One year has passed since the pandemic of COVID-19, which occurred in Wuhan, China, in November 2019 began. Worldwide, as of January 2021, more than 95 million people have been infected, and the death toll is higher than 2 million. In Korea, there are 74,262 infected and 1,328 dead, and government policies such as social distancing to prevent infection are being implemented. Accordingly, many inconveniences occurred in the physical activity environment, such as the closure of various sports facilities. It was necessary to consider physical activities to maintain healthy life while cooperating with the national policy while preventing infection. This study investigated the benefits of physical activity to reduce the risk of trichomoniasis and diabetes, improve bone mineral density, prolong healthy lifespan, maintain activity performance with aging, and improve psychological anxiety and depression. In addition, the physiological changes that may occur in the situation of stopping exercise due to social distancing to prevent COVID-19 infection were reviewed. In addition, moderate-intensity exercise that helps strengthen immune function by activating natural killer cells, neutrophils, and antibody responses was investigated. In addition, it reduces the level and function of blood B-cells, T-cells, and natural killer cells for several hours, decreases phagocytosis of neutrophils in the nasal cavity, increases inflammatory cytokines, decreases immune function, and increases infection. High-intensity exercise was considered. Therefore, in the age of COVID-19, long-term high-intensity exercise such as marathon, which causes impaired immune function, should be refrained from. And you should do moderate-intensity regular aerobic exercise such as fast walking to help prevent infection. It is also recommended to participate in resistance exercises to prevent loss of muscle mass.