AP BIOLOGY

Detailed explanation-1: -This burning sensation is associated with a buildup of acid in the muscles during intense exercise, and lactic acid has long been thought to be the culprit in that acid buildup, known as acidosis. Lactic acid is a byproduct of anaerobic metabolism, in which the body produces energy without using oxygen.

Detailed explanation-2: -During intense exercise, there may not be enough oxygen available to complete the process, so a substance called lactate is made. Your body can convert this lactate to energy without using oxygen. But this lactate or lactic acid can build up in your bloodstream faster than you can burn it off.

Detailed explanation-3: -Lactic acid is formed and accumulated in the muscle under conditions of high energy demand, rapid fluctuations of the energy requirement and insufficient supply of O2. During intense exercise sustained to fatigue muscle pH decreases to about 6.4-6.6.

Detailed explanation-4: -The lactate concentration during exercise significantly increased compared to the basal level (p<0.05 or p<0.001).

Detailed explanation-5: -Contrary to belief, lactic acid does not cause muscle soreness. However, the concentration of lactic acid in the blood does increase during exercise. High levels of lactic acid in the blood can lead to hyperlactatemia and lactic acidosis.