The Washington Post notes that past research “indicates that exercise helps some cancer survivors avoid recurrence of their disease.”
But a new study “offers an explanation of how, showing that exercise changes the inner workings of our muscles and cells, although more study is still needed…”
The study, published last month, involved 32 women who’d survived breast cancer. After a single session of interval training or weightlifting, their blood contained higher levels of certain molecules, and those factors helped put the brakes on laboratory-grown breast cancer cells. “Our work shows that exercise can directly influence cancer biology, suppressing tumor growth through powerful molecular signals,” said Robert Newton, the deputy director of the Exercise Medicine Research Institute at Edith Cowan University in Perth, Australia, and senior author of the new study. His group’s experiment adds to mounting evidence that exercise upends the risks of not only developing but also surviving cancer…
Scientists know contracting muscles release a slew of hormones and biochemicals, known as myokines, into our bloodstreams and have long suspected these myokines fight cancer. In some past studies with mice and healthy people, blood drawn after exercise and added to live cancer cells killed or suppressed the cancer’s growth… [The new study tested cancer cells in high-tech petri dishes with blood drawn from cancer survivors.] Drenched in plasma from either the interval trainers or the lifters, many cancer cells quit growing. Quite a few died. (The blood drawn before exercise had no effects.) The cancer-fighting impacts were greatest with the blood drawn after interval training. Why? Additional testing showed this blood contained the highest concentrations of certain, beneficial myokines, especially IL-6, a protein that affects immune responses and inflammation…
What these results mean, Newton said, is that “exercise doesn’t just improve fitness and well-being” in people who’ve had cancer. “It also orchestrates a complex biological response that includes direct anticancer signals from muscles…” Questions remain, of course. Can any type of exercise fight cancer? Newton and other researchers have doubts. The exercise in this study was strenuous, by design. “Earlier studies suggested that the stronger the exercise stimulus, the greater the release of anticancer myokines,” Newton said… Even the weight training in this study was less potent than the intense intervals. But Newton believes weight training remains key to cancer fighting. “People with cancer who increase their muscle mass through resistance training also experience greater rises in circulating myokines,” he said. More muscle means more myokines.