Define Aerobic Exercise or Aerobic Energy System?

To produce necessary energy, the body uses an aerobic pathway and an anaerobic pathway. Exercise that relies heavily on oxygen for the provision of energy (Aerobic pathway, Citric Acid Cycle) is called an aerobic exercise. These are generally exercises like running, swimming etc. For better performance, high V02 max is desirable. Athletes with a high V02 max maintain high intensity exercise using aerobic metabolism, thus avoid high levels of fatigue (accumulation of lactic acid) associated with anaerobic exercise.

At a point where the intensity of the activity increases to such a point where the oxygen demand of the working muscles cannot be met and muscles have to obtain the extra energy through anaerobic metabolism, using reactions that do not require oxygen. When oxygen demands exceed oxygen supply (oxygen debt) during and following prolonged exertion, lactic acid accumulates within muscle tissue and sets in fatigue. The greater the exercise intensity, greater is the lactic acid accumulation. Following maximum exercise, it may take an hour or longer to attain resting levels. Therefore, the main disadvantage of anaerobic metabolism is that it can only sustain high rates of energy production for a short period of time.