Associations between Work Schedule Type and Physical Activity with Mental Health and Job Stress among Seoul Metro Employees

Background: Shift-based occupations have been consistently linked to adverse psychological outcomes; however, limited research has examined how work schedule type and physical activity are jointly associated with mental health and job stress in public transportation employees, a population frequently exposed to irregular hours and safety-critical responsibilities. This study investigated the associations between work schedule type and physical activity with mental health indicators and job stress among Seoul Metro employees. Methods: A cross-sectional survey was administered to 298 full-time male employees of Seoul Metro. Participants were categorized by work schedule (shift vs. regular) and physical activity level (regular, irregular, none) following American College of Sports Medicine (ACSM) guidelines. Mental health (sleep disturbance, depression, anxiety, loneliness) was assessed using validated binary indicators, and job stress was measured with the Korean Occupational Stress Scale–Short Form (KOSS-SF). Group differences were analyzed using chi-square tests, t-tests, and one-way ANOVA with effect sizes, and binary logistic and multiple regression analyses were conducted to identify predictors. Results: Shift workers reported significantly higher sleep disturbance and anxiety compared to regular daytime workers (p < 0.05). Employees who participated in regular physical activity had lower odds of sleep disturbance and depression (p < 0.05) and showed lower job stress scores compared with inactive workers. Work schedule type and physical activity were independently associated with mental health and job stress among transit employees. Conclusion: These findings underscore the dual influence of work schedule and physical activity on the psychological and occupational well-being of public transit employees. Promoting regular physical activity may buffer occupational stress among employees engaged in shift-based work. Workplace interventions that support physical activity participation and improve shift planning may enhance employee well-being.