Physical activity is key
By Nicole Rogers, MPH, CHES for The Health Collaborative
Cancer remains one of the top two causes of death in Bexar County, according to information released recently by The Health Collaborative in its 2006 Bexar County Community Health Assessment.
Together, cancer and heart disease claim the lives of 48 percent of all Bexar County residents. By the time people have developed cancer or heart disease, the community can do little for them other than help ensure access to the health care system. Clearly, a greater emphasis on prevention is needed.
American Cancer Society research suggests that one-third of the 550,000 cancer deaths which occur in the United States each year are due to insufficient physical activity and unhealthy diet. Research also continues to show that, for the majority of Americans who do not smoke, being physically active and eating a healthful diet are the most important ways to reduce the risk of cancer.
While it has long been an accepted fact that physical activity reduces one’s risk of heart disease, it is still news that physical activity also can reduce the risk of cancer. Physical activity works in a variety of ways to reduce risks, including controlling weight and influencing hormones. Recent studies documenting the importance of physical activity in reducing the risk of cancer include the following:
• A study led by a professor at the Harvard School of Public Health and Harvard Medical School found that being an athlete in college can win women a competitive edge against breast cancer. A 15-year follow-up of almost 4,000 female athletes and nonathletes revealed that women who were less active had significantly more cases of breast cancer than those women who were more active. According to the study, exposing women to physical activity during their college years or earlier may decrease the risk of breast cancer in women of all ages by 17 percent. This strongly confirms the lifetime advantage of participating in organized athletics before and during college, and it is an important finding at a time when more and more women participate in organized collegiate sports.
• A study conducted by the American Cancer Society in 2003 found that postmenopausal women who were very active lowered their risk of breast cancer by nearly 30 percent. The report, published in the Journal of Cancer Causes and Control, indicated that, although any physical activity appeared to have some benefit, the 30-percent reduction in breast cancer rate occurred in women whose exercise was the equivalent of swimming, running or jogging at least six hours a week. The report said that women would achieve the same effect by walking or dancing, but they would just need to do it for twice as long.
• Researchers from the University of Utah found that both men and women lowered their risk of cancer with physical activity. Published in the American Journal of Epidemiology, the study showed that men and women who exercised the equivalent of jogging five or more hours a week lowered their risk of colorectal cancer by 40 to 50 percent.
The American Cancer Institute says that there is convincing evidence that physical activity can lower the risk of certain kinds of cancer:
Colon Cancer Risk
Individuals who are physically active can reduce their risk of developing colon cancer by 40 to 50 percent, with the greatest reduction in risk among those who exercise the most. A decrease in the risk of colon cancer has been consistently reported for physically active men. Many studies have reported a reduction in colon cancer risk for physically active women, though this link has been less consistent than the link for men. Many researchers believe that physical activity accelerates the movement of food through the intestine, thereby reducing the length of time that the bowel lining is exposed to potential carcinogens. Increased physical activity also causes changes in insulin resistance, metabolism and hormone levels, which may help prevent tumor development. Physical activity may also alter a number of inflammatory and immune factors, some of which may influence colon cancer risk.
Breast Cancer Risk
Physically active women have up to a 40-percent reduced risk of developing breast cancer. Most evidence suggests that physical activity reduces breast cancer risk in both pre- and post-menopausal women. Although a lifetime of regular, vigorous activity may be of greatest benefit, women who occasionally engage in physical activity also experience reduced risk compared to inactive women.
Prostate Cancer Risk
Physical activity reduces men’s risk for prostate cancer by 10 to 30 percent. The potential biological mechanisms that explain this association are as yet unknown.
Endometrial Cancer Risk
Research also suggests that women who are physically active have a 30- to 40- percent reduced risk of endometrial cancer, with the greatest reduction in the risk among those who exercise the most. Changes in body mass and alterations in levels and metabolism of sex hormones, such as estrogen, are the major mechanisms thought to explain the association between physical activity and endometrial cancer risk.
Are you recovering from cancer?
Research also has indicated that physical activity is helpful for individuals recovering from cancer. A study published by the American Cancer Society (ACS) said that patients who participated in an aerobic exercise program after undergoing chemotherapy experienced better physical performance, increased hemoglobin levels and less fatigue than patients who did not exercise. Fatigue experienced during chemotherapy and radiation therapy is a significant contributor to a decreased quality of life for most cancer patients. The program consisted of treadmill walking five days a week for six weeks, gradually increasing in duration from three minutes per day to 30 minutes per day. By exercising, patients were able to keep their muscles in shape, which made daily tasks easier.
Nicole Rogers, MPH, CHES, is the executive director of The Health Collaborative, a cutting-edge, public-private model for solving community health issues. The mission of the organization is to improve the health status of the community through collaborative means. Representatives of this group are dedicated to the health and well-being of our community in the spirit of collaboration. Partners include the major health systems in San Antonio, Metro Health, the YMCA of Greater San Antonio, Community First Health Plans, Methodist Healthcare Ministries and a community representative. For more information, visit www.healthcollaborative.net.
