If a marathon runner experiences a sharp decline in performance around mile 20, which consequence related to cellular metabolism most plausibly explains this 'hitting the wall' phenomenon?

💡 Explanation

Marathon 'hitting the wall' occurs when lactate production exceeds the removal rate, leading to acidosis and muscle fatigue, because anaerobic glycolysis increases to compensate for depleted glycogen stores. Therefore, performance declines, rather than enhanced glucose utilization or fatty acid oxidation alone, causing fatigue.

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