Chronobiology international
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Fatigue is recognized as an important safety concern in the transportation industry. In this study, our goal was to investigate how circadian and sleep-wake dependent factors influence St-Lawrence River pilots' sleep-wake cycle, alertness and psychomotor performance levels at work. A total of 18 male St-Lawrence River ship pilots were recruited to a 16-21-day field study. ⋯ In individuals, earlier phases in psychomotor performance were correlated with earlier chronotype. This study indicates that both circadian and homeostatic processes modulate alertness and psychomotor performance levels with worst levels reached when long shifts ended in the morning. This work has potential applications as it indicates fatigue countermeasures considering both processes are scientifically based.