The very sad 58 ear old death is fairly meaningless as a lesson without the detail. Was it an MI, arythmia or what?
If an MI, it could have been the case that regular hard exercise prevented him dying at 48. If an arythmia it could like Fabrice M be dangerous.
If you’ve spent a lifetime at some sort of exercise you’ll know your heart/body. If you’re starting out after a long layoff then see your GP.