The production of lactate, commonly mistaken as lactic acid, is one of the most misunderstood processes of the human body. The formation of this lactate molecule results from the metabolic process known as glycolysis. During activity, the body begins to break down glycogen (sugar) to be used as fuel. This process creates ATP to be used as fuel for the body, but also the byproduct pyruvic acid and eventually lactate. Because large amounts of lactate can be found in fatigued athletes, many people assume it is the cause of the fatigue, but this may not be true.
Lactate: Good or Bad?
Because lactate is often mistaken as lactic acid, it is also associated with metabolic acidosis. However, even though larger amounts of lactate are present during metabolic acidosis, they do not hold a causal relationship with each other. Meaning, even though they are linked together, one does not cause the other. In fact, lactate actually helps buffer the body from a drop in PH (acidosis) by shuttling H+ atoms out of the cell.
An even less known fact about lactate is that it can be recycled by the body as a fuel source. During glycolysis, lactate has two options, shuttle H+ outside of the cell, or shuttle those same H+ atoms to the mitochondria to be used as a fuel source. What the body decides to do with the lactate is dependent on the intensity of the activity. During high intensity activity, the body does not have time to recycle the lactate as a fuel source, but during lower intensity activities the body has time and can convert it back into fuel.
As you can see, lactate is actually a good thing within the cell. During high intensity activity it helps slow metabolic acidosis by shuttling H+ outside of the cell. When possibly, lactate also shuttles these H+ atoms into the mitochondria, where it can be used as fuel. Both of these processes help athletes go faster and further before fatigue sets in.