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Abstract Introduction Night-shift work is associated with detrimental health effects, such as sleep disorders and cardiometabolic diseases. Targeting impaired sleep of night-shift workers may be useful in preventing (long-term) health problems. Therefore, the Kairos-study aims to investigate the effect of two sleep interventions on sleep, alertness, and metabolic health in night shift workers. Methods/Results The design is a randomized controlled trial with three study arms: a split-sleep group (receives advice on splitting daytime sleep into two blocks of sleep, before and in between consecutive night shifts), a powernap group (receives advice on taking a 20-minute powernap during night shifts), and a control group. Every group will consist of 30 night-shift workers aged 18-60 years (n=90 in total). Participants will be measured at baseline (before the intervention starts), at the start of the intervention, 3 and 6 months after the start of the intervention, and 12 and 24 months after baseline. The primary outcomes are objectively-measured quantity of sleep (actigraphy) and alertness (psychomotor vigilance task) during night shifts. Secondary outcomes include quality of sleep, subjective alertness, and a set of relevant clinical biomarkers of metabolic health. Outcomes will be compared between intervention groups and control group. Discussion/Conclusion Night-shift work is prevalent and difficult to limit in our 24/7 society, yet there is currently limited evidence on effective interventions to prevent negative health consequences of night-shift work in a real-life context. The Kairos-study will contribute to this need by evaluating the effects of two promising sleep interventions aiming to improve sleep, alertness, and metabolic health in night-shift workers.
Loef et al. (Mon,) studied this question.