Running and Breast Cancer

Exercise doesn’t just lower the number on the scale, studies now show that it can also reduce breast cancer risk.

The American Cancer Society predicts that in 2011, some 288,000 American women will be diagnosed with breast cancer and that the disease will take the lives of 39,520 American women. These numbers could decrease significantly if more women were active, says Dr. Alvaro Carrascal, the American Cancer Society Senior Vice President of Cancer Control for New York and New Jersey.

“The relationship between physical activity and breast cancer has been studied widely and several studies have shown that active women have a lower risk of getting breast cancer than sedentary women,” Alvaro says.

The National Cancer Institute has also funded studies exploring the role of physical activity and cancer risk and they have found that across around 50 studies, the risk of developing breast cancer was 20 percent lower among the most active women than amongst the least active.

These studies found that exercise lowered breast cancer risk for both pre- and post-menopausal women, but risk reduction was slightly greater for women who already had gone through menopause.

Yes, gardening andhousework count

Very young women also benefit greatly from exercise, Carrascal says. According to Carrascal, high levels of vigorous to moderate activity during adolescence have been shown to cut down breast cancer risk significantly later in life. Moderate exercise includes activities like walking, housework, gardening and biking, while vigorous exercise is defined as activities that increase heart rate, sweat and rate of breathing. All women should do a mixture of both to reduce breast cancer risk and the American Cancer Society suggests that everyone should exercise for at least 45 to 60 minutes, five times a week.

Researchers haven’t yet concluded exactly why exercise reduces breast cancer risk, but Carrascal says it may be because physical activity prevents tumor development by reducing insulin levels, hormone levels and improving the immune system response. Exercise also can reduce weight gain and obesity, both of which increase the risk of getting most types of cancer, says Carrascal.

Obesity is estimated to cause 14 percent of cancer deaths in men and 20 percent of cancer deaths in women, according to the National Cancer Institute. Breast cancer risk in particular increases for those who have gained weight after reaching adulthood, says Carrascal. Those who have gained 20 or more pounds after age 18 are 40 percent more likely to develop breast cancer than they otherwise would have been had they not gained the weight, says Carrascal. Those who have gained 70 or more pounds since age 18 have doubled their risk of getting breast cancer. This is especially dangerous for postmenopausal women, who already are at a higher risk of breast cancer.

Obesity also can be detrimental to women who already have been diagnosed with breast cancer. According to the National Cancer Institute some studies have shown that obesity may double the risk of recurrence and death amongst breast cancer survivors.

But it is never too late to reduce your risk, regardless of age or cancer status, according to Carrascal.

“The risk of getting breast cancer goes down when you lose the weight,” he says. “Anytime you lose weight and maintain it you gain across the board.”

Women who are a healthy weight and have had breast cancer can still benefit from regular exercise.

Improved survival rates

Although it is too early to draw any strong conclusions regarding physical activity and breast cancer survival, some studies have shown that women who exercise three to five hours a week after a diagnosis of breast cancer — especially those with hormone responsive tumors — have improved survival rates compared with less active women, according to the National Cancer Institute.

Carrascal also recommends exercise for women who recently have had surgery to remove breast cancer.

“It can lower anxiety, reduce fatigue and in general it just helps you feel better about yourself,” he says. “But women should talk to their physicians first about when it is the right time to start an exercise regiment after recovering from breast cancer.”

Exercising regularly, not smoking or drinking excessively and maintaining a healthy diet is the best way to reduce breast cancer risk for everyone, says Carrascal.

Roughly one-third of all cancer incidences could be prevented by lifestyle changes, he says. However, breast cancer also can be caused by genetic mutations, family history and other non-lifestyle related factors.