The National Walkers' Health Study recently conducted the largest known study about walkers. It was administered to 40,000 different walkers, mostly middle age. Some walkers were slow and some were nearly jogging. Gretchen Reynolds joined us to talk about the findings. Reynolds is a health reporter for the New York Times and author of "The First 20 Minutes: Surprising Science Reveals How We Can Exercise Better, Train Smarter, Live Longer".
Click Read More to hear our interview with Gretchen Reynolds.