How exercise affects cancer

Philip J. Goscienski, M.D.

May 2011

About half of our population will develop cancer and nearly a third will die from it. More than half of cancers are caused by lifestyle factors and smoking is the most important of these. However, we can take some other steps to prevent or postpone this second leading cause of death.

Exercise helps us to live longer and it's not just because those who are well are able to exercise while those who are ill cannot. Although the heart and lungs are the main beneficiaries of regular, moderately intense physical activity, every organ in the body has something to gain and that includes resistance to cancer.

As body fat increases, so does the likelihood of cancer, especially cancer of the breast, uterus, colon, liver, gallbladder, esophagus, pancreas and kidney. Obese women have higher levels of estrogen, which plays a role in the conversion of normal cells into malignant ones. Although the precise mechanism by which estrogen causes cancer is not well defined it's possible that inflammatory cells that are manufactured in fat cells work together with estrogen to produce cancer. Exercising regularly, that is, almost every day, helps to prevent fat accumulation and it accelerates fat loss in persons who reduce their calorie intake sufficiently.

Women who exercise at least three days per week beginning in early adulthood have about one-third the risk of breast cancer as non-exercisers. Unfortunately, those who have a mother or sister with breast cancer are less likely to lower their risk, although the other benefits of exercise still apply.

Regular physical activity not only lowers the risk of colon cancer, it increases survival in those who have had the disease. Men who receive hormone therapy following surgery for prostate cancer experience less fatigue and enjoy a better quality of life if they exercise with weights three times a week.

Cancer specialists note an improvement in the coping effect among persons who have been exercising before and after their surgery. Survivors of breast cancer have better heart and lung function in addition to a better quality of life. Some of the benefit may be due to having more muscle mass that can serve as a storehouse of protein immediately following surgery, when the appetite is poor and food intake is less than normal.

The bottom line: long before you need it, build muscle and stamina with exercise. You can't do it after the fact.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at