Lactate and Lactic Acid
You have undoubtedly heard your coach or trainer use the word lactic acid and lactate interchangeably. Many believe these two things are the same, but they are very different. We understand that the term “lactic acid” has been used in practice for over 100 years. There is no such entity as lactic acid in any living cell or physiological system. It is impossible, based on the fundamental laws of physics that underpin biochemistry, physiology, or acid-base chemistry where cells present in living systems are regulated between a pH of 6.0 and 7.45. Lactate is produced by your body in response to aerobic exercise and serves as a fuel to muscles and especially the heart. During exercise, you are using oxygen at higher rates. As we discussed, the body is always using aerobic and anaerobic metabolisms synchronously. When the body’s anaerobic system increases, the body turns a compound called pyruvate which participates in the Citric Acid Cycle, into lactate. Lactate is then used as another source of energy for short periods of time. As the muscles continue to work, or your power reserve is not sufficient, the acidity levels rise, again having nothing to do with lactic acid. The muscles begin to fail and lose power. Lactate helps to counter effect the activation of the muscle cells, which is often felt as the burn when you cannot continue to run at the same pace.
Therefore, as you train your power reserve, levels of lactate well above 4 mmol/L are not at all uncommon. Lactate production is a protective mechanism that prevents the body from going to far. When you push yourself to hard, it is not the level of lactate that causes you muscle pain, rather it is physical damage to micro tears in the muscle fibrils themselves. The better you can process lactate; the greater will be your power reserve and ability to vary your pace and run faster. Intracellular and extracellular lipid molecules usually supply between 30 and 80% of the energy for biologic work, depending on three factors:
1. Individual nutrition status and insulin sensitivity
2. Current training level
3. Intensity and duration of physical activity