What is lactic acid primarily produced by?

Lactic acid is primarily produced during anaerobic respiration, which occurs when cells generate energy without sufficient oxygen. This process is especially prevalent in muscle cells during intense exercise when oxygen levels become depleted. Under these conditions, glucose is metabolized to produce energy, resulting in the accumulation of lactic acid as a byproduct. This can lead to muscle fatigue and discomfort.

While aerobic respiration and cellular metabolism typically involve oxygen and produce carbon dioxide and water as byproducts, these processes do not result in lactic acid production. Fermentation does relate closely to the production of lactic acid; however, it encompasses a broader range of anaerobic processes, some of which may not directly involve lactic acid specifically. Therefore, focusing on anaerobic respiration provides the most accurate answer regarding the primary source of lactic acid in the body.