Misconceptions about Lactic Acid

Lactic acid has always been thought of as the detriment in exercising: It's buildup will cause soreness in the muscles and limit athletes from exercising continuously.

This theory was challenged by Dr. George A. Brooks, a professor in the department of integrative biology at the University of California, Berkeley. After speaking with coaches who thought differently about what was limiting the body, Dr. Brooks developed new theories on the subject.

Rather than a waste product of the muscles, lactic acid is actually a fuel produced from glucose. A trained athlete is able to absorb more lactic acid and use it for their extensive workouts.

The history of lactic acid came about when a Nobel laureate, Otto Meyerhof, conducted research by placing a frog's bottom half within water. Following muscle contracts from electric shocks, the muscles would stop and lactic acid will be mixed in with the water. Then the notion that the lack of oxygen produces lactic acid, leading to fatigue, came about.

But if this is true, how come muscle soreness continues for days even after all the lactic acid has depleted from the body?

Dr. Brooks continued in his research, despite hardships such as acquiring grants or the accusing criticisms from colleagues. Current understand involves how the muscle will use up glucose or glycogen to produce lactic acid. This lactic acid will then be used by mitochondria as a fuel.

Coaches understood that by exercising, the lactic acid will be consumed faster thus producing more energy. This can be explained through the increasing mitochondria mass through training.

http://www.nytimes.com/2006/05/16/health/nutrition/16run.html?_r=1

Shu Ho
VTPP 434 afternoon section