Lactic Acid Build-up with Decreasing Oxygen
As the concentration of oxygen within a muscle cell decreases, the concentration of lactic acid increases. This is due to a shift in the cell’s metabolic processes from aerobic respiration to anaerobic respiration.
Here’s the breakdown:
- Normal (sufficient oxygen): Cells primarily use aerobic respiration to generate ATP (energy). This process efficiently breaks down glucose using oxygen, producing carbon dioxide and water as byproducts.
- Low oxygen: When oxygen becomes limited, cells switch to anaerobic respiration to continue generating ATP, though less efficiently. This process, known as lactic acid fermentation, breaks down glucose without oxygen, producing lactic acid as a byproduct.
Consequences of Lactic Acid Build-up:
- Muscle fatigue and soreness: Lactic acid build-up contributes to the burning sensation and fatigue experienced during intense exercise.
- Acidosis: Excessive lactic acid can lower the pH within the muscle cells, leading to acidosis. This can further impair muscle function and cause discomfort.
Recovery:
- When oxygen levels are restored, such as during rest periods, the accumulated lactic acid is gradually cleared from the muscles. The liver plays a key role in this process, converting lactate back into glucose.