I'm 50 - former D1 runner...still running 60mpw with 2 faster type sessions per week - track or tempo, etc...I have a terrible family history of heart disease.
Ric Sayre's recent death combined with those of others in the past - Brian Maxwell, Andy Palmer, Ron Dawes, motivated me to get screened beyond the normal lipids profile and blood pressure check. EKG was fine...everything else looked very good...lots of questions from the doc etc.
Here's the deal - we all have some level of plaque in our arteries - those who exercise have a much lower chance of a cardiac event - gets lower as the amount of exercise increases...to an extent...then the curve rises...as the amount and intensity of your exercise increases, your chances of an event increase slightly due to the fact that when we hammer, the blood gushes through the arteries - slightly increasing the chance of a plaque disruption, causing a clotting, resulting in an attack. How much hammering is too much? They don't know.
Bottom line, if your lipids and BP are good, you have no chest pain while hammering your workouts, the only thing you can do is take a daily aspirin to lessen the clotting effect if you have a plaque disruption...just thought you'd like to know.