Contrary to common belief Lactic acid (lactate) is:
- NOT responsible for the burn in the leg muscles when exercising very fast
- NOT responsible for the soreness you experience in the 48 hours following a hard session
- NOT a waste product
Lactate, which is produced by the body all day long, is resynthesized by the liver to form glucose that provides you with more energy. Sounds like a friend to me.
Here is what is really happening…
The lactate shuttle involves the following series of events:
- As we exercise a chemical called pyruvate is formed…
- When insufficient oxygen is available to break down the pyruvate then lactate is produced…
- Lactate enters the surrounding muscle cells, tissue and blood…
- The muscle cells and tissues receiving the lactate either breakdown the lactate to fuel (ATP) for immediate use or use it in the creation of glycogen…
- The glycogen then remains in the cells until energy is required.
65% of lactic acid is converted to carbon dioxide and water, 20% into glycogen, 10% into protein and 5% into glucose.
It has been estimated that about 50% of the lactate produced during intensive exercise is used by muscles to form glycogen which acts as a metabolic fuel to sustain exercise.
The breakdown of glucose or glycogen produces lactate and hydronium ions – for each lactate molecule, one hydrogen ion is formed. The presence of hydronium ions, NOT lactate, makes the muscle acidic that will eventually halt muscle function. As hydrogen ion concentrations increase the blood and muscle become acidic. This acidic environment will slow down enzyme activity and ultimately the breakdown of glucose itself. Acidic muscles will aggravate associated nerve endings causing pain and increase irritation of the central nervous system.
So next time someone tells you they’re sore from lactic acid say hey, “cite your source”!