The impact of a sleep intervention on shift workers: improved subjective sleep without objective changes: abstract

Objective Shift work is associated with disturbed sleep and adverse health effects. The aim of this study is to analyze the effects of two interventions, i.e. personalized sleep or nutritional advice, on sleep duration and quality in real-life shift workers. Methods This controlled intervention study included 57 healthy shift workers working 12-hour shifts. Participants received tailored advice based on their work schedule, social obligations, and physiological markers. The sleep advice focused on sleep timing, multiple sleep episodes, and sleep hygiene education, while the nutritional guidance structured meal timing, macronutrient distribution, and energy intake. Sleep was assessed objectively through actigraphy at baseline, start intervention and post-intervention (averaging 13 night shifts, 6 early shifts and 20 free days per participant). Subjective sleep was measured with the Insomnia Severity Index at baseline, post-intervention and follow-up. Mixed-effects models with a random intercept were used, adjusted for age, chronotype and household. Results Participants experienced on average shorter sleep duration when working night and early shifts, compared to recovery days. Neither intervention changed the objective sleep duration or quality. Participants who received the sleep advice had significantly higher insomnia scores at baseline, and their scores had decreased to match those of the other groups on post-intervention and during follow-up 8 months after the intervention. No such effects were observed for the nutritional guidance. Conclusion Personalized sleep guidance improved subjective sleep experience (insomnia scores) but had no effect on objective sleep measures, highlighting the disconnect between subjective experience and objective sleep metrics.
Abstract from: 30th Epidemiology in Occupational Health Conference (EPICOH 2025), Hosted by Institute for Risk Assessment Sciences, Utrecht University, 6–9 OCTOBER 2025, Utrecht, the Netherlands