Under the brilliant headline "The latest obstacle in obstacle racing is bloody diarrhea," the Washington Post reports that the growing trend of competitive obstacle course running—now practiced by 1.5 million people—comes with a growing trend of falling in the mud and catching a mouthful of animal feces.

The CDC found Thursday that 22 racers who got sick after a 2012 Tough Mudder race had swallowed mud laced with cattle or swine feces and become infected with Campylobacter coli. This common bacteria can bring on a week of diarrhea, cramping, abdominal pain and fever.

And that's on top of the physical pain of running a mud race in the first place. As the Post's T. Rees Shapiro points out, that pain and threat of injury are part of the sales pitch for events like these.

But if you're willing to put up with risks like drowning, heart attacks and paralysis, a little bloody diarrhea shouldn't keep you away. Doctors say it clears up in about a week, so quickly that it's not even worth administering antibiotics.

[Photo: Getty Images]