A nurse is attempting to improve his overall health status. Which of the following is the best cardiorespiratory fitness activity?

A. Bicycling is an aerobic exercise that elevates heart rate and improves cardiorespiratory fitness, endurance, and oxygen utilization. Regular structured aerobic activity, such as a class three times weekly, provides measurable improvements in cardiac and pulmonary function, making it the best choice for enhancing overall cardiovascular health. B. Resistance training primarily builds muscular strength and endurance, improves metabolism, and supports bone health. While it has cardiovascular benefits indirectly, it is not as effective as aerobic exercise for improving cardiorespiratory fitness. C. Walking 10,000 steps per day promotes general health and can contribute to physical activity goals, but unless performed at a moderate to vigorous pace, it may not sufficiently challenge the cardiovascular system to significantly improve cardiorespiratory fitness.