Get fit now, and you might stave of lung or colorectal cancer when you’re older. According to a new study of 14,000 middle-aged men, those who could run an eight-minute mile had 55 percent lower risk of lung cancer and 44 percent less risk of colorectal cancer later in life than men who could muster only an 11.5-minute mile. And although being fit did not affect their odds of developing prostate cancer, the fit guys who did wind up with prostate, lung, or colon cancer were 32 percent less likely to die from their disease.
Previous research has suggested that cardiorespiratory fitness (CRF) can impact cancer risk. However, this is the first study to show that CRF is foretelling of site-specific cancer incidence and the resulting risk of death. "Individuals with higher CRF tend to have lower circulating concentrations of metabolic and sex steroid hormones, enhanced immunity, and less inflammation and oxidative injury," says lead researcher Dr. Susan Lakoski, an associate professor of medicine at the University of Vermont. "These effects act in concert to inhibit tumor development and decrease the risk of cancer-specific mortality."
As for why these factors don’t seem to offer the same level of protection to the prostate, "the relationship between fitness and prostate cancer risk is controversial," Lakoski says. "It’s possible that the men with higher CRF were more likely to undergo more frequent preventive screenings and thus had a greater opportunity to be diagnosed as having localized prostate cancer."
But the key takeaway regarding prostate cancer is that men who were physically fit before getting the disease were way less likely to succumb to it than their out-of-shape counterparts. "This speaks to the importance of being fit in midlife to improve survival," Lakoski says, "even if you do end up developing lung, prostate, or colorectal cancer later in life."