Overall physical activity, but not occupational activity, is inversely associated with mental stress in a German hospital-based cohort

Background Physical activity (PA) is a cornerstone of prevention and linked to lower risk of chronic diseases, particularly cardiovascular disease. Psychosocial and perceived stress are likewise associated with adverse cardiovascular outcomes, suggesting that stress regulation may be one pathway through which PA contributes to long-term health. However, associations may differ by activity domain, as occupational PA does not necessarily confer the same benefits as overall PA. Purpose We examined associations of overall weekly PA time and occupational PA with perceived mental stress in a German cohort. Methods Data stem from a hospital-based cross-sectional questionnaire study. Overall PA was assessed via a 6-level item (transformed to a 0–1 scale) and categorized as low, intermediate, or high. Occupational PA and weekly working hours were recorded. Analyses compared low vs high PA groups, excluding intermediate levels. Associations between PA and perceived stress were examined using pairwise correlations, t-tests, and multivariable linear regression adjusting for age, sex, BMI, education, income, working hours, medication burden, sleep, health literacy, and motivation. Perceived mental stress was summarized as a Mental Stress Score (MSS; 0–1, higher=worse), averaging four standardized domains: perceived stress (PSS-10), distress (SF-6D), depressive symptoms (PHQ-9), and health-related quality-of-life impairment (HRQoL-14). Domain scores were harmonized to a 0–1 scale; MSS was calculated if ≥3 domains were available. Results Among 591 participants, overall weekly PA time correlated inversely with MSS (r≈−0.24, p<0.001); similar results were found for PA intensity (r≈−0.20, p<0.001). Occupational PA and weekly working hours showed no associations with stress (both r≈0.01, p>0.7). Participants with high stress had significantly lower overall PA (mean difference ≈0.19, p<0.001), but comparable occupational PA (mean difference ≈−0.02, p=0.57). In multivariable regression (n=364), higher MSS remained independently associated with lower overall PA time (β≈−0.40, 95% CI −0.65 to −0.14; p=0.002), indicating that this link persisted after adjustment for sociodemographic, workload, and health factors. Conclusion In this German hospital-based cohort, higher perceived mental stress was consistently associated with lower overall physical activity, independent of demographic and health factors. In contrast, occupational PA and working hours were unrelated to stress. These findings underscore the importance of prevention strategies targeting both stress reduction and promotion of overall—not solely occupational—physical activity.