If lactic acid is not the villian for muscle burn then what is? To understand muscle fatigue, you must understand the pH scale which tells you how acidic or alkaline (basic) the body is on a scale of 1-14. It is based on numbers of hydrogen ions, with pH readings of less than 7 being acidic (more hydrogen ions) and readings greater than 7 being basic (less hydrogen ions).
The human body is slightly alkaline with a pH of 7.4. If you perform an all out sprint your muscles and body will become more acidic with a major drop in pH to about 6.5. A burning feeling sets in the working muscles which become fatigued and eventually unable to contract.
Since LA isn't responsible for the drop in pH from sprinting what is? The answer lies in the fuel sources we use during high intensity activities-carbohydrates in the form of glucose and glycogen (glycogen is stored in the muscle and glucose is already floating around in the blood stream). When glycogen and glucose are broken down for use as energy, they release hydrogen ions. This rapid release of hydrogen ions drastically lowers pH, causing the burning and fatigue associated with exercising in an acidic environment. In summary, it's the hydrogen ion production and increased acidity that cause muscle fatigue, not LA.
LA is actually a hero.It has been found to assist in removing the hydrogen ions from the working muscle cells which helps buffer the acidic environment, bringing the muscle cell back to it's normal pH. After close to 90 years, the villian reputation of LA has finally been put to rest.
--
Dr. Lanny Schaffer is an Exercise Physiologist and the President of The International Fitness Academy. For more cutting edge training information go to http://www.aerobic-exercise-coach.com