The Truth About Lactic Acid
Everyone knows that feeling of soreness the day after working out. It is called Delayed Onset Muscle Soreness or DOMS. Due to some outdated research, most people think that lactic acid is to blame for the discomfort. It is also a popular belief that massage can “flush out” the lactic acid and relieve soreness. While massage can help with the soreness and recovery, lactic acid does not reside in your muscles thus it will not be “flushed out”. Let’s talk about the real cause of DOMS and the truth about lactic acid.
Lactate becomes present in the body the more intensely you exercise. Lactate is the base for lactic acid. The body uses one of three metabolic pathways to provide fuel to working muscles. Each of these pathways converts a particular type of fuel into ATP, the high-energy molecule that enables the actual contraction of muscle fibers.
Specifically, the anaerobic pathway is the fastest at providing ATP to working muscles. Its primary fuel source glycogen (stored glucose) is locally available, stored in and around the muscle itself, making its conversion to ATP a quick process. The anaerobic production of ATP is also called glycolysis (breakdown of glucose).
The process of glycolysis results in the formation of lactate and hydrogen. These two molecules disassociate and have different end points in the body. If lactate and hydrogen were to remain a single unit, then it would be lactic acid. It is unlikely that you would ever find any lactic acid in the blood.
Lactate can remain in the muscle cell for energy or leave the cell and travel to active and inactive muscles to be used as a fuel. Thus, as soon as lactic acid is produced by the body, it is disassembles and used up by the liver, within 45 minutes of exercise at most. Lactic acid cannot even really exist in the body because blood pH is too neutral, (around 7) and acids require very low pH.
What causes the the next day? Building muscle and making fitness gains requires the body the push the limits of the muscles capabilities. This causes microscopic tears in the muscle fibers that will be built back stronger than before. So, DOMS is caused by exercise-induced muscle damage. Post-exercise soreness is also triggered by inflammation and the release of chemicals such as histamine, which causes fluid to accumulate, producing swelling and pain.
How can massage help? While massage does not force any acid out of your muscles, it does force nutrient rich, oxygenated blood into the tissue. It also ramps up the lymphatic system enabling it to carry away metabolites to be eliminated from the body. Both of these processes are required to heal properly.
So here is the bare-bone explanation of why lactic acid is not to be blamed for DOMS. Now you cannot ask a massage therapist to “flush out” lactic acid from you muscles but rather seek to enable the body to heal quickly.