Narrator: This is Science Today. If you work out a lot, you're not doubt familiar with feeling the burn of lactic acid. Many consider lactic acid to be a waste product that builds up in the muscles, leading to fatigue, reduced performance and pain. But exercise physiologist George Brooks of the University of California , Berkeley , says lactic acid is not an athlete's poison – in fact, it's a friend in the form of fuel.
Brooks: Lactic acid can also be used to make blood glucose. So, for that to happen, the lactic acid has to leave the muscle, go through the circulation, reach the liver and kidneys to be made into glucose. So, nature has found a way to fuel different body parts by this stuff, which is called lactic acid.
Narrator: In a recent study, Brooks and his colleagues for the first time linked two metabolic cycles – the oxygen-based aerobic, or oxidative metabolism and the oxygen-free anaerobic, or glycolytic metabolism.
Brooks: Lactic acid is really the vehicle which links glycolytic metabolism and oxidative metabolism.
Narrator: For Science Today, I'm Larissa Branin .