When the disease process sets in, you are often times too late. It is impossible to prevent a heart attack after you have had one(because you already had one and damage has occurred from it). It is impossible to prevent a stroke if you've already had one(damage has already occurred). The best we can hope to do in these cases is minimize damage and prevent further incidents. That is why we need to start getting healthy in our younger years so our final 10 years look like the gentleman's on the left. Diet, exercise, nutritional help, relaxation are among the key things we need to work on to stay healthy and enjoy the duration of our time on earth.