Cardiorespiratory fitness (CRF) is associated with referring to enhance oxygen transport capacity to respiratory systems and increasing oxygen transport circulatory to skeletal muscle to produce energy. The aim of this report on the health-related CRF in the oxygen transport system-mediated physiological nitric oxide (NO) functional adaptations. Therefore, we want to know that swimming exercise-induced improvements in CRF resulted in increased oxygen transport capacity during physical activity of the respiratory systems. Therefore, the oxygen circulatory transport system is related to NO signaling and has been associated with various pathophysiologic functions and neuronal activity. Besides mediating normal functions, NO is implicated in inflammation and hypertension disease states. Swimming exercise is a good way to increase the rate of metabolism. Swimming exercise improves heart rate and oxygen circulatory, and increases the rate of metabolism and burning of heat. In this context, this review summarizes the roles of NO in improvements in cardiorespiratory fitness.