Because a marathon is just not hard-core enough.
Most interesting medical event of the weekend: Twenty-something male runner complaining of abdominal pain radiating sub-sternal.*
After sufficient discussions, a Hx of a defective pyloric valve, possible celiac disease, and oh yeah, this exact kind of discomfort from time to time whenever he inadvertently eats wheat, any potentially alarming element was quelled.
* Chief complaint -- feet hurt. Ya think?
Lotta that going around.