Lactic Acid: What It Is & How It Affects You

Whether you like it or not, as a runner, you find yourself knee deep in science lessons constantly. Between ever-changing nutritional needs and seeking to advance yourself physically through speed, increased energy or strength, it all boils down to understanding science. It turns out that when the science relates to personal items or interests its way more interesting than your high school biology or health class. And it turns out you get a little bit of a chemistry lesson as well.

You need to know about the sugars (glucose, fructose, galactose oh my!) your body needs for fuel, you learn about the hormones and other items your body releases during a run and all of the sudden it becomes reminiscent of junior year all over again.

One thing that your body releases during exercise, and runners are all too familiar with, is lactic acid. A very basic understanding of lactic acid lets you know you don’t want it to build up in your legs and that you can always blame “the wall” on it. Lactic acid isn’t just something you deal with in a marathon or any long or intense run requiring a lot of your energy could induce the production. What is lactic acid and how does it affect you as a runner?

What is Lactic Acid?

On occasion, when you are exercising for long and intense periods of time your circulatory system can no longer produce enough oxygen for your muscles. To supply energy, muscles shift from an oxygen-based metabolic state (aerobic) to non-oxygen seeking metabolic state (anaerobic). This is also commonly called the lactic threshold or the anaerobic threshold.

Muscles in the anaerobic state break down carbohydrates instead of oxygen to provide energy and this results in something called pyruvate. When your body is working anaerobically pyruvate is transformed into lactic acid assuming that there is no down-shift in exertion level. The pyruvate is then broken down into lactate or what is commonly called lactic acid. Lactate then releases part of a hydrogen atom called an ion.

Lactate is then cleared from your body as it is used by your body as energy. This is against all widely held beliefs and knowledge on lactic acid. Lactate is actually fuel for your body, not waste and can help delay fatigue. If not utilized by your body lactate will build up in your system. Yet,  the build-up people encounter is not from lactate. The acid buildup in your tissue is caused by the hydrogen ions.

Preventing Lactic Acid

One of the main goals of all endurance athletes is to raise their lactate threshold through training. Hence the primary reason for long runs to build aerobic capacity by teaching your body efficient oxygenation of the muscles, the heart, and lungs. In essence, teach efficiency to delay the lactate threshold.

There is also the belief that our best bet is to help avoid the acid buildup is to ingest a natural combination of multiple amino acids called carnosine, which acts as a buffer against hydrogen ion buildup in muscle. This is most often occurring in beef but you need to eat a lot of beef and most of the amino acids that make up carnosine occur in your body in a healthy supply. However, a beta-alanine amino supplement could help.

Clearing Lactic Acid

Almost all lactate produced during a run is cleared within half an hour to an hour after stopping. Active recovery will help clear lactate more quickly. An active recovery would be a slow jog, walking or easy biking. Truth be told, vegging on the couch isn’t going to cause any harm or a massive buildup to occur either.

And contrary to popular belief, a massage isn’t going to bust up that acid any quicker either, but it doesn’t hurt to tell your significant other it will or blame this month’s Massage Envy bill on lactic acid. This also means that those leg drains runners have been doing for years to remove lactic acid from the legs do nothing but make it more difficult to drink your post-run cup of Joe. Same goes for foam rolling; while it has great benefits related to delayed onset muscle soreness (DOMS), you aren’t rolling to move, remove or break down lactate or its acid.

Lactic Acid Lies

Lactic acid is not the cause of immediate or delayed muscle soreness since even when the lactate your body produces is not used, lactate and its acid is cleared from your body quite quickly even when left to your body’s own devices. It, the lactate portion, does not cause fatigue or the “burn” that is often associated with lactic acid.

There have also been some thoughts that breastfeeding‘s first production of milk post-exercise has lactic acid in it or that tastes sour. This is not the case with moderate or up to 75% intensity effort. For the milk to be affected woman would have to endure exercise at almost 100% effort for a duration of time and even then studies are inconclusive on if breast milk is affected; what they are conclusive on is there would be no harm to the baby.

Science teachers should really rethink their curriculum to include helpful tidbits like “Lactic Acid 101” and “Beer Metabolism” it would make for some more interested students and better grades. The truth is to be the best runner you can be, delving into the science to find out why your body does what it does is the secret of good athletes.  Harness your knowledge to make yourself a faster and better runner.  As most coaches will tell you, “Work smarter, not harder.”