New Research: Getting Up From Your Desk Can Put the “Breaks” on Cancer
Experts Urge Americans to Rethink Outdated Notions of Physical Activity
WASHINGTON, DC — As many as 49,000 cases of breast cancer and 43,000 cases of colon cancer occurring in the U.S. every year are linked to a lack of physical activity, according to estimates presented today at the American Institute for Cancer Research annual conference. The estimate underscores the critical role that both activity and inactivity play in the development of specific cancers.
At the AICR Annual Research Conference on Food, Nutrition, and Physical Activity in Washington, experts presented data from a new paper on physical activity and breast cancer prevention and reviewed the mounting evidence that a brisk daily walk helps to reduce several key biological indicators of cancer risk, including sex hormone levels, insulin resistance, inflammation and body fatness.
The researchers also presented new findings from the emerging field of sedentary behavior research, which is finding that sitting for long periods of time can increase some of those same indicators of cancer risk, even among people who exercise daily.
“Taken together, this research suggests that every day, we’re each given numerous opportunities to be active and protect ourselves from cancer, not one,” said AICR spokesperson Alice Bender, MS RD. “We need to start thinking in terms of make time and break time.”
Based on these research findings, AICR is urging Americans to make time for physical activity and break every hour of sitting with 1 to 2 minutes of activity. These breaks can be as simple as walking to a colleague’s office instead of sending an email or going to the kitchen to get a glass of water.
“Making time to get at least half an hour of moderate to vigorous activity every day is great, and more Americans need to do it, but those 30 minutes represent only a sliver of our day,” Bender stated. “This new research on break time suggests there are small things we can do in the other 15 hours and 30 minutes we spend awake that also make a big difference.”
Make Time: Physical Activity Clearly Lowers Risk of Cancer
Providing the latest evidence of the protective link between physical activity and various cancers, Senior Research Epidemiologist Christine Friedenreich, PhD, of Alberta Health Services-Cancer Care in Canada, presented just-published findings from the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial. The latest results from this trial involve C-reactive protein, a marker of inflammation, which is linked to cancer risk. In a study appearing in the October issue of the journal Cancer Prevention Research, moderate to vigorous daily activity reduced C-reactive protein levels among post-menopausal women.
Although researchers have not yet identified how inflammation increases cancer risk, it is known that the inflammation process produces cytokines (immune-response chemicals that encourage cell proliferation and suppress cell death) that contribute to increased cancer risk. Previous studies have shown that the immune cells activated by the inflammatory response, such as macrophages and neutrophils, release reactive elements like oxygen and nitrogen, which can damage the DNA and produce mutations.
Dr. Friedenreich’s research demonstrates that even in previously sedentary postmenopausal women, a moderate- to vigorous-intensity exercise program results in changes in several biomarker levels that are consistent with a lower risk for postmenopausal breast cancer.
By extrapolating data from the ALPHA trial as well as previous epidemiological investigations involving adiposity, insulin resistance, mammographic density, sex hormone levels and other indicators of cancer risk, Dr. Friedenreich reported that engaging in moderate activity, like brisk walking, can significantly reduce the risk of certain cancers.
“In breast and colon cancers, for example, we’re seeing overall risk reductions of about 25 to 30 percent associated with higher levels of physical activity. With prostate cancer the evidence isn’t as strong but it’s still there – about 10 to 20 percent lower risk. For endometrial cancer, we are finding about 30 to 35 percent risk reduction with more physical activity.
“These numbers are powerful,” she said. “The bottom line: For many of the most common cancers, it seems like something as simple as a brisk walk for 30 minutes a day can help reduce cancer risk.”