Characteristics of Sleep States, Sleepiness and Fatigue among Nurses Working in 12-hour Double Shifts

Abstract

Purpose: The present study aimed to elucidate sleep states, sleepiness, and fatigue among nurses working 12-hour double, day, full day, and night shifts using subjective and objective indicators. Methods: Sleep states, sleepiness, and fatigue during day, full day, and night shifts were measured in seven 22-year-old female nurses using the Kwansei Gakuin Sleepiness Scale (KSS), the Subjective Fatigue Questionnaire (Jikaku Sho Shirabe), the Psychomotor Vigilance Task (PVT), and an Active Tracer (GMS Inc., Tokyo, Japan). The nurses also wore an ActiGraph for four days at the end of their shifts for a total of seven days. Results: A full day shift required more physical activity than day or night shifts. Fatigue and sleepiness did not change during day or night shifts. Fatigue and sleepiness increased during the full day shift and arousal linearly decreased at the end of the shift. Meanwhile, nurses on night shift had less sleepiness and fatigue at the start of the shift, but drowsiness, eyestrain, and fatigue were increased at the end of the shift. The nurses slept for shorter periods before a night shift than after a day shift. Furthermore, sleep-wake rhythms temporarily changed after night shifts but recovered on the following day. Conclusions: The nurses were more active during 12-hour double and full day shifts than any other shifts, but fatigue was increased and arousal was decreased. The nurses slept for shorter periods before night shifts than after day shifts.