Lactic acid

Share This
« Back to Glossary Index

What is lactic acid?

Lactic acid is a chemical that builds up in muscle during the anaerobic type of exercise where the body struggles to obtain enough oxygen. When this chemical builds up in muscle, you are likely to experience the ‘burny’ feeling making it hard to exercise.

How does the body produce lactic acid?

During the day, our body will be fueling our tasks or exercise using the aerobic energy system which works in the presence of oxygen. This energy system uses mostly carbs for energy, and these are obtained from a series of chemical reactions such as glycolysis. The outcome of this process is the pyruvic acid to produce more energy. However, this energy can only be produced from the pyruvic acid in the presence of oxygen. This means that this energy system is used by the body when you are performing light to medium intensity exercise.

However, this changes when you perform high to very high-intensity exercises like all-out sprints where you push yourself to the point of breathlessness. So, for the body to sustain your energy levels and enable those short-bursts of high-intensity energy, muscle skips harvesting the energy from pyruvic acid, and instead, the pyruvic acid gets converted into a waste product – lactic acid which is then released into the bloodstream to provide energy for the working muscle. This provides a ‘burning’ sensation in muscle and causing fatigue.

Although lactic acid builds up during exercise, it returns to stable levels when the body rests.

« Back to Glossary Index