 4 x 6-hour shift system used by some French customs units with the situation of customs officers working on two other shift systems (3 x 8 hours and 2 x 12 hours) and a group of day workers. Data were collected by a questionnaire on shift schedules, working hours, sleep, health, and off-the-job activities, and by time-budgets over four days and actigraphic recordings over five days. The 4 x 6-hour-shift officers reported a high proportion of sleep difficulties and digestive disturbances. Their situation was very similar to that of 3 x 8-hour shift workers and contrasted markedly with that of 2 x 12-hour workers and day workers. Three factors were critical: the irregularity of eating habits imposed by four different shifts, the greater number of working days in the week, and the frequent assignment of two shifts on the same day.
