Factors Influencing Recovery from Fatigue after a 16-hour Night Shift among Female Japanese Nurses

Background: The present study aimed to evaluate self-reported fatigue recovery among Japanese nurses who perform shift work and to evaluate how their fatigue was affected by a day off after a night shift. Methods: We recruited 66 healthy female Japanese nurses at three regional private hospitals. The nurses were divided into a recovery group and a non-recovery group, based on their self-reported experience of fatigue during the interval from the time before their night shift to after a following day off. Unpaired t-test and logistic regression analyses were used to find associations of self-reported fatigue with demographic and lifestyle factors. Results: The recovery group included 45 nurses, and the non-recovering group included 21 nurses. The recovery group exhibited a high degree of fatigue at five assessment points, while the non-recovery group only exhibited a high degree of fatigue at the post–day off assessment. The adjusted odds ratios (95% confidence intervals) for self-reported fatigue during the night shift were 1.27 (1.00–1.61) for the age of the nurse’s youngest child and 1.04 (1.00–1.08) for the nurse’s time spent napping (P < 0.05). Conclusion: Sleeping before a night shift may facilitate recovery after the shift, although fatigue was also influenced by the age of the nurse’s youngest child and the nurse’s napping time.