As a subject matter expert in the field of exercise physiology, I can explain that oxygen debt occurs when the body's demand for oxygen exceeds the amount of oxygen being supplied during intense physical activity. This typically happens when the muscles are working harder and faster than the cardiovascular and respiratory systems can supply oxygen through aerobic respiration. During high-intensity exercise, the body may rely on anaerobic respiration, which does not require oxygen, to produce energy quickly. However, this process is less efficient and results in the production of lactic acid, which can cause muscle fatigue and soreness. The oxygen debt is the additional amount of oxygen needed after the exercise has stopped to restore the body's oxygen levels and to convert the lactic acid back into a form that can be used for energy production through aerobic respiration. read more >>

Much less energy is released during anaerobic respiration than during aerobic respiration. This is because the breakdown of glucose is incomplete. Anaerobic respiration produces an oxygen debt. This is the amount of oxygen needed to oxidise lactic acid to carbon dioxide and water.read more >>