The Truth About Lactic Acid and Your Muscles After Exercise

You hit the gym or workout class hard this morning. By the next afternoon, you feel your muscles screaming at you. Your first thought might be to get home and foam roll to relieve your muscles of all that lactic acid buildup.

While foam rolling would certainly be beneficial, you aren’t exactly alleviating a buildup of lactic acid. In fact, lactic acid has nothing to do with delayed-onset muscle soreness (DOMS). Lactic acid is only one part of a chain of events that take place during and after exercise.

ENERGY PRODUCTION DURING EXERCISE

The body uses two forms of energy production during exercise. In the beginning, your body uses aerobic metabolism to convert oxygen into energy. But as oxygen stores are depleted, your body turns to anaerobic metabolism in which pyruvate is converted to lactate (or lactic acid) to promote glucose breakdown. 

This second form of energy production can only be used for about one to three minutesbefore the body signals that it’s time to stop. Production slows down, and you feel “the burn.” At this point, the buildup of lactic acid creates an acidic environment which prompts you to stop, rest, and breathe as your body switches back to aerobic metabolism.

This buildup and burning mechanism allow our bodies to keep from overworking. It’s a protective mechanism. But once you stop, your body immediately moves back towards the first form of energy production. Any remaining lactate is converted back to pyruvate. Lactic acid doesn’t just hang out in your muscles for 24 or more hours.

These forms of energy production help to guide the use of our muscles. But researchshows that there’s little correlation between lactic acid and delayed-onset muscle soreness (DOMS).

WHY DOMS?

DOMS is a form of muscle tenderness that occurs between 24 and 72 hours after working out. Researchers and fitness experts have many theories as to why DOMS occurs, but none of them have been proven yet. Some believe that the soreness is caused by the buildup of various metabolites in the tissue that are elevated post workout.

Along the same vein, some believe that rhabdomyolysis sets in, which occurs when high levels of muscle injury provoke the release of damaged protein directly into the bloodstream. This cell damage is a common theory you’ll hear in the fitness community. Some call it “microtrauma.”

Microtrauma is the idea that your muscle fibers were damaged during exercise. The damage to the tissue triggers an inflammatory response, and that inflammation causes your muscles to swell and become sore.

WHAT TO DO ABOUT DOMS

Evidence regarding treatment for the soreness varies. Some people like to try massage or ibuprofen. While others swear by heat and curcumin.

A counterintuitive approach is to work out. Don’t let muscle soreness stop you from exercise. More exercise can allow blood to flow to the tissue to help in supposed repair. In addition, exercise after a first severe experience of DOMS creates a new threshold, which means you’ll experience less DOMS the more you exercise.