Brisk walking or other daily physical activity is one key step to lower the risk of breast cancer for women of all ages, yet far too few Americans recognize this link, according to experts at the American Institute for Cancer Research (AICR). To mark National Breast Cancer Awareness Month, AICR is highlighting this finding from its recent report, an analysis of the global research on lifestyle and breast cancer risk.

AICR's latest awareness survey conducted earlier this year found that only four of ten Americans (39 percent) know that physical activity plays a role in cancer risk. Along with breast cancer, physical activity protects against colon and endometrial cancers.

“Our recent report, summarizing the research from around the world, showed that there is strong evidence that regular vigorous physical activity reduces the risk of breast cancer in both pre- and post-menopausal women,” said Nigel Brockton, PhD, AICR's Director of Research  “Women of all ages can lower their risk of breast cancer by adding vigorous physical activity to their daily lives. That’s a simple message that can have a powerful impact.”

AICR research estimates that one of every three US breast cancer cases annually could be prevented by limiting alcohol intake, increasing activity and being a healthy weight.

Vigorous Activity Now Lowers Risk for Younger Women 

Diet, Nutrition, Physical Activity and Breast Cancer showed, for the first time, that vigorous exercise such as cycling or running helps prevent pre-menopausal breast cancer. Evidence also confirmed vigorous activity lowers risk for post-menopausal breast cancers, the most common form of this cancer. 

For vigorous exercise, pre-menopausal women who were the most active had a 17 percent lower risk and post-menopausal women had a 10 percent lower risk of developing breast cancer compared to those who were the least active. 

Both vigorous and moderate activities linked to lower risk of post-menopausal breast cancer. Total moderate activity, such as walking and gardening, linked to a 13 percent lower risk when comparing the most versus least active women.

Weight and Limiting Alcohol

The report showed other key steps that women can take to lower their risk, including:

Get to – and stay - a healthy weight: Being overweight or obese is one of the strongest factors to increase risk of post-menopausal breast cancer. Excess fat can promote chronic inflammation, and increase blood levels of insulin and related hormones that can spur the growth of cancer cells. Along with breast cancer, overweight and obesity increases risk of ten other cancers, including ovarian, endometrial and colorectal. 

Work to maintain a healthy weight or not gain any more: Greater adult weight gain also linked to increased risk of this type of breast cancer. 

Limit alcohol: Drinking even one glass of wine or other alcoholic drink a day on a regular basis linked to higher risk of breast cancers. Risk continues to rise with higher amounts. Alcohol or ethanol is a carcinogen, which could damage DNA and increase levels of hormones that fuel cancer. AICR recommends that for women who do drink, limit the amount to one glass or less a day.

Notes Alice Bender, MS, RDN, AICR’s Director of Nutrition Programs: “Our report focused on lowering risk for breast cancer, but research also shows that for everyone, including cancer survivors, taking these same lifestyle steps can help lower risk for chronic diseases like heart disease and type 2 diabetes.”

For new moms, the report found that breastfeeding reduces the risk of both post- and premenopausal breast cancers.

Breast cancer is the most common cancer among women worldwide and in the United States (except for non-melanoma skin cancer).

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