Myocardial infarction, or heart attack, is a term that may show up as a cause of death when there are also other underlying illnesses or injuries. The heart is the last thing to shut down, so to speak, and can thus get "credit" for the death. Bottom line at any age, keep in good condition and health and know your body ... easier for a lot of people now that insurance is required to cover more preventive medicine such as periodic physical exams. Another thing is, turn around when your body is telling you things aren't right. Except under extreme weather conditions, the body is pretty resilient and can generally survive quite a bit.