What does oxygen debt refer to in exercise recovery?

Oxygen debt refers to the period after exercise when the body requires additional oxygen to replenish its energy stores and restore physiological balance. Specifically, this term describes the amount of oxygen used during the recovery phase that exceeds the normal resting levels. When you engage in intense physical activity, your body uses more oxygen than it can take in, leading to a state where it temporarily "borrows" oxygen from the anaerobic systems.

After the exercise stops, the body enters a recovery phase where it continues to consume oxygen to convert lactate back into glucose and to restore energy reserves such as ATP and phosphocreatine. This elevated oxygen consumption during recovery is essential for clearing out metabolic byproducts and returning the body to its pre-exercise state. Therefore, recognizing that oxygen debt is specifically about the excess oxygen consumed post-exercise makes it clear why this option is accurate.