Can Exercise Help Prevent Cancer?
It's common knowledge that the best way to do what you can to prevent cancer is to live a healthy lifestyle. That means eating well, maintaining a healthy weight, getting screened for cancers according to a schedule your doctor recommends, applying sun block when your exposed to ultra-violet rays, reducing stress to build your immune system, etc. Does exercise play a role in cancer prevention as well?
Exercise helps prevent obesity
According to the National Cancer Institute, obesity and physical inactivity may account for 25 to 30 percent of several major cancers:
A report in the New England Journal of Medicine in 2003 estimated that 14 percent of cancer deaths in men and 20 percent of cancer deaths in women were caused by overweight and obesity.
Other research has shown:
—The Nurses Health Study (with more than 120,000 nurses participating) has shown that women who exercise vigorously for seven hours per week can reduce their risk of breast cancer by 20 percent. It also has shown that exercise may improve the life expectancy of women who develop cancer.
—Exercise speeds up the digestive process, and this seems to decrease the chance of developing colon cancer.
—Research in England showed that doing housework for four or more hours per day can reduce a woman's risk of endometrial cancer by 30 to 40 percent.
—A study in Canada showed that women who had high levels of exercise that was classified as moderate had a 33 percent reduction in ovarian cancer risk.
Exercise helps decrease stress
Getting regular exercise helps relieve stress, which in turn is good for the immune system. And a strong immune system is better able to fight cancer.
The American Cancer Society recommends that people get at least 30 minutes of moderate activity at least five days per week. At this stage of our knowledge of cancer, it's not possible to prescribe a specific amount and type and level of difficulty that will definitely prevent cancer. But signs point to the notion that getting exercise helps and certainly doesn't hurt.
It's always good to check with your doctor before you start any exercise program. But a good rule of thumb in terms of an exercise program for a reasonably healthy person is to try to get some activity nearly every day. Thirty minutes is a good goal, but getting a little more is even better. And mixing it up is beneficial. Try vigorous activity a couple of days a week, and then take it down to moderate for the other days.
American Cancer Society; National Cancer Institute; Cancer Epidemiology Biomarkers and Prevention; New England Journal of Medicine, 348(17):1625-1638