A recent study of 100 marathon and ultramarathon runners aged 35-50 found that almost half had precancerous polyps, with 15% having those at high cancer risk. The researchers are puzzled by the results, given that most participants were young, lean, and active.
The study’s lead author wants to know: could extreme running contribute to colon cancer? Two of the runners had completed multiple 100-mile ultramarathons, while another finished 13 half-marathons in a year. Yet all three developed advanced colon cancer by age 40 without any known risk factors.
To get answers, Dr. Timothy Cannon conducted a study with 100 participants, who underwent colonoscopies. The results showed an alarming rate of polyps and adenomas, much higher than the general population’s rates. While not yet published, this study suggests that extreme running may be linked to increased colon cancer risk.
Source: https://www.nytimes.com/2025/08/19/health/running-colon-cancer.html