The Lactic Acid Myths

So I’ve got some good news and some bad news. Bad news first because it’s always better to end on a good note. The bad news is that the human body doesn’t produce lactic acid. That’s right, when we used to say “OMG the lactic acid build up was insane my legs were burning like crazy!” we were all making up a bunch of misguided misinformed BS. It’s cool. I did it too. GOOD NEWS:  There is something that does build up in the muscles related to lactic acid that the human body does produce called L-Lactate.  It’s very closely related but is a salt formation.

Lactate is produced from Pyruvate, and pyruvate in turn is kind of a meeting place in multiple metabolic pathways. It can be converted to fatty acids and stored as energy, it can be turned into carbohydrates by enzymes and stored in the muscles or used to replenish liver glycogen, or (and this one is REALLY important) pyruvate is an absolute necessity in the Kreb’s cycle. Kreb’s cycle (also called the citric acid cycle) which occurs in the Mitochondria and is primarily responsible for the production of GTP (Guanosine-5′-triphosphate) and then to my favorite molecule – ATP (adenosine-triphosphate).

Kreb’s Cycle

This is the 4^th metabolic pathway that was discovered not very long ago. Sorry for the quick science lesson but this stuff is muy im Kreb’s Cycleportante! So we know that our bodies produce L-lactate, and it is also used for energy production and can refill glycogen stores in the liver and muscles, but why does it cause a burning sensation? Is it causing our bodies to be “acidic”? When we exercise the amount of lactate in our muscles raises to 10 times a normal level, and it can be removed at a rate depending on how oxygenated the muscles are, or other more complex factors. However this is not the cause of that burning sensation.  When energy demands are high, such as in Tabata squats (we all know that burning pain) the ATP requirement from the muscles is extremely high, so high in fact that the rate of production from respiratory reactions (those requiring oxygen) can’t keep up and the body defaults to anaerobic ATP production so that much more ATP can be produced and utilized more quickly. When this anaerobic creation of ATP begins, is when lactate is created. When ATP is used, it is ‘hydrolysed’ which means a hydrogen ion is released. These hydrogen ions lower the pH of the blood (and it is localized to the area of energy usage) we get a burning sensation. Since L-lactate (not lactic acid) levels rise at the same time the hydrogen ions do,  it was assumed that the Lactate in our bodies were the culprit since lactate is closely related to Lactic Acid, but whoops scientists were wrong.  Ohh well we all get to make a few mistakes

As our bodies adapt they store more energy storage in the muscles, and the oxygen delivery system of our cardiovascular system becomes more efficient at delivering oxygen to areas, and furthermore, the body becomes more efficient at handling the amount of hydrogen ions before the “acid buffer” in our muscles is overcome.

Chris ffeelin the burn!

Conclusion:

• When pyruvate cannot be converted to ATP via a metabolic pathway involving oxygen, it defaults to anaerobic pathways, and lactate is produced along with hydrogen ions.
• Lactate is then transferred into the cells and converted to either ATP, glycogen, water, or glucose.
• This is unconfirmed: but I read that up to 50% of lactate that is created during intense exercise is utilized straight as ATP
• Hydrogen ions are the culprit in the acidic burning feeling we get and if levels increase to a high enough density, exercise literally can not continue.
• The buffers in the muscle can be increased by… you guessed it… high intensity exercise.

P.S. Wireless Internet in airplanes is the coolest thing since sliced bread.

2/5/10 : WOD

21-15-9
Push Press or Jerk
Overhead Squat

Optional:
Press 2-2-2 85%
Sumo Deadlift High Pull 5-5-5 60%
Pull-up max rep x 3