Can long-distance running increase your risk of colon cancer? Maryland doctor explains what runners should know

Endurance training is known to improve overall health and a recent study linking it to colon cancer should not deter one from the exercise, shares Dr Sood.

Physical exercise has long been known as absolutely essential for maintaining good health. However, when a 2025 study revealed a possible link between extreme endurance running and colon cancer, it left many stunned.

While the claim does appear concerning, it should not immediately scare one away from long-distance running, according to Dr Kunal Sood, a Maryland-based physician in Anesthesiology and Interventional Pain Medicine.

Taking to Instagram on February 23, Dr Sood explained what the study actually found, and why details matter while interpreting such findings.

How is endurance training linked to colon cancer?

Dr Sood highlighted that the study has found only an association between long-distance running and colon cancer, and not any proof that one causes the other.

However, there has been a theory that prolonged and intense endurance training exercises can temporarily reduce blood flow to the intestines, he noted. As a result, during long runs, some people may experience short-term gut stress.

“Whether repeated episodes of that stress could contribute to long-term cellular changes is still theoretical and not proven,” stated Dr Sood.

The gut stress experienced is also dependent on other factors, he added, such as the diet followed, hydration level, use of supplements, training load, and genetics. All of these can differ in different high-mileage runners and can influence risk.

Why one should not stop endurance training

While any causal link between endurance training and colon cancer is yet to be established, there are multiple benefits of regular physical activity that have long been proven, stated Dr Sood.

This includes lowering the risk of many forms of cancer, including colon cancer, and improving overall long-term health. As per the Mayo Clinic website, these include:

• Controlling body weight
• Preventing and battling health conditions and diseases
• Improving mood
• Boosting energy levels
• Improving sleep quality
• Improving the experience of physical intimacy

“If there's any concern (about endurance training and colon cancer), it would likely apply to extreme endurance volumes, not typical running or exercise routines,” noted Dr Sood.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.

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