In fitness, cardio refers to any exercise that raises the heart rate and improves the efficiency of the heart, lungs, and circulatory system. Common forms of cardio include running, cycling, swimming, and aerobic workouts. These activities enhance endurance and stamina while burning calories. Moreover, consistent cardiovascular exercise supports weight management and contributes to overall health by reducing the risk of chronic diseases such as heart disease and diabetes. Assessing heart rate during cardio helps gauge exercise intensity.