We’re used to thinking of long-distance runners as the embodiment of health: lean warriors soaking head to toe in endorphins as they run 100-mile trails for fun, their heart rates so low they could be mistaken for corpses. A recent study, however, is flipping that narrative: the most intense runners among us might be more prone to colon cancer.

It all started when Dr. Timothy Cannon, an oncologist at Inova Schar Cancer Institute, noticed something off. Three of his patients, all under 40, were super-fit endurance athletes. They didn’t drink. They didn’t smoke. One was vegan. Yet all had advanced colon cancer, and none of the usual risk factors. So, he turned this mystery into a research study.

In the study, highlighted by The New York Times, Cannon recruited 100 distance runners aged 35

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