You'll ruin your knees!
"You now have the opportunity to help inform the debate with your in-laws about the impact of all your running."
Here is the link... http://www.sacramentorunning.com/2011/11/14/ultra-study/#more-1977
""...the truth that someday, you will go for your last run. But not today—today you got to run." - Matt Crownover (after Western States)