In her most recent work, Friedenreich and her colleagues have found an association between exercise and the reduction of markers of inflammation, such as one called C-reactive protein, which might explain how exercise reduces the risk of breast cancer.
At the moment there is no conclusive evidence that increases in these markers of inflammation actually cause cancer or increase the risk of developing cancer, Friedenreich noted. It's probably a much more complicated process, she said.
"It's a bunch of different mechanisms that are going to have an impact," she said. "We think there are probably pathways through body fat, through hormones, through insulin resistance. Inflammation is one way cancer is affected; I wouldn't say it's the primary one, it's just one of the pathways.".
The study also appears in the October issue of the journal Cancer Prevention Research.
It's not just lack of exercise that increases these markers of inflammation -- just sitting around or leading a sedentary life style may have the same effect. Friedenreich's presentation also describes findings from a study first published in 2009 in the British Journal of Sports Medicine. It suggested that simply sitting around watching TV can cut years off yours life.
To counteract the risk of leading a sedentary life, Friedenreich suggests regular exercise. But she also suggests that taking breaks from sitting, especially at work, will help lower inflammation and also the risk of cancer.
"Too much sitting, sedentary behavior, actually increase the risk of cancer," she said. "Some of the mechanisms seem to be the same as for lack of physical activity. If you can break up your sitting time, even by little bits, that can help reduce your risk of cancer," Friedenreich said.
Experts estimate that people sit about 15.5 hours a day
All rights reserved