Sleep Deprivations and Irregular Work Schedules

Abstract

Chronobiological studies show that irregular schedules lead to troubles of biological rhythms, especially of sleep-wake cycles, and arousal. The aim of the present research is to evaluate the sleep perturbations due to irregular work schedules in transport operations. The global investigation concerns sleepiness during activity as well as sleep deprivation during rest period. This paper is focused on the sleep durations for two kinds of operators: aircrews during long-haul routes and drivers for ground transport. Sleep duration was evaluated by means of wrist motor activity. For ground transport drivers, results show a strong reduction of sleep duration during day-time rests. This sleep deprivation can reach 50 percent for almost all drivers studied. These results confirm that the sleep duration is determined by the rest starting time. Sleep periods during day-time rests are organized into naps and sleep, during night-time, rests are characterized by continuous sleep. For aircrews, sleep duration during layover periods is generally normal after a north-south trip. After an eastbound or a westbound trip, a rebound effect of sleep deprivation was noted as well as poor sleep quality.