I had a friend who died in his 30s while out running. I forget the term right now for the type of coronary event that he had. He dropped over dead and fell into the ditch by the side of the road. He wasn’t found until the next day.
But even if he had been running down the halls of a hospital, a team of doctors probably couldn’t have saved him. His dad never exercised and also died young from the same type of coronary event. We were told that it was caused by a genetic defect that could have been corrected if the right specialist had looked for it. He thought that running would keep him safe, but given his family history... this is one case where preventative care would habe been a better idea.
Probably aortic dissection, like John Ritter. Once the aorta tears, it’s over.