2019 年 117 巻 p. 1-7
Installation of height-adjustable desks（HAD）are recommended to reduce sitting behaviors in the workplace. However, it is still unclear whether standing desk work using the HAD could decrease sitting time and increase physical activity（PA）during in-office working hours. This study aims to investigate the association of the usage of HADs with objectively measured sitting behaviors, or PA, among Japanese employees. This study was conducted in Tokyo in November 2018 at a single office of an office furniture manufacturing and sales company. Participants included 90 employees that completed a self-reported questionnaire survey and wore a tri-axial accelerometer to measure PA and sitting time（ST）. In the target office, electric HADs were installed on hot-desking spaces, and fixed seats which were available for all employees. Participants were divided into two groups of users or non-users of HADs based on their responses to the questionnaire. Independent t-tests were applied to examine the differences in ST and PA between HAD users and non-users for participants stratified by job type（sales work or other office work）. Among the office workers, users showed less ST and greater PA（ST: 377.4 ± 51.7, PA: 142.6 ± 51.7 min/8.67-hours）than non-users during working hours（ST: 412.0 ± 42.6, PA: 108.0 ± 42.6 min/8.67-hours）, and greater non-locomotive activities（99.7 ± 45.1 min/8.67-hours）than non-users（67.1 ± 29.1 min/8.67-hours）. HAD users showed fewer bouts of prolonged ST（consecutive ST for 30 minutes or longer）than non-users（1.2 ± 0.8 vs. 1.8 ± 0.6 time/8.67-hours）. There were no significant differences observed between the two sales groups. These results suggest that working in a standing position using an HAD effectively improves ST in office workers. On the other hand, using an HAD might enhance non-locomotive activities, such as standing or posture adjust-ments at or around the desk, but it may not enhance locomotive activities.