Some 42.9 million women are living with heart disease. According to the American Heart Association, heart attack is the number one killer of women in the US. You don't need to become a statistic. Just 30 minutes of physical activity a day can reduce the risk of heart disease, the American Heart Association notes, and it is asking women to walk. Walking is the easiest and cheapest form of physical activity. If you're at risk for heart disease, have been diagnosed with it, sufferd a heart attack, are recovering from heart surgery, have a sedentary job, a sedentary lifestyle, or want to be fit,...