Occupational vs. Leisure Physical Activity: Health Impacts in Japanese workers

Background: The “physical activity paradox” concept suggests that leisure-time physical activity (LTPA) improves health, whereas occupational physical activity (OPA) might not. However, most of the current evidence investigated in Western countries, lacks comprehensive study in non-Western contexts, including Japan.
Purpose: This study examined how OPA and LTPA affect cardiometabolic health (CMH) and cardiorespiratory fitness (CRF) in Japanese workers.
Methods: Using accelerometer data (HJA-750, Omron Healthcare) from 1,316 workers with at least four workdays per week, we analyzed sedentary behavior (SB) and intensity-specific physical activity (PA) during work and leisure. The CMH indicators were derived from annual health examinations, and CRF was estimated using questionnaire-derived values. The participants were grouped into three clusters based on their LTPA and OPA levels, and their health outcomes were assessed using multiple linear regressions adjusted for demographic and lifestyle factors (age, education level, industry, medication, alcohol consumption, and smoking).
Results: The mean age of the participants was 45.5 ± 8.1 years. OPA accounted for approximately 24% of Cluster 1 (low OPA and LTPA), 34% of Cluster 2 (high LTPA), and 60% of Cluster 3 (high OPA). Conversely, LTPA accounted for approximately 27% of Cluster 1, 44% of Cluster 2, and 31% of Cluster 3, respectively. Multiple regression analysis showed that Cluster 2 had a significantly lower CMH score (β = -0.14; 95% confidence interval [CI] = -0.22, -0.07), along with lower waist circumference, triglycerides, HDL-cholesterol, and blood glucose values, compared to Cluster 1. Moreover, such significant associations were observed in CRF (β = 0.34; 95% confidence interval [CI] = 0.21, 0.46).
Conclusions: Our findings suggested that LTPA benefits the health of Japanese workers, but the results did not conclusively show that OPA is detrimental.
Practical implications: Recognizing beneficial and harmful PA patterns can promote healthier lifestyles among workers and inform global occupational health strategies.