I had a heart attack last year whilst swimming and at only 39 despite swimming five times a week and having no obvious underlying issues. It feels profoundly unfair!
No I have zero chronic conditions, no auto-immune disorders that might cause issues with clotting, family history and so on. Basically from a root cause perspective it's unexplained.
So sorry to hear that. Did you experience any warning signs before, like mild chest pains, palpitations, or shortness of breath, that day or in the weeks prior? Also, were you pushing yourself on that day compared to other days of your week, or did it just come out of nowhere at an average pace day?