What does VO2 max represent?

VO2 max represents the maximum amount of oxygen the body can utilize during intense exercise, making it a critical measure of cardiovascular fitness and aerobic endurance. This value is usually expressed in milliliters of oxygen consumed per kilogram of body weight per minute (ml/kg/min). It indicates the efficiency with which the body can take in and use oxygen, which is vital for sustained physical activity, especially during prolonged exercise at high intensity.

In essence, a higher VO2 max reflects a greater capacity for physical exertion, as it signifies that the body can transport and utilize oxygen more effectively. Athletes often strive to improve their VO2 max through training, as it plays a significant role in performance in endurance sports.

The other choices provided refer to different physiological metrics that do not accurately define VO2 max, focusing instead on heart rate or energy expenditure, which are distinct from the body's oxygen utilization capabilities.