Doctors say exercise doesn't have to involve high-octane workouts or expensive gym memberships. Walking more, taking the stairs and making an effort to carry your groceries, laundry or garbage will keep you strong. Elmer Easton, who will be 102 in December, has taken a walk every day of his retirement, weather permitting. In a recent survey of centenarians by health-care provider Evercare, 41% said they still take walks to keep up their stamina. More From Forbes: America’s Healthiest Cities World’s Most Dangerous Places to Breathe The ‘Healthy’ Choices That Are Costing You The opinions expressed are solely those of the author and do not necessarily reflect the views of Comcast.