The present longitudinal study examined the associations between chronotype and two core components of job burnout - exhaustion and disengagement from work - among firefighters, and explored whether emotional demands moderate these relationships. The sample comprised 557 male firefighters who were assessed twice, with a six-month interval between measurements. Hypotheses were tested using a cross-lagged panel model. Results indicated that an evening chronotype predicted higher subsequent levels of both exhaustion and disengagement. In contrast, the reverse direction of effects - job burnout predicting later changes in chronotype - was not supported, suggesting that circadian preference may serve as an antecedent rather than a consequence of burnout. Furthermore, emotional demands moderated the association between chronotype and burnout. Specifically, firefighters with an evening chronotype who experienced high emotional demands were at the greatest risk of disengagement. However, this interaction effect was observed only for disengagement, not for exhaustion. These findings provide longitudinal evidence linking eveningness to an increased vulnerability to job burnout, particularly under emotionally demanding work conditions. The results underscore the importance of considering individual circadian preferences in occupational health research and suggest that interventions aimed at mitigating burnout should take into account both chronotype and the emotional context of work.
Circadian Biology