Abstract：After being infected with coronavirus disease 2019 (COVID-19), the severity and mortality in individuals with obesity were significantly higher than that of non-obese individuals. Studies have confirmed that high cardiorespiratory fitness can reduce the risk of COVID-19, but the influence of cardiorespiratory fitness in individuals with obesity upon infecting COVID-19 is still unclear. The purpose of this paper is to query the Google search engine for relevant research papers using ＂COVID-19,＂ ＂obesity,＂ ＂overweight,＂ and ＂cardiorespiratory fitness＂ as keywords. The results of the study confirmed that obese individuals can significantly reduce the severity and mortality of COVID-19 through improvement of cardiorespiratory fitness via exercise or increased physical activity, even in the absence of significant weight loss. Therefore, this paper suggests that when obese individuals attempt a weight loss program incorporating diet control and regular exercise, the improvement of cardiorespiratory fitness should be the primary indicator. This will help prevent the health dangers associated with obesity more effectively. (Full text)