If you haven't yet done so, click through to Ultrarunner Podcast and check out the latest interview with Andy Jones Wilkins:
AJW is one of the top masters ultrarunners in the nation. He races - a lot - has numerous wins, and here's the big one...has never DNFed.
Here's what I find most amazing about the guy. He has completely normalized puking as part of the ultra experience. I'm sort of an iron gut and never blow cookies, but AJW sees it as part of the racing action.
Don't believe me? Check out this "interview" at the Leadville 100. Enjoy.