Breast cancer: can physical activity provide some protection?

Mary Calvagna, MS

Breast cancer is the second most common type of cancer among women in the United States (skin cancer is the first). Each year, more than 180,000 women are diagnosed with breast cancer.

According to the National Cancer Institute, a woman's chance of being diagnosed with breast cancer is:

From age 30 to 40	1 out of 257
From age 40 to 50	1 out of 67
From age 50 to 60	1 out of 36
From age 60 to 70	1 out of 28
From age 70 to 80	1 out of 24
Ever	1 out of 8

Although some risk factors have been identified, most women who develop breast cancer have none of the known risk factors. Current research, however, is searching for ways that women can better protect themselves from breast cancer.

An abundance of studies have shown that regular physical activity can help protect you from certain health problems, including:

• Heart disease and stroke
• High blood pressure
• Type 2 diabetes
• Obesity
• Back pain
• Osteoporosis

But can regular physical activity help protect you from breast cancer? A recent study published in Medicine and Science in Sports and Exercise* looked at almost 2,500 women in the hopes of answering this question.

The study compared 1,233 women who had been diagnosed with breast cancer to 1,241 women who did not have breast cancer. Using the Lifetime Total Physical Activity Questionnaire and trained interviewers, the researchers measured the women's activity levels throughout their lives. The frequency, duration, and intensity of occupational, household, and recreational activities were measured. The activities were categorized by intensity level: light activity, moderate activity, and heavy activity. The women were divided into four groups depending on the average number of hours they exercised per week.

The women with the highest level of weekly activity had a 31% lower risk of breast cancer when compared with the women with the lowest level of weekly activity. In addition, moderate activity was associated with a greater risk reduction than light or heavy activity. When the different types of activities were considered, occupational and household activities provided the greatest risk reduction. But, the study's authors attribute this finding to a low level of recreational exercisers in the study. The researchers concluded that women who do not get a lot of activity on the job or from household tasks, could benefit from recreational exercise.

In light of these research findings and the findings of previous studies that have highlighted the benefits of exercise, it seems like a good idea to get moving. Here are some tips to help you incorporate more movement into your busy day.

• Walk up stairs instead of taking an elevator or escalator.
• Get off the bus before your stop and walk the remaining distance.
• When parking your car, pick a spot farther from the entrance of where you are going.
• Work in the garden. Mow the lawn with a push mower. Rake leaves.
• Instead of driving, walk or bike ride to the corner store.
• Stretch, lift weights, or pedal a stationary bike while watching television.
• Play actively with children.
• Take a brisk 10-minute walk in the morning, at lunch, and after dinner.
• Turn on your favorite music and dance—either with someone or by yourself.

* "Relation between intensity of physical activity and breast cancer risk reduction," by CM Friedenreich, et al. Medicine and Science in Sports and Exercise, September 2001, pp. 1538 -1545.