For a long time, most people believed that when we exercise, our muscles make lactic acid, this acidifies the muscles, and the acidity contributes to contractile failure, fatigue, and delayed-onset muscle soreness. Some people still believe this.

You may have heard the argument against it from well-known figures like Andy Galpin, or, if you’re deep into the science, you may have read the work of George Brooks.

In this lesson, we are going to cover the biochemistry of lactate production. We will see that we never make lactic acid, ever. We make lactate. Making lactate is fundamentally alkalinizing.

We will take a look at the presentation of glycolysis in the Berg and Lehninger biochemistry textbooks to see that, on the one hand, they give us everything we need to know to understand that the human body never makes lactic acid, but, on the other hand, they really do not equip us well to understand where acidity does comes from during exercise. This is because they do not consider acid-base balance important enough to completely present the proton balances of the chemical reactions.

Finally, we will cover what does cause muscular fatigue, take a look at the research on lactate supplements, and come to some conclusions about the best way to manage acidity during exercise to maximize performance.

This is part of a larger course on the biochemistry of how we derive energy from food and use it to fuel our wellness, performance, and longevity. Take the full course here: