A new study of over 1 million people finds that doing at least one hour of physical activity per day, such as brisk walking or cycling for pleasure, may eliminate the increased risk of death associated with sitting for 8h a day.Physical inactivity is linked to an increased risk of heart disease, diabetes and some cancers and is associated with more than 5 million deaths per year and, as the first global economic analysis of physical inactivity shows, costs the world economy over US$67.5 billion per year in health care costs and lost productivity.