LAUSR

Abstract Objectives The unprecedented coronavirus disease 2019 (COVID‐19) pandemic and the corresponding government state of emergency have dramatically changed our workstyle, particularly through implementing teleworking and social distancing. We investigated the degree to which people's work performance is affected and the association between sedentary behavior under the state of emergency and worsened work performance during the COVID‐19 pandemic, as previous studies have suggested that sedentary behavior decreases work performance. Methods We used data from the Japan “COVID‐19 and Society” Internet Survey (JACSIS) study, a cross‐sectional, web‐based, self‐reported questionnaire survey. The main outcome was change in work performance after the COVID‐19 pandemic compared with that before the pandemic. We analyzed the association between the change in work performance and sitting duration under the state of emergency, adjusted for work‐related stress, participants’ demographics, socio‐economic status, health‐related characteristics, and personality. Results The change of work environment from the pandemic decreased work performance in 15% of workers, which was 3.6 times greater than the number of workers reporting increased performance in 14 648 workers (6134 women and 8514 men). Although telework both improved and worsened performance (odds ratio [OR], 95% confidence interval [CI] = 2.0, 1.6‐2.5 and 1.7, 1.5‐1.9, respectively), sitting for long periods after the state of emergency was significantly associated only with worsened performance (OR, 95% CI = 1.8, 1.5‐2.2) in a dose–response manner. Conclusion Sitting duration is likely a risk barometer of worsened work performance under uncertain working situations, such as the COVID‐19 pandemic.