Chronotype prior to shift work influences outcomes: resilience as a mediator of sleep and mental health

Pre-shift work chronotype significantly influenced post-shift work sleep and mental health outcomes, with resilience serving as a key mediator. These findings highlight the potential for targeted interventions-such as resilience training or chronotype-based scheduling-to mitigate early shift work-related mental health challenges and reduce nurse turnover. Statement of Significance Previous studies examining the interaction between chronotype and shift work (SW) schedules among nurses have yielded inconsistent results, primarily because SW schedules transiently influence chronotype, and most research has focused on nurses already exposed to SW. Although chronotype is generally stable and tends to revert once an intervention (e.g. altered light exposure) ceases-highlighting its trait-like characteristic-it can still be temporarily influenced by SW exposure. Consequently, prior studies often assessed chronotypes after participants had already been exposed to SW, potentially affecting the reliability of their assessments. In our study, baseline chronotypes measured before SW exposure influenced sleep and mental health during the initial adaptation period, with resilience acting as a mediator between chronotype and these outcomes. Although we did not examine long-term outcomes following SW exposure, our findings suggest that baseline chronotype may serve as a predictive biomarker for early SW outcomes.