Marathon runners can run a higher risk of cancer, suggests study
New Study Finds Long Distance Running May Increase Risk of Colon Cancer
Long distance running, such as marathons and ultramarathons, has long been viewed as a healthy activity. However, a new study from Virginia suggests that it may not always be the health boon we thought it was. According to Dr. Timothy Cannon of the Inova Schar Cancer Institute, intense endurance training can potentially increase the risk of colon cancer.
The study, which was presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in 2025, focused on runners who had completed at least five marathons or two ultramarathons. Participants between the ages of 35 and 50 were included in the study, with a specific focus on those without family history or other known risk factors.
During the investigation, researchers found that 15% of the participants had advanced adenomas, or pre-cancerous colon growths, compared to the typical 1-2% for their age group. Additionally, a staggering 41% had at least one adenoma, indicating a potential link between long distance running and an increased risk of colon cancer.
Experts theorize that intense endurance training can cause repeated “intestinal stress” during long runs, leading to damage and inflammation in the intestines. Over time, this could result in mutations and the development of polyps.
While the results of the study are not definitive and have not yet undergone peer review, they serve as a cautionary tale for extreme distance runners. Dr. Cannon emphasizes the importance of monitoring symptoms such as bleeding, persistent diarrhea, or abdominal pain, as these could be indicators of a more serious issue.
Despite the potential risks highlighted in the study, it’s important to note that exercise in moderation is still beneficial for overall health. Dr. Cannon stresses that the benefits of regular exercise outweigh the potential risks associated with extreme endurance training.
As with any health-related concern, it’s essential to consult with a healthcare professional if you experience any concerning symptoms. While long distance running may have its drawbacks, maintaining a balanced lifestyle that includes regular exercise and a healthy diet remains key to overall well-being.
This article was rewritten and adapted from an original piece on Fox News, preserving the key points and main findings of the study on long distance running and colon cancer risk.
