Lifting, or elevating, your legs higher than your heart after exercise feels good and helps promote improved lower-body blood circulation. It does not, however, help remove lactic acid from your legs, and lactic acid removal should not be your goal. Contrary to a long-held and popular belief, while the buildup of lactic acid causes your muscles to burn during intense exercise, it isn't responsible for you having sore muscles in the days after a challenging workout.
The myth about lactic acid buildup causing muscle soreness started with a frog. In the early 1900s, Nobel Prize winner Otto Meyerhof cut a frog in half and put the bottom half in a jar without air. He zapped the legs in the jar with electricity to make them move and, when they stopped, he examined the legs and found them loaded with lactic acid. Thus was born, according to "The New York Times," the idea that, without oxygen, lactic acid built up in muscles and caused them to tire.
New Theory
Meyerhof's finding is "one of the classic mistakes in the history of science," according to Dr. George A. Brooks at the department of integrative biology at the University of California, Berkeley. Lactic acid builds up in the legs during running and other exercise, causing a burning sensation that forces you to slow down or stop exercising before you harm your muscles, says Stephen M. Roth, a professor of kinesiology at the University of Maryland. It takes about an hour for lactic acid to be flushed from your body, according to author and track coach Brian MacKenzie.
Cool Down
If you wish to quicken the removal of lactic acid from your legs after a hard run, MacKenzie offers a different recommendation than lifting your legs. He advises you actively cool down after a tough workout. Specifically, he suggests that you engage in a cool-down that provides a "rapid and continuous supply of oxygen to the muscles."
Active Recovery
Active recovery, as opposed to passively laying on your back with your legs raised or even getting a massage, is much more effective in reducing lactic acid in your muscles. Examples of active recovery, MacKenzie says, include walking, light bicycle riding or easy jogging — any exercise that increases blood flow and oxygen delivery to your muscles without harming them or causing further exertion or damage.
