The physical activity paradox in Japan: associations with cardiometabolic risk

Abstract Background Work occupies a large proportion of daily life in Japan. It is therefore particularly important to understand whether occupational physical activity provides the same health benefits as leisure-time physical activity, a concept known as the “physical activity paradox”. Therefore, we aimed to examine associations between device-based physical activity at work and during leisure with cardiometabolic health in a Japanese working population. Methods A cross-sectional analysis was conducted on 1,233 Japanese workers. Physical activity and sedentary behavior during work and leisure were assessed using accelerometers for over 7 consecutive days. Based on daily activity patterns, participants were grouped into three clusters: high leisure-time physical activity (Movers), high occupational physical activity (Grinders), and high sedentary behavior (Chillers). Cardiometabolic health indicators (waist circumference, blood pressure, triglycerides, HDL cholesterol, and fasting plasma glucose) were obtained from annual health examinations and used to derive a composite cardiometabolic risk score. Associations were evaluated using multiple linear regression, adjusted for multiple confounders. Results On average, participants spent 9.7 h/day working, 6.5 h/day in leisure, and 7.8 h/day sleeping. In fully adjusted models, compared with Movers, Chillers (β = 0.19; 95% CI: 0.11–0.27) and Grinders (β = 0.20; 95% CI: 0.10–0.31) exhibited higher cardiometabolic risk scores. Conclusion Our results indicate that the domain of physical activity is of relevance for cardiometabolic health in Japanese workers. Given that work accounts for a large proportion of daily life particularly in Japan, prospective investigations of the physical activity paradox in Japanese working populations are especially important.