Ellen and other fitness fanatics will probably be interested in this ABCnews article on the real purpose of lactic acid:

But people like [George Brooks, a biologist at the University of California] have since shown that lactate from lactic acid is a valuable fuel derived as the body breaks down carbohydrates. Not only do muscles consume it eagerly, the brain and heart also suck it up from the bloodstream to keep systems running. High levels of the stuff can cause some sensation of muscle burn during exercise (thanks to the hydrogen ions that are released when lactic acid is broken down into lactate), but it doesn't stick around long after activity.

And now, new research shows that lactic acid serves as more than a fuel.

We'll see if the article holds up under the scrutiny of my resident personal fitness expert.