Friday, May 19, 2006

Lactic Acid Is Your Friend?

A friend sent me two links to articles describing recent research suggesting that lactic acid, the much-aligned molecule among athletes, is actually used as fuel by the muscle cells. Previously, it was preached that at a certain point, the "lactate threhold," the body started producing too much lactic acid, resulting in a significant decline in athletic performance. To quote the Berkeley article, this research suggests that
  • muscle cells use carbohydrates anaerobically for energy, producing lactate as a byproduct, but then burn the lactate with oxygen to create far more energy. The first process, called the glycolytic pathway, dominates during normal exertion, and the lactate seeps out of the muscle cells into the blood to be used elsewhere. During intense exercise, however, the second ramps up to oxidatively remove the rapidly accumulating lactate and create more energy.
  • Training helps people get rid of the lactic acid before it can build to the point where it causes muscle fatigue, and at the cellular level, Brooks said, training means growing the mitochondria in muscle cells. The mitochondria - often called the powerhouse of the cell - is where lactate is burned for energy.
I think these are interesting articles because there has been so much hype about "lactic acid thresholds" and there are even tests that supposedly measure this level. It appears that what we may actually be measuring is muscle cell mitochondrial density.

The links are:
Berkeley Article
New York Times Article

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