Shift work is an essential component of healthcare systems but induces chronic circadian misalignment through disruption of the sleep - wake cycle, nocturnal light exposure, and desynchronization between endogenous biological rhythms and environmental time cues. Such misalignment has been associated with adverse physical and psychological health outcomes. Chronotype, reflecting intrinsic circadian phase preference, has been proposed as a potential modifier of individual responses to shift work; however, its role among shift-working healthcare professionals remains incompletely understood. This cross-sectional study investigated the associations between chronotype and health-related quality of life, depressive symptoms, and eating attitudes among 278 healthcare professionals engaged in rotating shift schedules. Chronotype was assessed using the Morningness - Eveningness Questionnaire and categorized as morning, intermediate, or evening type. Physical and mental health - related quality of life were evaluated using the SF-36, yielding Physical Component Summary (PCS) and Mental Component Summary (MCS) scores. Depressive symptoms and eating attitudes were assessed using validated questionnaires. Group differences were examined using non-parametric tests, and multivariable analyses were performed to adjust for sociodemographic variables and explore non-linear effects. Significant differences in physical health - related quality of life were observed across chronotype groups. Evening-type participants demonstrated lower PCS scores compared with morning and intermediate types ( < 0.05), particularly in the Role Physical (RP) domain. However, in multivariable regression analyses, chronotype was not a significant independent predictor of PCS, whereas age and marital status remained significant. No significant differences were observed between chronotype groups in depressive symptoms, eating attitudes, or MCS scores (all > 0.05). In conclusion, chronotype may be associated with differences in physical health - related quality of life among shift-working healthcare professionals; however, these associations appear to be influenced by sociodemographic and contextual factors rather than representing a direct relationship. These findings underscore the complexity of circadian adaptation in shift work and highlight the need for further longitudinal research. p p
