The study looked at 88,140 American adults, who were all between 40 and 85 years to begin with. Every participant was asked to report what kind of physical activity they did, and for how many minutes per day or week, as part of the National Health Interview Survey. Minutes running or cycling or participating in some kind of competitive sport (among many others) were all classified as vigorous activity time, while everything from a brisk walk to dancing or gardening was deemed light or moderate physical activity. Then the researchers followed those people for 12 years, through 2009, to see what happened to them. How many died of cancer? How many of heart disease? How many were still alive?