Friday, May 8, 2009

The Lactic Acid Myths

The latest scientific knowledge of lactate metabolism includes the following points:

1) the human body does not produce lactic acid at all, but lactate;
2) lactate does not cause muscular acidosis;
3) muscular acidosis is only a minor cause of muscle fatigue;
4) muscle cell depolarization is a much more potent cause of muscle fatigue during high-intensity exercise;
5) lactate actually delays fatigue caused by muscle cell depolarization;
6) the body can recycle lactate to glucose, the muscles’ primary source of fuel for high-intensity exercise;
7) lactate can be directly oxidized inside cellular mitochondria to yield energy (in other words, far from being a byproduct of anaerobic metabolism, lactate is an aerobic fuel);
8) 75 percent of the lactate produced by the muscles during exercise never leaves the muscle cells but is used directly for energy;
9) lactate production during exercise upregulates genes that generate new mitochondria (in other words, high levels of exposure to lactate during exercise lead to physiological adaptations that strengthen aerobic capacity).

Thanks Matt!
 
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