Abstract
We reviewed the physical activity research conducted during the SARS and COVID-19 pandemic, and investigated the impact of COVID-19 pandemic on physical activity. According to an international study using smartphone applications, the number of steps decreased the most under lockdown and restrictions compared to the pre-COVID-19 pandemic, but the extent of the decrease differed between countries. In Japan, the number of daily steps decreased by about 30% around the time of the declaration of the state of emergency in April compared to the COVID-19 epidemic in early February. In addition, a body of Internet surveys reported an increase in sedentary behavior and a decrease in moderate-to-vigorous physical activity during the COVID-19 pandemic. However, these studies only represent a temporal situation under lockdown and restrictions. Therefore, the impact of the COVID-19 pandemic and lifestyle changes on physical activity needs to be determined with a long-term perspective in the future. Although Internet surveys and wearable device-based physical activity research is useful for understanding the situation in real time, caution should be paid to interpret the data because of possible selection bias.
