What is the purpose of lactic acid in the context of muscle fatigue ? How is it beneficial for performance ?
In: Biology
Cells operate off a common fuel, ATP, which is used to do any number of things. Run chemical “pumps”, divide, or change shape for muscle cells. ATP is produced in a cell component called mitochondria – commonly referred to as the “powerhouse of the cell” – however, there are different ways to produce ATP. The most common and efficient in humans is called aerobic respiration – aerobic means the process consumes oxygen, delivered to cells from the lungs through the iron rich cells in the blood.
That delivery mechanism can be a bottle neck though. During high exertion, cells require ATP at faster rates than the blood can provide oxygen. While they can store a very short term supply for use in critical times, ultimately backup production is necessary. This back up plan is “anaerobic respiration,” or metabolism without oxygen. It’s less efficient but allows cells to function in an oxygen deficient environment. However, it has a byproduct – lactic acid. The body can process this out of cells, but it takes time.
As an extension, recent research has found that the human brain can actually use lactate – the specific byproduct of anaerobic respiration – as cellular food. This has the twofold effect of maintaining brain function during sustained exertion and sustaining glucose – blood sugar, what cells breakdown into ATP – for the rest of the body.
it’s not “beneficial”, but it’s a natural result of the metabolic process.
lactic acid is the result of anaerobic metabolism. usually, muscles use oxygen to covert glucose to energy. when a muscle needs a bunch of energy really fast, it’s own oxygen reserves can’t keep up. then, the muscle switches over to the anaerobic metabolism. this is far less efficient than the aerobic metabolism and leaves it with a bunch of lactic acid, but it’s better than nothing.
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