摘要：Background - Several non-pharmaceutical policies, which include stay-at-home orders, mobility restrictions, and quarantine, have been implemented to reduce the spread of novel coronavirus disease 2019 (COVID-19). The present study examines work style changes among company workers after COVID-19 and analyses their effects on workers’ domain-specific sedentary and active behaviours. Methods - We analysed data from a nationwide prospective online survey in Japan. The data were obtained in February 2019 (<i>n</i> = 3200) and in July 2020 (<i>n</i> = 1709) from the registered individuals of a Japanese internet research service company. The participants reported work style patterns before and after the outbreak of COVID-19 in the follow-up survey. Domain-specific sedentary behaviours and physical activities were assessed by questionnaires. Paired <i>t</i>-tests were used to compare work styles before and after the outbreak of COVID-19. Multivariable linear regression models were used to assess the associations between changes in work style and changes in sedentary behaviours and physical activities. Results. Workers had more working from home days and fewer office-based working days after the outbreak of COVID-19 (<i>p</i> < 0.001 and <i>p</i> < 0.001, respectively). The increase in the number of working from home days per week was significantly associated with increases in work-related sitting time and total sitting time (b = 0.16, 95% CI 0.08, 0.24, <i>p</i> < 0.001 and b = 0.23, 95% CI 0.11, 0.36, <i>p</i> < 0.001, respectively). However, it was also associated with a decrease in car sitting time (b = −0.04, 95% CI −0.06, -0.01, <i>p</i> < 0.001). In addition, the increase in the number of working from home days was associated with a decrease in work-related moderate physical activity (b=−0.06, 95% CI −0.10, −0.02, <i>p</i> < 0.001). Conclusions. Our study provided preliminary evidence of an increase in working from home days in response to COVID-19 in Japan and of how this increase in the number of working from home days has affected workers’ sedentary behaviours and physical activities. These findings shed light on the effects of COVID-19 on work styles and workers’ sedentary behaviours and physical activity.
