Impact Of Occupational Physical Activity On Cardiometabolic Health In Japanese Workers

The "physical activity paradox" refers to the phenomenon where leisure-time physical activity (LTPA) is beneficial to health, while occupational physical activity (OPA) may have adverse effects. However, most of the current evidence supporting this claim is primarily based on data from Western countries. PURPOSE: This study investigated the association between LTPA on workdays, OPA, and cardiometabolic health (CMH) in Japanese workers. METHODS: In this cross-sectional study, data from accelerometers (HJA-750, Omron Healthcare) were used for 1,190 workers (652 men, 538 women) who had at least 4 workdays in a week. We measured time spent in sedentary behavior (SB, ≤1.5 METs), light-intensity physical activity (LPA), and moderate-to-vigorous physical activity (MVPA, ≥3 METs ) during working time and leisure-time on workdays. Total PA for each domain was calculated as the sum of LPA and MVPA. CMH indicators were obtained from the annual health check-up data. Participants were categorized into three clusters using K-means clustering based on LTPA and OPA: Cluster 1 (low LTPA and low OPA), Cluster 2 (high LTPA and low OPA), and Cluster 3 (low LTPA and high OPA). Multiple linear regression models were used to examine the associations between LTPA, OPA, CMH score and indicators, adjusting with age, education level, industry, medication, total wearing time, alcohol consumption, smoking, and exercise habits. RESULTS: The mean age of the participants was 45.3 ± 7.2 years. During the working time, SB accounted for approximately 73% in Cluster 1, 63% in Cluster 2, and 38% in Cluster 3. Conversely, PA during the working time accounted for approximately 27% in Cluster 1, 37% in Cluster 2, and 61% in Cluster 3. Multiple regression analysis showed that Cluster 3 (high OPA) had a significantly lower CMH score (β = -0.22; 95% confidence interval [CI] = -0.37, -0.08), along with lower values of waist circumference, triglycerides, HDL-cholesterol, and blood glucose, compared to Cluster 1 (low LTPA and OPA) in men. However, such significant associations were not observed in Cluster 2 (high LTPA) in men, and there were no significant findings in women. CONCLUSIONS: Our findings suggested that less SB and more PA during working time may effectively manage CMH among male workers.