Effect of sleep on alertness at work among fixed night shift nurses: A prospective observational study

AIMS: To identify patterns of declining alertness at work among fixed night shift nurses using an objective measure and to determine the effect of sleep parameters on the decline in alertness at work. DESIGN: A prospective observational study. METHODS: Data were collected from 65 fixed night shift nurses who provided direct nursing care for patients in Korean hospitals between September 2020 and March 2021. Participants wore an actigraph for 14 days on their non-dominant hand to measure sleep parameters and predict their hourly alertness scores. They completed an online survey to provide their demographic information. Mixed-effect models were employed to determine the association between sleep parameters and the decline in alertness. RESULTS: The alertness scores of fixed night shift nurses constantly dropped every working hour. Scores dropped below 20% after 4 h from the beginning of the shift and below 30% after 6 h. Increased minutes in bed, minutes asleep and sleep efficiency reduced the risk of decreased alertness scores below 70. Increased sleep latency was associated with an increased risk of alertness scores dropping below 70. CONCLUSION: The alertness of fixed night shift nurses drops steeply during regular hours and remains low during overtime. Sleep parameters contribute to the decline in alertness at work among fixed night shift nurses. IMPACT: This study identified patterns of decline in alertness among fixed night shift nurses and the contributing factors for this decline, using an objective measure. The findings have important implications for the development of future interventions to improve the sleep hygiene of fixed night shift nurses to enhance their alertness at work.