Examination of mental health, sociodemographic and behavioral factors associated with vigorous physical activity among medical students.

Introduction: Although physical activity (PA) is a multidimensional behavior, most research has focused on total PA volume, meeting PA recommendations, or absolute vigorous physical activity (VPA), rather than on how VPA is distributed within total PA. Therefore, the proportion of VPA within total PA remains an underexplored feature of activity patterns. This exploratory analysis examined whether depressive symptoms and selected sociodemographic, behavioral, health and study-related characteristics were associated with different proportions of VPA within total PA among sufficiently active medical students. Methods: This was a secondary analysis of data from a cross-sectional study that included 656 sufficiently active fifth-year medical students from five universities in Serbia. PA was assessed using the International Physical Activity Questionnaire (IPAQ-SF), and depressive symptoms were measured with the Patient Health Questionnaire-9 (PHQ-9). Participants were categorized based on the proportion of VPA within total PA into three groups: no VPA contribution, low-to-moderate VPA contribution, and higher VPA contribution, corresponding to 0%, 0.01%-30%, and >30% VPA within total PA. Results: In pairwise multivariable logistic regression analyses, higher PHQ-9 scores were associated with lower odds of belonging to the 0.01%-30% VPA group than to the 0% VPA group, whereas no significant association was observed for the >30% VPA group. VPA categories were also associated with age, sex, meal frequency, alcohol use, perceived social support, and total energy expenditure. Conclusions: These findings suggest that, among sufficiently active medical students, depressive symptoms and several sociodemographic, behavioral and health characteristics are associated with differences in VPA distribution within total PA. The association with depressive symptoms was limited to the comparison between no VPA and low-to-moderate VPA proportion. Future longitudinal and experimental studies are needed to clarify these associations beyond the limitations of a cross-sectional self-reported design.