When it comes to fitness and exercise, there’s no shortage of advice out there. Luckily, there’s Gretchen Reynolds, the Phys Ed columnist for the New York Times. Her job is to cut through the chaff and find out what exercises, regimens and diets actually work, and which are simply hokum. She also wants to show just how little exercise you can do to get lots of health benefits. Reynolds joins us Thursday to bust popular health myths and tell us what it takes to exercise better, train smarter and live longer.