. What Is Lactic Acid?
Lactic Acid is a colourless compound produced by almost all tissues in the human body, necessary for the body to function daily. Lactic acid is produced and circulates through your bloodstream all the time, albeit in small amounts. Lactic acid, like Creatine, can also be produced synthetically, for use in biodegradable polylactic acid products (PLA). Although, why you'd want to supplement with Lactic Acid is anyone's guess.
Lactic acid is usually formed by fermentation of glucose, a carbohydrate, by a process called glycolysis. This is a chemical process in which glucose is broken down to pyruvic acid, and carbon dioxide, water, and energy (ATP) are released. If there is an excess of pyruvic acid, lactic acid is then formed.
However, this is a reversible reaction. When the Lactic acid receives oxygen, it is converted back to pyruvic acid, for later use by the body. The lactic acid is carried by the blood from the cramped muscles to the liver where it converted back to pyruvic acid, and then to carbon dioxide, water and ATP. Hooray for science.
Lactic acid is a by-product, produced by the body's tissues, primarily muscle, in order to obtain energy by metabolising glucose in the absence of oxygen. The glucose is either supplied from the blood stream or from it's stored form, glycogen, in the muscles. This is called anaerobic respiration (without oxygen).
Lactic acid (in large amounts) is usually formed during strenuous exercise, and a large amount of lactic acid in muscle leads to fatigue and can cause muscle cramps.
Lactic acid also causes the souring of milk, by fermentation of lactose. This makes Lactic acid useful commercially, as it is used in preparing cheese, sauerkraut, soft drinks, and various other food products.
2. Lactic Acid and Weight Training
When you train hard, you usually get that burning sensation in the muscles that you're working. This "burn" is caused by an excess of Lactic acid in those muscles.
If you are exercising past the point where you cannot provide a sufficient supple of oxygen to the working muscles, lactic acid will accumulate in the working muscles and the blood stream.
Bear in mind when training to failure that muscle failure cannot be achieved without feeling a burning sensation, and you are not pushing yourself to muscle failure if so. This is called training at a Sub-Lactic acid level.
At a Lactic acid level this means that you are feeling a strong lactic acid build-up, or burn in the working muscles on your last two repetitions.
You should struggle on your last two repetitions. This is why so many personal trainers say "Feel the burn!" Although if said trainers do repeat this ad nausem to you whilst you are on your last rep of bench pressing 300lbs, you have my full permission to beat them up. Unless they're bigger than you, of course.
Occasional training to failure actually improves aerobic conditioning. Intense exercise that produces lactic acid raises muscular endurance quicker than moderate exercise alone, because as you improve with training, the now fitter muscles process the lactic acid quicker, therefore the less often you experience the burn. Ya see?
The best way to get rid of the lactic acid in your cramped muscles is to keep exercising at a slower pace. Lactic acid is removed more quickly during walking than during complete rest, as you are keeping your blood flow steady and constant.
So, cooling down allows the blood to continue to flow through the muscles, allowing the lactic acid to be carried to the liver to be converted back to pyruvic acid.
Adequate rest should be taken between heavy sets, just enough so that you can supply oxygen to your muscles to reduce the lactic acid buildup. If you don't, the large lactic acid buildup will make you feel tired and nauseous after your workout.
So, to conclude, periodically going for "the burn" is a good thing, but just remember to rest between heavy sets, breathe deep, and to cool down adequately after any strenuous training.
