What is the main consequence of lactic acid accumulation during intense exercise?

Lactic acid accumulation during intense exercise primarily leads to decreased muscle contraction. As muscles undergo anaerobic respiration due to insufficient oxygen supply during high-intensity activities, lactic acid is produced as a byproduct. This accumulation can contribute to muscular fatigue and a decrease in performance.

When lactic acid levels rise, it can interfere with the muscle's ability to effectively contract by altering the pH within muscle tissues. The accumulation of protons (H+) associated with lactic acid lowers the pH, leading to an acidic environment that affects the function of enzymes involved in muscle contractions and can inhibit the release of calcium from the sarcoplasmic reticulum, which is essential for muscle contraction. Consequently, the intensity and duration of muscle contractions may decrease, leading to fatigue.