TUESDAY, Sept. 14, 2004 (HealthDayNews) -- A daily walk around the block, a few laps in the pool, a vigorous game of soccer: studies suggest exercise is extending the lives of women who've survived breast cancer, even as it lifts their spirits.
"Exercise empowers these women with a tool that's there at their disposal," said Dr. Cheryl Perkins, senior clinical advisor at the Susan B. Komen Breast Cancer Foundation, one of the nation's largest organizations dedicated to fighting the disease.
A groundbreaking study involving more than 2,100 women, released earlier this year, found that even moderate amounts of regular exercise -- like a half-hour walk every day -- could reduce a woman's risk for breast cancer recurrence by one-quarter to one-half.
"The benefit correlated with the amount of exercise. So, the more exercise, the better survival," Perkins said.
The reasons behind physical activity's positive effects on breast health remain unclear.
"One of the biological theories as to why exercise might be a good tool for reducing risk or in prevention is that it might reduce obesity, and obesity is known to increase circulating estrogen," Perkins said. High levels of circulating estrogen are thought to greatly increase a woman's risk for breast cancer and breast cancer recurrence.
But there could be other factors involved, since "we know that physical activity acts directly and indirectly" in reducing disease, said Debbie Saslow, director of breast and gynecologic cancer at the American Cancer Society. She pointed out that exercise has also been shown to lower risks for other cancers, including malignancies of the colon, endometrium, kidney and esophagus.
Women who are currently undergoing some form of chemotherapy should consult with their doctor before engaging in vigorous exercise regimens. "Some chemotherapy medications affect cardiac function," Perkins said. "And some affect bone density -- especially in older women, you might have bone density problems already."
There might also be some limits placed on excessive or strenuous arm movement among patients experiencing a treatment-related swelling of the underarm lymph nodes, a condition called lymphedema. "Because of the risk of lymphedema, we don't recommend that patients engage in really heavy weightlifting, for example," Saslow said.
Still, for most breast cancer survivors past the active-treatment stage of their care, "there's no limit as far as the capacity to do vigorous exercise," she said.
Of course, exercise can be a tonic for the mind as well as the body.
"It simply increases your sense of wellness," Perkins explained. "It helps increase your stamina in the long run. It's good on a lot of levels."
Perkins should know, since she's a long-term breast cancer survivor herself. She credits regular exercise with helping her stay fit in her fight against the disease.
"I've always been physically active, and get out every day. I have two wirehaired fox terriers and they move a lot. That's a reason, even when I don't want to, to get moving," she said. "And it makes you feel better."
It's fitting, then, that the Komen Foundation sponsors the annual "Race for the Cure" in cities across America, enlisting the hearts, minds and feet of breast cancer survivors and those who love them, in an effort to raise money for research.
"That's the visual symbol of all this," Perkins said.
"There's a lot we don't know about breast cancer -- what causes it, what increases your risk and what doesn't," she said. "But exercise is something a woman can do, and evidence is mounting that it's something that decreases risk and may make a real difference in survival."
For more on breast cancer, and efforts to find a cure, visit the Susan B. Komen Breast Cancer Foundation.