Stress is the primary culprit. It usually raises blood ressure, and extreme stress the most. That can cause tiny damage points, or bigger ones, on the inner walls of arteries. Without damage points, LDL can be in higher than preferred concentrations, but stay unharmful. If one s diet is at all low in anti-oxidants, which are most concentrated in red and blue fruits, berries, plums, pomegranates and green teas, then some of the LDL can become oxidized. For some reason I can t recall, the immune cells that attach to the exposed, damaged interior of artery walls then slowly pulls in the oxidized LDL particles. This expands these cells, splits the artery wall further, and evenrually may break loos or partly break off and swing across the artery and block it. Voila ! You have a heart attack. Some people exercise too hard, and that also can raise blood pressure excessively mimicking stress, or they get breathing too hard putting them in oxygen debt and leaving too much CO2 in the blood. CO2 is also an artery irritant, just like cigarette smoke. Its possible his diet is not quite as good as he thought. I thought I was healthy too, and needed an emergency triple bypass almost 4 years ago. I eat a whole lot healthier now than I did then, and exercise wth a a lot more restraint. I hope the heart attacks were small, and he recovers well. If he needs rehab advice, I d be happy to share.