Login | January 07, 2025
Fitness mythbuster 5.0
PETE GLADDEN
Pete’s World
Published: January 6, 2025
Ready for another edition of the fitness mythbuster?
Today’s fitness myth is one that’s more of a misunderstanding and/or misspeaking, and it revolves around two funky little organic molecules crucial to energy production in our bodies.
I’m talking about lactate and lactic acid, which are very commonly spoken of as if they were one and the same thing.
Yet fact is that they are two very different molecules, which despite their one key similarity - aiding in energy production - they perform quite different physiological tasks.
Busting this myth involves taking a quick step into the classroom with a little exercise physiology 101.
So here we go.
Now to begin with both lactic acid and lactate are produced when carbohydrates are broken down.
Lactate, the so-called good guy of the two molecules, is a product of aerobic respiration (with oxygen), and it plays a role in energy production during prolonged exercise, otherwise known as aerobic exercise.
But lactate also plays a role in energy production during quick, intense athletic efforts like sprinting, otherwise known as anaerobic exercise.
Lactate can be found in muscle, blood and some of the body’s other tissues, and its three primary functions are: As a precursor to producing glucose, as a mitochondrial energy source and as a signaling molecule to warn the body about physiological stressors.
Lactic acid on the other hand, often viewed as the bad guy of the two, is a product of anaerobic respiration (without oxygen) and like lactate it’s also involved in both aerobic and anaerobic energy production.
Now when viewed at the molecular level, lactic acid is simply a lactate molecule which has gained an H+ atom.
And this is a reversible reaction such that when the oxygen supply is increased that lactic acid molecule can loose the H+ atom and revert back to a lactate molecule, which is all pretty darned complicated and very confusing to understand if you’re not an exercise scientist (and I’m definitely not), but wow, what a wild duet these two molecules are in the micro world of bio energy production.
Now as I said, lactic acid unfortunately has that bad guy reputation because it immediately conjures up thoughts of pain and suffering.
But in reality, lactic acid has a slew of good, redeeming qualities.
For one and as mentioned, it provides energy to cells when there’s not enough oxygen.
Second, the liver and kidneys can filter it out of the bloodstream to create more glucose for future use.
And three, once out of the cells and back into the bloodstream it can loose that H+ atom and revert back to lactate, thereby enabling more energy to be produced for continued physical efforts.
Okay, so despite the fact that lactic acid can be used in energy production, its primary function resides in its critical role in acid-base balance - pH.
Indeed, and when exercise intensity has reached a point - called lactate threshold - to where lactic acid is accumulating faster than it can be cleared, the lactic acid causes a tightening of the muscles, fatigue, and that all too familiar burning sensation in the muscles, a sensation we’ve all felt at one time or another in our lives.
Now in a sense lactic acid is performing in a “good guy” way because it’s not permitting the muscles to go so far in an intense effort that they’ll end up injuring themselves.
It’s basically making them shut down.
Bottom line, lactate and lactic acid are indeed closely related molecules in that they’re both produced during anaerobic metabolism, and thus they each play critical roles with respect to energy production and physiological regulating.
But when it comes to lactate and lactic acid being used interchangeably in fitness conversations, well, as you can see they’re definitely not the same compound.
Understanding the differences between these two compounds can give you a much better insight as to the intricacies of energy production and how they each impact your exercise sessions in their own unique ways.
So the next time you hear lactate and lactic acid being definitionally abused as if they’re replacements in the old show-tune line, “You say tomato-I say temahto,” you can smile to yourself knowing full well that in this case there really is a big difference.