Lactic Acid

Lactic acid is one of the most misunderstood topics in nutritional science. For the nutritionist and athlete it used to be common to think lactic acid was the “reason” or “cause” behind the burn you feel when you get fatigued during high intensity exercise. This is actually the complete OPPOSITE, and gives lactic acid a bad rep.

To understand the importance of lactic acid you need some basic knowledge in the energy pathways:

There are 3 energy pathways which are “turned on” based on the amount of energy required (intensity) and the amount of time you are doing the work (duration). The first pathway is called the “ATP-PCr” system.



This energy system is what is responsible for your max clean and jerks, heavy back squats and short sprints. It is the first energy system “turned on” and provides the most muscle contraction.

This system works to create ATP (your body’s fuel source) by breaking the bonds between creatine (Cr) and phosphate (P) that are already joined together as phosophocreatine (PCr). This energy, released by the breaking of the bonds (As well as the new phosphate molecules) help to regenerate new ATP so that energy supply can meet the demand of your workout. This is partly why CREATINE plays a big part in strength gains.

This system, as powerful as it is, lasts only 10 seconds. As energy demand increases, the process of using creatine bonds gets too slow, which then bring us to the next pathway, where the key to lactic acid comes in:


Glycolic Pathway-

After those initial 10 seconds the glycolytic pathway “turns on”. Instead of creatine, the main source of this pathway is carbohydrates, or glucose. In fact “Glycolitic” literally means the breaking of glucose.

This system is much more complex than the ATP-PCr system and utilizes 10 enzymatically controlled chemical reactions to regenerate ATP. Specifically, this process regenerates four molecules of ATP for every 1 molecule of glucose put into the system. Since the “system” itself costs 2 ATP it leaves us with 2 ATP molecules to use as fuel. Also created in this process are two chemicals called pyruvate and NADH.


Lactic Acid: Saves you from “feeling the burn”

As the glycolic pathway runs quickly, as it would during CrossFit type workouts, a lot of pyruvate is released as well as hydrogen ions (as a byproduct of breaking chemical bonds). Since hydrogen atoms can quickly fatigue muscle cells, this rapid rate of hydrogen release must be “buffered”.

This is where pyruvate and NADH come to the scene. These two chemicals act quickly to “grab” these hydrogen atoms as fast as they can and export them out of our cells. When this process happens NADH becomes NAD+ and pyruvate becomes the infamous LACTIC ACID.

Contrary to popular belief, Lactic acid (along with NAD+) is actually the REASON we can continue to work out, not the cause for the burn. We would “burn up” much quicker if it weren’t for lactic acid.

Of course, there is only so much these guys can do as the hydrogen atoms keep pouring out, and eventually things get turned over to the next energy pathway called the Oxidative Pathway. The Oxidative primarily uses fat as an energy source and will fuel you the rest of your exercise (but will be much slower), and is commonly referred to as “aerobic” work, where the ATP-PCr and Glycolitic are “anaerobic”.

Energy Pathways Graph

Beta Alanine

You may have heard me recommend beta alanine along with CREATINE for supplementation pre workout. The reason beta alanine is so useful is because it also acts as a buffer to transport those hydrogen atoms out of the cell, this delays fatigue and allows you to go longer with less “burn”. So in essence beta alanine acts like “lactic acid”.

So there you go! Now you actually have some clue what you’re talking about when it comes to lactic acid… go brag about it! 😛


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