The Role Of Lactic Acid In Exercise

It is common, especially in medicine and sports, to hear about lactic acid. And yet, do you know what it is made of and what are its functions?

Lactic acid, or its ionized lactate form, is a chemical compound that plays an important role in different biochemical processes such as, for example, lactic acid fermentation.

One of the tissues in the body that produces the most lactic acid is muscle, as it appears after consuming carbohydrates for energy. This process is known as lactic acid fermentation. We will tell you all about this molecule in the following article.

Lactic acid production

Lactic acid is produced primarily in muscle cells and red blood cells. It is formed when the body breaks down carbohydrates for energy when oxygen levels are low. These decrease during strenuous exercise or when the person is infected or sick.

The main source of lactate is the breakdown of a carbohydrate called glycogen. This substance is a natural reserve of the body, formed by multiple chains of sugar (glucose). Its breakdown produces a lot of energy, which makes it one of the main sources of muscle.

However, using glucose requires oxygen and it’s a bit longer process. Therefore, in high intensity situations, cells shorten the path and produce energy through fermentation. It is less efficient but faster.

While some cells have the ability to use pyruvate for energy, others cannot. This is why muscle is one of the tissues where lactate production is the most important.

Lactic acid and muscles

The reason athletes can work so hard and for so long is that training allows muscles to absorb lactic acid more efficiently.

Muscle cells are able to convert glucose into lactic acid. Then, it is absorbed and used by cell organelles called mitochondria, which are responsible for producing energy in cells.

Mitochondria have a characteristic protein to transport lactic acid to their interior. As a result, intense training doubles the mass of the mitochondria and the mitochondria burn more lactic acid. As a result, the muscles work better.

Lactic acid during exercise

With training, many cells can adapt to use more pyruvate and therefore produce less lactate. In addition, as physical exercise increases, additional amounts of muscle fibers are recruited.

These fibers are little used when the person is resting or doing light activities. Many of these are quick to activate and do not have much capacity to convert pyruvate into energy. Therefore, much of the pyruvate becomes lactate.

Lactate: a very dynamic substance

When lactate is produced, it attempts to leave the muscles and enter other nearby muscles, such as the blood stream or the space between muscle cells, where the concentration of lactate is lower.

When lactic acid enters another muscle, it can be converted back to pyruvate so that it can be used for aerobic energy.

Lactate is also used by the heart for fuel. In turn, it can go to the liver to return to glucose and glycogen and thus start the cycle again.

Finally, you can also quickly travel from one part of the body to another. There is even evidence that certain amounts of lactate are converted back to glycogen in muscles, without necessarily going to the liver.