The Truth About Lactic Acid
Everything You Thought You Knew About Lactic Acid Is Wrong
Trainers and coaches often point to lactic acid buildup as the cause of muscular fatigue. Problem is, your body doesn’t produce lactic acid. Confused? We set the record straight here.
Ah, lactic acid, the much maligned (and misunderstood) participant in the body’s metabolic energy systems. Many trainers and even some physicians make the same mistake, blaming lactic acid not only for the deep muscle burn felt during exercise and the intense ache afterwards, but also for calling it lactic acid in the first place.
“One of the long-standing myths in exercise science and popular culture is that lactic acid causes fatigue,” explains Lance Dalleck, an assistant professor of exercise and sport science at Western State Colorado University. The only problem is that the body doesn’t produce lactic acid, not even during intense exercise. “Lactic acid exists in sour milk,” says Dalleck, “and blood and sour milk have markedly different mediums.”
Meet the Real Lactic Acid
What most people are referring to when they say “lactic acid” is actually lactate, and it’s not responsible for the burn you feel in your legs after running intervals or peddling furiously to keep up with the peloton in a road race. Nor is it responsible for the soreness you may feel up to 48 hours after a tough workout, as many believe. Indeed, it’s not a waste product of exercise at all. On the contrary, lactate helps to delay fatigue, and can even serve as a fuel for your muscles, says Dalleck.
The whole misunderstanding dates back to a 1922 study by two British scientists, Otto Meyerhoff and Archibald V. Hill. In their Nobel-Prize winning research investigating the energy capabilities of carbohydrate metabolism in skeletal muscle, they suggested that lactic acid is produced in humans as a side reaction to glycolysis (the breakdown of glucose to fuel muscular work). And that’s essentially how it has been explained ever since: Lactic acid is a sort of residue from your muscles burning fuel, and its buildup is what causes the burn and ache athletes commonly experience during and after intense effort. Because after all, acid burns, right?
What recent studies have found fairly conclusively is that while lactic acid—or more accurately, lactate—coincides with “acidosis” in muscles, it’s not the cause. During vigorous exercise, muscles gobble up ATP, the body’s primary energy source. Every time an ATP molecule is split for energy, it breaks down into ADP and one hydrogen ion, also called a proton. It’s the increase in these protons that causes acidification, known as acidosis, and that does burn.
Coinciding with this buildup of protons (from the splitting of ATP) is the buildup of pyruvate molecules, which are produced during the last step of glycolysis. Each pyruvate molecule absorbs two protons to become lactate. Thus lactate production is actually a consequence of acidosis, not the cause, and helps to buffer the negative effects of it. What’s more, during moderate and hard exercise, lactate can even be shuttled back into mitochondria (i.e., the cell’s power plants) and converted into energy. But at some point during intense exercise, the buildup or protons overwhelms the ability of pyruvate to absorb them. That’s when you feel the burn, and that’s when you have to take matters into your own hands.
How Beat the Burn
Your best bet here is beta-alanine, an amino acid that combines with another amino acid called L-histidine to create a substance called carnosine, which buffers against acid buildup in muscle tissue. You’ll find carnosine in beef, but you’d need to eat a whole lot of it to receive an effective dose for improving exercise performance. And since there’s already plenty of L-histadine circulating in your body, supplementing with beta-alanine is the most efficient method for creating performance-enhancing levels of carnosine at the cellular level. (Unabashed product plug: Beta alanine is one of the primary ingredients in Beachbody Performance Energize, our most powerful performance booster to date.)
Because it takes time to elevate carnosine concentration, results typically occur after 1 to 2 months of daily use. The only common side effect from beta-alanine consumption is a harmless, but potentially uncomfortable symptom called paresthesia. It’s characterized by a tingling sensation throughout the body, and most often occurs with high doses. If you experience paresthesia, try taking smaller (i.e., less than 800 mg) doses of beta-alanine throughout the day instead of one large one.
But What about Muscle Soreness?
Along with acidosis, lactate is also frequently blamed for delayed onset muscle soreness (DOMS), which can occur as soon as 6 hours after exercise, and usually peaks 48 hours afterward. The blame is misplaced here as well, as DOMS is caused by micro tears in muscle, not the buildup of lactate. Still, there are several steps you can take to ease the ache.
Pop Some Ibuprofen
The soreness you feel after a tough workout is the result of swelling and inflammation caused by the micro tears mentioned earlier. Popping Ibuprofen, which is an anti-inflammatory, can significantly reduce the pain, according to a study by Greek researchers in the Journal of Strength and Conditioning Research. But that relief may come at a price. An ever-growing body of research has also linked NSAIDs (including ibuprofen) to everything from cardiovascular issues and intestinal dysfunction to suppressed protein synthesis post-exercise. Occasionally taking a couple of capsules is probably just fine—but give some serious thought to using it regularly.
Take Tart Cherry Extract
Doing so can help reduce DOMS not only after a tough endurance workout, but also after intense resistance training, according to two separate studies (available for viewing here and here) at Texas A&M University. Both studies supported the results of previous research, showing that tart cherries can reduce muscle breakdown and inflammation, thereby reducing soreness.
Give Yourself a Massage
Using a foam roller to knead your muscles post-workout can significantly reduce DOMS, according to a recent study in the International Journal of Sports Physical Therapy.Give each major muscle group at least five rolls, starting with your calves and working your way up your body. Spend extra time on sore spots.
Wear Compression Gear
People who wear compression garments after their workout experience less soreness and faster muscle recovery than people who wear a more traditional gym outfit, like a t-shirt and shorts, according to a recent study in the Journal of Sports Science and Medicine. The reason: By compressing the muscle, such garments help reduce swelling and pressure.
By Ben Sullivan