Excess post-exercise oxygen consumption, or EPOC, is the extra oxygen the body must take in after exercise to complete restorative processes such as reformation of creatine phosphate and clearing lactic acid back to glucose.

• A. Faster breathing during exercise
• B. Short-term oxygen debt only during activity
• C. Reformation of creatine phosphate and clearing lactic acid
• D. Immediate ATP production

Answer: (C)

EPOC measures the extra oxygen the body needs after exercise to restore systems that were taxed during effort. After intense or prolonged activity, muscle stores of phosphocreatine must be rebuilt and lactate that accumulated during exertion has to be cleared and converted back to glucose; both of these restorative steps require oxygen and occur during the recovery period. This post-exercise oxygen use also helps replenish oxygen in blood and muscle stores and brings metabolic processes back toward resting levels. The other options describe responses that happen during exercise or focus on immediate ATP production, not the oxygen demand in recovery, so they don’t capture what EPOC represents.