RESUMEN
OBJECTIVE: Worldwide, over 70 countries advance their clocks in spring to Daylight Saving Time. Previous research has already demonstrated that the clock change negatively impacts employees at work. However, this research implicitly assumed that the clock change affects everyone to the same extent. In the current study, we propose that the massively prevalent Daylight Saving Time transition may have an effect on employees' sleep and their work engagement that is dependent upon employees' chronotype. METHODS: We conducted a longitudinal study with 155 full-time employees who filled out online surveys on three Mondays around the transition to Daylight Saving Time. RESULTS: Results showed that the transition to Daylight Saving Time resulted in decreased work engagement measured 1day as well as 1week after the transition to Daylight Saving Time. Lower sleep quality (but not shorter sleep duration) partly explained this effect. The negative effect of the transition to Daylight Saving Time on work engagement 1day after the transition was more pronounced for employees with later chronotypes ("owls") than for those with earlier chronotypes ("larks"). CONCLUSION: In summary, our study shows that the transition to Daylight Saving Time has an adverse short-time impact on private life and working life and should, therefore, also be considered in organizations. Because later chronotypes are especially prone to adverse effects of the transition, interventions targeted for this group might be especially helpful.