(New York Times) – A small, preliminary study found that marathoners were much more likely to have precancerous growths. Experts aren’t sure why.

By the time they came to see Dr. Timothy Cannon, all three had advanced colon cancer. He was mystified; the oldest of them was 40, and none had any known risk factors. The doctor couldn’t help wondering if extreme running might have played a role.

So Dr. Cannon, an oncologist with Inova Schar Cancer in Fairfax, Va., launched a study, recruiting 100 marathon and ultramarathon runners aged 35 to 50 to undergo a colonoscopy.

The results were staggering. Almost half the participants had polyps, and 15 percent had advanced adenomas likely to become cancerous. (Read More)