Superheating the body helps to soften the collagen around the joints. "Collagen is a lot like plastic, & its rigidity eases when you warm it," says Marc Darrow, M.D., director of the Los Angeles based Joint Rehabilitation & Sports Medical Center . "Some athletes ride an exercise bike before stretching, which heats the muscles & softens collagen, but there's no reason you can't do the same thing by adjusting the thermostat," says Dr. Darrow, who includes Kansas City Chiefs wide receiver, Johnnie Morton, among his patients.

Heat also helps "feed" the muscles by increasing the circulation of oxygen-laden red blood cells, says Lewis Maharam, Pres. of the Greater New York Regional Chapter of the American College of Sports Medicine. It's like working a bellow, as you pump more oxygen into your muscles, they are able to burn more fuel & the best way to let that rich, oxygenated blood into the inner recesses of your muscle tissue is to stretch. "Heat speeds up your metabolism," he explains, "& the yoga postures will certainly assist by improving your circulation & elasticity."

But who says our muscles need more oxygen? Speed skaters for one. According to a study published in Medicine & Science in Sports & Exercise, Olympic speed skaters are especially prone to muscle fatigue because of the tight crouch they skate in decreases blood flow to their calves & thighs. Something similar happens to you & me when we're hunched over a computer or cramped behind the wheel of a car. "Some of your muscles are so oxygen-starved, they're living on dogma," Pier quips. "They've heard about red blood cells, but never actually seen them."