Effect of Amount and Type of Exercise on Experimentally Induced Breast Cancer
Epidemiologic and laboratory data indicate that certain patterns of physical activity may alter the risk for cancer. Exercise is a type of physical activity being promoted for its health benefits. The influence of exercise on the induction of breast cancer in an animal model for the disease was investigated. The data presented indicate that both the intensity and duration of exercise affect the promotion stage of chemically induced mammary carcinogenesis. Whereas certain patterns of exercise inhibited the tumorigenic response and yielded a protective effect that was sustained even after exercise was discontinued, others had either no effect or accelerated the rate of mammary tumor appearance. It is concluded that further characterization of patterns of physical activity that alter the tumorigenic process in the breast and at other cancer sites is warranted. Experiments are also needed to identify the mechanisms that underlie cancer-preventive as well as cancer-enhancing effects of exercise. A goal of research in this area should be to determine if the quantity and quality of exercise needed to attain cancer preventive effects differs from that which is recommended for health-fitness benefits.
KeywordsPhysical Activity Mammary Tumor Caloric Restriction Mammary Carcinogenesis Mammary Tumorigenesis
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