During heavy muscular exercise when oxygen supply is insufficient, pyruvate is converted into which organic compound causing muscle fatigue?

💡 Solution & Explanation

In anaerobic conditions during strenuous physical exertion, human muscle cells break down glucose into pyruvate and subsequently convert it into lactic acid due to temporary oxygen debt. The accumulation of lactic acid leads to painful muscle cramps and fatigue. Yeast cells convert pyruvate into ethanol and carbon dioxide during fermentation instead.