A Comparative Study on the Effects of Shift Work and Circadian Disruption on Nurses’ Sleep, Fatigue, and Cognitive Function

Background: Continuous patient care requires nurses to work in rotating and night-shifts, which may disrupt circadian rhythms and adversely affect sleep, fatigue levels, and cognitive functioning.This study aimed to compare the effects of shift-related circadian disruption on sleep quality, fatigue, and cognitive function among night-shift and morning-shift nurses.Materials and methods: A comparative cross-sectional study was conducted among 60 nurses (30 night-shift and 30 morning-shift) selected through purposive sampling.Validated instruments-including the sleep hygiene index, standard shift index, Epworth Sleepiness scale, and Montreal cognitive assessment-were administered on day 1 and day 4 of the shift cycle.Data were analyzed using independent and paired t-tests at a 0.05 level of significance.Results: By day 4, 80% of night-shift nurses reported moderate sleep disturbances, whereas 83% of morning-shift nurses reported no disturbances.Night-shift nurses demonstrated significantly higher daytime sleepiness scores (15.53 ± 2.20; p = 0.01) and poorer sleep hygiene (36.2 ± 2.63).Poor sleep hygiene showed a strong positive correlation with reduced sleep quality and was associated with a notably higher likelihood of daytime somnolence.Fatigue levels were also significantly higher among night-shift nurses.No significant between-group differences were observed in cognitive function.Conclusion: Shift-related circadian disruption is associated with poorer sleep quality, elevated fatigue, and increased daytime sleepiness among night-shift nurses compared with their morning-shift counterparts.These findings highlight the need for institutional strategies to mitigate circadian misalignment and support nurse wellbeing while maintaining quality patient care.