Another article on marathons/ultras being bad for you

Alex Kubacki wrote:

Mr MattM wrote: It seems that it's specifically hard(er) efforts over longer duration that are the issue.

I think that's the crux of it right there. There's a big difference in a long run at marathon pace and a long run at a much slower pace.

If you look at it from an evolutionary biology standpoint, it makes sense. Persistence hunting was about the ability to keep going and going and going until the prey keeled over from exhaustion. Great speed was not required was probably counterproductive. So that's how we're wired today. Most runners nowadays are driven to maximize their speed - but maybe these studies suggest that approach goes against our biology and is pursued at a price.