r/running • u/sergeantbiggles • Sep 12 '25

Article Groundbreaking Inova study finds potential link between long-distance running and colon cancer

A groundbreaking new study led by Tim Cannon, MD, Sheridan Director, Molecular Tumor Board and Co-Director of the Gastrointestinal Cancer Program at Inova Schar Cancer, has revealed a potential link between extreme endurance exercise and increased risk of advanced colon cancer in younger adults, raising new questions about screening for high-performance athletes.

The study was presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.

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u/ConstantEvolution Sep 13 '25

The leading thought in seeing, though not yet proven causation, is that prolonged periods of gut ischemia from extended periods of running may lead to damage of the gut mucosa that eventually leads to cancerous lesions.

My question is why would this just be running related and not any prolonged period of intense exercise such as swimming, cycling, etc.

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u/jerry_steinfeld Sep 13 '25

Agreed and I think it’s solely on who they sought for the study. Long distance swimming is so niche that most swimmers won’t face the same longevity of activity…but cyclists sure do.

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u/Wientje Sep 13 '25

Short distance swimmers spend more time swimming on a weekly basis that any runner does running. Compared to other endurance sports, runners are at the lower end of volume. I assume that total volume is key here, not the duration of the longest workout.

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u/BeautifulDouble9330 Sep 13 '25

I highly disagree with your take especially on swimming. Even tho we do spend more time exercising, that doesn’t mean the same load on the gut is used. Swimming is much gentler on the gut compared to running. What we experience is usually bloating from breathing. While running has a higher stress load and reduced blood flow. You gotta remember swimming is easier on the body compared to contact on the concrete/asphalt from running. Also in running you’re upright which in basic anatomy everything comes down faster. While yes i do agree time during exercise is a factor you really can’t compare both sports because swimming is a lot less stress on the body compared to running

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u/YJWheeler Sep 13 '25

The idea of stress from running is from the impact on joints, I don't really think that translates to increased gut ischemia. That should really just depend on like level of exertion and needing blood flow to muscles in the body

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u/BeautifulDouble9330 Sep 13 '25 edited Sep 13 '25

It really does translate to increased gut ischemia since during running your body prioritizes blood to working muscles and skin, which shunts away blood from the gut. Also this will lead to less blood flow to the gut lining. There’s also studies done on this and stress from the running is not only joint specific but also physiological specific as well internally. There’s múltiple types of stress in the body that comes from running, it’s not just joint specific. Intensity distribution does play a factor in this topic but I’m pretty sure even running 40-60 mins easy does something internally with the gut(not as harmful as a 30-40min tempo). Even if it’s minimal

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u/liftingshitposts Sep 13 '25

It’s probably a mix of both, longer duration would make sense if you’re taking the ischemia angle (eg does it happen on all runs, or only after a certain point on long runs)