Cooling down, the gradual slowing of exercise to a full stop, was long thought to flush the lactate from muscles, thus reducing the likelihood of soreness later. But as Gretchen Reynolds writes in the New York Times, there’s a problem with that: lactate doesn’t cause soreness. How then, does cooling down relieve soreness? The short answer is it doesn’t. Reynolds cites a 2007 study, for which people walked backwards for 30 minutes on a treadmill set at an incline to simulate going downhill, an exercise famous for making muscles sore. Some of the backwards walkers warmed up, others cooled down, and some did neither. Two days later, Reynolds reports, those who warmed up had less soreness, and those who cooled down were just as sore and the others. You get the picture. Read more in the New York Times.