Debunking the Myths About Lactic Acid, Fatigue, and Recovery

For decades, lactic acid has taken the blame for several undesirable consequences of hard muscular work. This has included—but has not been limited to—the burning sensation during prolonged contractions, the delayed-onset muscle soreness that ensues following the workout, and even the delay of metabolic recovery.

You can’t watch a football game or read a fitness magazine without hearing about “lactic acid buildup” or “clearing the lactic acid out” the day after a hard workout, or other things along these lines.

Essentially, the fitness industry has been shouting the following:

But we’re here to tell you that this is not the case!

What is Lactic Acid?

First, some semantics: technically we’re talking about lactate in this article. The technical difference between lactic acid and lactate is chemical. Lactate is lactic acid, but missing one proton. To be an acid, a substance must be able to donate a hydrogen ion. When lactic acid donates its proton, it becomes its conjugate base, or lactate. When you’re talking about the body’s lactic acid production or “lactic acid threshold,” the difference is largely a matter of semantics. Regardless, the body produces and uses lactate—not lactic acid.

How Muscles Produce Lactic Acid

Moving on, lactate is a byproduct of anaerobic metabolism (burning glucose).

Glucose, when burned for ATP (energy), produces a substrate called pyruvate, which has the ability to enter the mitochondria and produce even larger amounts of ATP when combined with plenty of oxygen.

Fuel Not Foe? The Role of Lactate in The Body

This is all well and good under normal conditions. However, under intense exercise an athlete can experience a scenario where the pyruvate stacks up faster than it can be processed in the mitochondria. This would be a major problem if it weren’t for our hero, lactate!

Hydrogen ions attach to the pyruvate to form lactate, which can then be repurposed a few different ways.

First, lactate functions as a buffer to keep your pH regulated. The excess pyruvate would make your muscle cell excessively acidic, but the addition of hydrogen ions through the formation of lactate keeps this from happening. Nice.

Lactate can also become a fuel when the Hydrogen ion is removed later on by oxygen. For this purpose, it can even be converted for use in other muscles, in the heart, in the liver, and even in the brain. Incredibly, this means that the lactate produced as a byproduct of intense muscle contractions can be used later on in other parts of the body.

And perhaps most excitingly, lactate can function as a signaling hormone, helping to facilitate many of the desired adaptations from intense exercise. From an athletic performance standpoint, it’s of special interest that lactate can upregulate the activity of glycolytic enzymes that are responsible for the burning of sugar for energy during high-intensity muscular work, improving your fitness and work capacity in the process.

Lactate gets a bad rap, but as you can see, it helps your body run at peak efficiency and has many uses.

Optimizing Your Lactate Production

So how can we make use of this information? If lactate is desirable, how can we make sure we’re getting plenty of it?

Well, since lactate is a product of glycolysis (the burning of sugar in the muscles), and since glycolysis happens primarily in the concentric phase of muscle contraction, the best way to optimize the production of lactate is to pursue the highest-quality concentric contractions that we can.

We’ve written at length about how you’re forced to under-load yourself when you’re lifting weights. This means you’re getting a subpar stimulus in both the concentric and eccentric phases of contraction.

ARX’s Adaptive Resistance, however, allows you to maximize your force production during every single concentric contraction. This, in turn, maximizes the production of lactate in the target muscle group. Over time, this increases your body’s ability to accommodate elevated levels of lactate, and upregulates all of the enzymes involved in muscular work capacity.

This is obviously a huge benefit for both athletic performance and metabolic health, and we’re very pleased that optimizing lactate production is yet another task for which ARX is the best tool available.

The Bottom Line

Far from being a necessary evil or something to be avoided or minimized, lactate—commonly referred to as lactic acid—is a desirable byproduct of high-quality muscular contraction.

It can reduce the acidity in the muscle cells to allow for more work to be done, it can be repurposed as a fuel for the muscles during deep fatigue, and its presence can even function as a molecular signal to facilitate adaptive responses to exercise all over the body.

So don’t be afraid of a little lactate, and enjoy the burn!