Lactic Acid
 

Heres a bit of stuff I was looking into regarding lactic acid..

What is Lactic Acid

Lactic acid is a byproduct of the lactic acid system resulting from the incomplete breakdown of glucose (sugar) in the production of energy. The Anaerobic threshold (AT) is when aerobic metabolism no longer supplies all the need for energy, energy is produced anaerobically; indicated by an increase in lactic acid. Also known as lactate threshold.

To produce energy for movement, the muscles primarily use fat and carbohydrate for fuel. When carbohydrates- which are a sugar based fuel source- are broken down, lactic acid is produced in the muscles. As the lactic acid seeps out of the muscle cell and into the blood, hydrogen ions are released and the resulting salt is known as “lactate”. As the intensity of the exercise increases, the amount of lactate also increases. At low levels of production, the body efficiently removes and recycles lactate.

As you exert yourself more, and shift from aerobic to anaerobic (light breathing to heavy breathing) lactate production increases. It increases to the point where the body can’t keep up with its removal. Lactate then begins to accumulate in the blood interfering with energy production and muscular contractions, thus causing fatigue. This type of fatigue occurs more often with high intensity, shorter duration exercise (like sprint triathalon races). The way to improve the body’s ability to remove lactate and your tolerance of it is with short, high-intensity efforts, followed by long recoveries. One side effect of lactic acid immediately after your workout (like a sprint run) is nausea. According to an article in Runners World , you can prevent this feeling by conditioning yourself and becoming more tolerant to lactic acid in your system.

One good way to increase the removal of lactic acid is to cooldown after a workout. It is believed that the stiffness that occurs post workout (Delayed Onset Muscle Soreness (DOMS)) however, is not actually due to lactic acid build up. In fact, whether you cool down or not after a workout, the increased lactic acid that was produced during your workout will be gone within 30-60 minutes. Contrary to what many people believe, lactic acid is not the direct cause of muscle soreness post exercise.

Diet and Lactic Acid
Eating a high-carb, low fat diet causes a greater production of lactic acid by the muscles during exercise, and at rest. This is most likely the result of the body using carbohydrate preferentially for fuel when it is abundantly available, while not burning as much fat. Carbs appear to “turn off” the body’s fat-utilization processes.

j

Yep, lactic acid is the 'burn' you feel that goes away a few minutes after you stop and rest - once you increase oxygen and allow for the citric acid cycle to resume.

DOMS on the otherhand, last a bit longer. It is now generally believed that the pain we call DOMS is caused by free radical damage that occurs when muscle tissue is torn during eccentric contractions. The actual cells lose integrity and are invaded by neutrophils, leukocytes and macrophages - the macrophages actually worsen the situation by releasing cytokines (low-molecular-weight proteins which can function as immune mediators). Because of this inflammatory response there is an increase in fluid volume of the muscle (muscle swelling). It is now believed that inflammatory mediators such as bradykinin, serotonin and histamine throughout this inflammatory response account for a portion of the pain of DOMS.

Damage to the cell wall can increase the intracellular level of calcium and cause degradation to calcium pathways (reducing the ability of the muscle to relax). This perpetuates tissue degeneration and is believed to be responsible for the pain after the first 24 hours.

It has been my experience that when I eat LC and workout I rarely experience lactic acid build up - that burn just isnt there. Then again, neither is very much muscle glycogen. Little glycogen = little glycolosis.

Why lifting LC proves to be less of a DOMS issue is also likely related to glycogen levels. Less glycogen equals less strength, and consequently less lifting of heavy tissue damaging weights.

-Nat