PAWLEYS ISLAND, S.C. -- Walking is the real miracle drug.Scientists have long connected systematic exercise to better health. According to the Centers for Disease Control and Prevention, regular walkers "live longer and have a lower risk for heart disease, stroke, Type 2 diabetes, depression and some cancers."A recent New York Times headline proclaimed, "To Age Well, Walk." The story reported on a massive new study that concluded: "Regular exercise, including walking, significantly reduces the chance that a frail older person will become physically disabled."This is certainly good news for those of us whose age at our last birthday started with a 7.