AP BIOLOGY

Detailed explanation-1: -Lactic acid is a byproduct of anaerobic metabolism, in which the body produces energy without using oxygen. Since the discovery of lactic acid, the popular notion has been that it is responsible for muscle fatigue and also tissue damage induced by the lactic acid following an intense workout.

Detailed explanation-2: -What does lactic acid do? Lactic acid is an important molecule in cellular respiration, glucose production, regulation of inflammation, and molecular signaling. Under anaerobic conditions, glucose (and more specifically, pyruvate) is converted into lactic acid in order to produce energy for the cells.

Detailed explanation-3: -Increased lactate buildup goes hand-in-hand with a drop in cell pH that occurs as a result of the hydrogen ion separating from lactic acid. This hydrogen ion is responsible for the muscle burn we often feel.

Detailed explanation-4: -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.