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This just in from Runner's World: "Exercise Fights Cancer Tumors Directly."
A heartening headline, no? A great many caveats are surely in order — the eternal "rats are not humans," in particular — but the piece describes interesting research suggesting that, to anthropomorphize a bit, tumors don't like it when we exercise. From Runner's World:
Kansas State University exercise physiologist Brad Behnke has been studying prostate-cancer tumor growth in rats that either exercise or are sedentary. As with humans, rats divert blood flow to the muscles when exercising. The result, in Behnke’s research to date, is a 200 percent increase in tumor blood flow during exercise.
That sounds like it could be a bad thing, at least if more blood flow “fed” tumor growth, and accelerated metastasis (spread of the disease to other organs). However, the opposite is what occurs, according to Behnke.
“When a tumor lacks oxygen, it releases just about every growth factor you can think of, which often results in metastasis,” he explained to Runner’s World Newswire by email. “Simply speaking, the tumor says, ‘I can’t breathe here, so let’s pick up and move somewhere else in the body.’”
When a tumor is bathed in oxygen, on the other hand, its activity tends to slow. In an earlier paper, Behnke demonstrated a 90 percent decrease in “tumor hypoxia” (low oxygen) among rats that engaged in long-term, moderate-intensity treadmill exercise. “As far as I know, this is the largest reduction in tumor hypoxia of any intervention, including drugs,” he said.
Another study by a different group of researchers has shown that aerobic exercise can lead to “normalization of the tissue microenvironment in human breast tumors.” In other words, exercise can help the tissue return to its pre-tumor state, or forestall development of a more aggressive and dangerous cancer.
Behnke is also exploring whether exercise could help make anti-cancer therapies like radiation more effective.
Hat-tip to Tom Anthony.