Moderate to vigorous exercise may be the easiest way to avoid colon cancer -- at least for men, according to a new study.

John Knudson got involved with this study for two reasons: he wasn't exercising and his colonoscopy had just come back abnormal.

“The doctor described me as a regular polyp farm so I figured there must be something going on,” he said.

So John began running six days a week.  

“We found that in men exercising regularly for an hour a day for a year significantly reduces the amount of proliferation in the men’s colon,” said Dr. Anne McTiernan of the Fred Hutchinson Cancer Research Center.

Proliferation refers to the cell growth that leads to the formation of polyps which, in turn, can become cancerous.

One interesting finding: all men in the exercise group benefited no matter what their body weight. But the same cannot be said for women, at least not in this study.

KING

John Knudson has become a dedicated runner.

“No unfortunately, but that doesn't mean there aren't other excellent reasons for women to exercises,” McTiernan said.

For John this study proved life-changing. Not only did his latest colonoscopy show improvement, he lost weight and gained a new passion.

“You start training and you think, I could try that 5k race and it goes okay, I could do that 8k, and it’s not that further to a half (marathon), but it's a big leap to the full,” he said.

But now he has the finisher's medal to prove it.

Although women did not show benefit in this study, previous studies have suggested otherwise, and it is thought that exercise can protect against breast cancer

That’s the subject of another study now under way at the Fred Hutchinson Cancer Research Center.

Volunteers are still needed. To qualify women need to be sedentary, overweight and postmenopausal. For more information, call (206) 667-6444.