Socioeconomic Determinants of Physical Inactivity among Japanese Workers

Background: Half of Japanese workers are physically inactive, but there are no studies on the relation between the leisure-time physical inactivity of Japanese workers and their socioeconomic status. The proportion of female workers who are physically inactive has been larger than that of male workers. Objectives: Using micro-data from nationwide surveys in Japan, this study explored the gender differences in socioeconomic determinants of leisure-time physical inactivity. Methods: We first estimated two-stage probit least squares models to examine whether simultaneous relationships between physical inactivity and working hours existed. Second, endogenous switching models were estimated to analyze whether physical inactivity depended on poor health status. We took into account the existence of unobserved factors affecting poor health status and physical inactivity. Results: The results of two-stage probit least squares estimation did not confirm simultaneous relationships between physical inactivity and working hours. The estimation results of the endogenous switching models showed that working hours had a positive effect on poor health status, and poor health status had a positive effect on physical inactivity. Physical inactivity was strongly associated with low educational attainment and marital status. For male workers, income had a negative effect on physical inactivity at the 5 percent significance level. In contrast, female income had no effect on physical inactivity. Conclusions: There are gender differences in the association of income and physical inactivity among Japanese workers. Workers in poorer health were likely to be physically inactive. To reduce chronic diseases due to physical inactivity, more attention should be paid to the influence of income reduction on poor health in males.