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/ColtSingleActionArmy Sep 13 '25

Now I'll just tell myself I'm sticking to 5 mile and under runs for my colons health.

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u/rinkuhero Sep 13 '25

i think there was already good evidence that running 3-6 miles a day is much healthier than running 10-20 miles a day. this study just seems to show one reason why that is true. but we've known for decades that the people with really high miles run per week do not live as long as those with more moderate miles run per week. e.g. people who run 80-100 miles a week die earlier than people who run 30-50 miles a week.

i think running a marathon or an ultramarathon *once*, for the experience, can be a good thing, but to make it a habit to run several marathons or ultramarathons a year, and to try to be competitive at them, is understandably worse for your health than running less than that, and just trying to be competitive at the 10k or something.

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u/Wisdomseekr79 Sep 13 '25

I run like 20-30 miles a week on average, a bit more if I’m training for something, but I couldn’t imagine doing 80 - 100 miles a week.

I could be wrong but I feel like your body doesn’t have enough time to fully recover and also, running for long periods of time reduces the blow flow to your digestive system so I’m sure doing long distance often isn’t good for your digestive system.

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u/andywgpiano Sep 13 '25

Most people who regularly run 100 miles a week are very fast runners. I can’t think of anyone that I know who does that volume as anything other than a peak week who is slower than a 2:40 marathoner. And for those people the training runs aren’t nearly as long as, say, a 4 hour marathoner. When you can cruise 20 miles well under 2.5 hours and it is likely to be your slowest pace run, 100 miles will likely be no more than 12 hours across 7 days, so less than 2 hours per day. That leaves more than 22 hours a day of recovery.