Outline how the oxygen debt is removed after exercise, limited to: (a) continuation of fast heart rate to transport lactic acid in blood from muscles to the liver (b) continuation of deeper and faster breathing to supply oxygen for the breakdown of lactic acid in the liver

After vigorous exercise, the body enters a recovery phase where it works to remove the accumulated lactic acid and repay the oxygen debt incurred during anaerobic respiration. This process involves two key physiological responses:

(a) Continuation of Fast Heart Rate

• Increased Blood Flow: After exercise, the heart rate remains elevated to ensure that blood continues to circulate rapidly throughout the body. This increased circulation is crucial for transporting lactic acid from the muscles, where it was produced, to the liver.
• Lactic Acid Transport: The lactic acid generated during anaerobic respiration is transported via the bloodstream to the liver. Here, it can be converted back into glucose through a process known as gluconeogenesis or further metabolized to pyruvate for energy production. This helps clear lactic acid from the muscles, reducing fatigue and discomfort.

(b) Continuation of Deeper and Faster Breathing

• Increased Oxygen Supply: Following intense exercise, breathing rate and depth increase significantly. This response ensures that more oxygen is taken in to meet the elevated metabolic demands of recovery.
• Breakdown of Lactic Acid: The additional oxygen is essential for the breakdown of lactic acid in the liver. In aerobic conditions, lactic acid can be fully oxidized into carbon dioxide and water, which are easily expelled from the body. The increased oxygen supply facilitates this process, enabling efficient removal of lactic acid and restoration of normal metabolic functions.