Will running kill you, as you always suspected, and as you vocally informed your mom and dad and P.E. coach and personal trainer and random passersby at the gym and the park and on the subway? Yes. Yes it will.
None of the younger athletes or the older nonathletes had fibrosis in their hearts. But half of the older lifelong athletes showed some heart muscle scarring. The affected men were, in each case, those who'd trained the longest and hardest. Spending more years exercising strenuously or completing more marathon or ultramarathon races was, in this study, associated with a greater likelihood of heart damage.
The real shame here is that internet websites that aren't as scientifically sound as we are will twist these scientific findings for a few extra "page views" and blare out sensationalist headlines like "Exercise Will Kill You." Get it straight, America: it's not exercise that'll kill you. Just running. Which sucks big time, anyhow. Plus makes you look all skinny and haggard. Stick to real exercise. Squat harder. Live longer.