Debunking the Myths: The True Story of Lactic Acid in Running

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Cross Training For Runners
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Written by :

David Dack

Looking for the best ways to manage lactic acid while running? Then you’ve come to the right place.

Here’s the truth.  

We’ve all been there, haven’t we? Pushing through those final miles, teeth gritted, as an unforgiving wave of fiery sensation conquers our muscles.

Common lore would have us believe that lactic acid is the sneaky mischief-maker behind this discomfort. And, like dedicated detectives, athletes and runners from every corner of the globe have committed to hunting down strategies to mitigate this infamous burn. East, west, north, south—you name it, they’ve searched it!

But here’s the truth.

Lactic acid has been accused, tried, and convicted in the court of athletic opinion without a fair trial. Yep, it turns out we might owe lactic acid an apology for labeling it the “bad guy” in our painful post-run pains.

In today’s post, we’ll be diving into the true secrets behind lactic acid and its often-misunderstood role in our athletic endeavors.

If you’ve ever whispered a small curse towards lactic acid (we’ve all done it!), this is the place to uncover the truths, debunk the myths, and perhaps shed light on an unexpected hero in our workout saga!

Ready to leap into this adventure and unearth the mysteries of muscle burn together? Let’s hit the ground running!

What is lactic acid?

Lactic acid isn’t just a random substance your body produces; it’s pivotal for our well-being. It emerges during the breakdown of glucose through a process called glycolysis. Think of glycolysis as your body’s backup generator. When your muscles can’t get enough oxygen (especially during high-intensity exercises like sprinting or heavy weight lifting), glycolysis kicks in, producing ATP energy without oxygen.

Science backs this up.

Research out of the Journal of Physiology found that during high-intensity exercises, our muscles prefer to generate energy through this anaerobic (without oxygen) pathway.

That’s right!

The more you push yourself, the more lactic acid your body churns out.

The Process Of Lactic Acid Production

Have you ever wondered how our bodies keep up with demanding workouts? One word: energy. And a key player in this energy game is lactic acid.

Let’s break down this fascinating process without getting bogged down in the science jargon.

From Dinner Plate to Muscle Power

When you munch on that delicious bowl of pasta, your body gets to work. The carbohydrates you consume are broken down into glucose, ready to fuel your muscles. Through a process called glycolysis, this glucose is transformed into an energy molecule known as adenosine triphosphate (ATP).

Oxygen’s Role

Now, here’s where things get interesting. The amount of ATP produced hinges largely on one factor: oxygen. Simply put, the more oxygen available, the more ATP produced.

High Intensity = Low Oxygen

Imagine you’re running a 100m dash, giving it your all. Your body demands high power in a snap. This task falls on your fast-twitch muscle fibers. But there’s a catch – these fibers aren’t the best at using oxygen.

So, even though your muscles scream for more ATP during these intense moments, there isn’t enough oxygen around to produce it efficiently.

Enter Anaerobic Glycolysis

This is where your body pulls off a clever trick. When oxygen is scarce, it shifts to anaerobic glycolysis. In this process, glucose is not fully broken down in the oxygen-dependent pathways. Instead, it turns into lactate. This shift allows the muscles to keep working, albeit for a short duration.

Additional Resource – Your Guide to Groin Strains While Running

Does Lactic Acid Make Your Muscles Burn When While Running & Exercising?

For years, if you asked anyone why our muscles burn during an intense workout, they’d point the finger at lactic acid. And honestly, it seemed like a convincing culprit. But science, ever-evolving and enlightening, has revealed that the story isn’t so simple.

The Lactic Acid Misconception

Most of us have been there: pushing hard during a workout, and then WHAM, a burning sensation in the muscles that make us want to stop. It was traditionally believed that this discomfort was caused by a buildup of lactic acid. The thinking went something like this: the harder you exercise, the more lactic acid your muscles produce, and this excess lactic acid causes the burn.

But Here’s the Plot Twist

The truth is, lactic acid is not the villain in this tale. In fact, when your body produces lactic acid, it quickly splits into its constituent parts: a lactate ion and a hydrogen ion.

The real mischief maker? Those hydrogen ions.

Let me explain.

Hydrogen Ions Are The Real Villains

Research has turned the tables on the old belief. While lactic acid does play a role in the process, it’s not the direct cause of the burn. When we exercise, our bodies produce lactate, which splits into lactate ions and hydrogen ions. As the intensity of the exercise grows, these hydrogen ions accumulate faster than our body can eliminate them. This excess of hydrogen ions makes the cellular environment more acidic, and voila!

That’s the familiar burning sensation you feel during a particularly grueling set of squats or that final sprint.

Lactic Acid’s Brief Existence

Here’s an interesting tidbit: technically speaking, lactic acid doesn’t really ‘hang out’ in our bodies. The moment it’s produced, it splits due to the alkaline environment of our blood. Our blood’s pH, which usually stays between 7.35 and 7.45, is not acidic enough to maintain lactic acid in its complete form.

Don’t take my word for it.

Lactic acid is created when a hydron atom bonds with the lactate molecule. It’s specifically a blend of a positive hydrogen ion and a negative lactate ion. However, researchers have discovered that lactic acid as a molecule cannot exist in the body in its complete form since the pH of the human body is too high.

Additional resource – Here’s how much water a runner should drink

But what about post-exercise muscle soreness?

Delayed Onset Muscle Soreness, or DOMS for short, is the kind of muscle soreness that sets in a day or so after exercise. It’s different from the acute type of soreness you feel during or immediately after a workout.

Why Does DOMS Happen?

There are several theories about what causes DOMS, but the most widely accepted explanation is the one related to muscle microtrauma:

When we push we muscles harder than usual, it results in tiny tears in the muscle fibers. This microdamage triggers inflammation as the body tries to repair and protect the area. Inflammation, in turn, leads to swelling and soreness.

Eccentric exercises, or the lengthening phase of a movement (like when you’re lowering a weight during a bicep curl or going downhill while running), can cause more significant muscle damage, leading to more pronounced DOMS. That’s why if you incorporate a new exercise with lots of eccentric action, you might find yourself wincing when you sit down or climb stairs the next day!

Additional resource – Running with a labral tear


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