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Who knew kicking a soccer ball could decrease her risk of developing breast cancer?
We all know that physical activity is important and has many health benefits. It can improve endurance and muscular fitness, affect body composition, improve bone health, and improve the cardiovascular system. However, what many of us don't know is that physical activity also reduces girls' future risk of developing breast cancer later in life. Read more to learn about how physical activity lowers girls' future risk of developing breast cancer later in life.
How does exercise affect breast cancer risk?
Researchers believe that breast cancer risk is directly related to the total number of ovulatory cycles a woman experiences during her lifetime and anything that can reduce the number of ovulatory cycles may decrease a woman's risk for breast cancer. During adolescence, moderate physical activity may be one way to decrease breast cancer risk because it can reduce the frequency of ovulatory cycles in girls1. Strenuous physical activity, however, can delay the onset of menstruation2.
What evidence is there for this theory?
In one study researchers monitored 168 high school girls for 6 months and found that as girls exercised more, they experienced more menstrual cycles without ovulation3.
In another study, researchers compared women with breast cancer and those without it. The researchers found that the number of hours a woman was physically active per week from when she started menstruation until one year before a breast cancer diagnosis was strongly linked to reduced breast cancer risk even when controlling for other factors4.
Other researchers interviewed women with breast cancer and those without breast cancer in a study published in 1995. These researchers found that women who reported any strenuous physical activity during ages 14 to 22 years old had a modest reduction in the risk of breast cancer but those who were vigorously active at least once a day had a 50% reduction in breast cancer risk5.
More recently, a review of 19 research studies focused on physical activity and breast cancer risk in adolescence and young adulthood found a nearly 20% reduction in breast cancer risk between those who were the most physically active and those who were the least physically active. In addition, each one-hour increase of recreational physical activity per week during adolescence was associated with a 3% reduction in risk6.
How active should my daughter be?
According to the guidelines set by the U.S. Department of Health and Human Services, children and adolescents (age 6 to 17) should get 1 hour or more of physical activity every day. Most of the 1 hour or more a day should be either moderate- or vigorous-intensity aerobic physical activity. As part of their daily physical activity, children and adolescents should do vigorous-intensity activity at least 3 days per week. They also should do muscle-strengthening and bone-strengthening activity at least 3 days per week.
What can I do to help my daughter become more active?
- Sign her up for a sport or activity she enjoys. Soccer is just one example of a sport or activity in which your daughter can participate.
- Walking, dancing, leisurely bicycling, ice and roller skating, horseback riding, canoeing, yoga, volleyball, golf, softball, badminton, doubles tennis and downhill skiing are considered moderate intensity physical activities.
- Jogging or running, fast bicycling, circuit weight training, aerobic dance, martial arts, jumping rope, swimming, soccer, field or ice hockey, lacrosse, singles tennis, racquetball, basketball, and cross-country skiing are considered vigorous intensity physical activities.
- Incorporate physical fitness into family and everyday activities. For example, try hiking with your family or next time you head to the library, walk there together.
- Limit her screen time to two hours or less per day. Screen time includes time spent watching TV, being on computer and playing video games.
- Be a role model for your daughter by being physically active yourself.
For more information about local physical fitness resources for children and adolescents in Marin please visit the following websites:
Hang outs and Recreation centers in Marin County:
http://healthyteensmarin.org/resources/teen_resource_hang_outs.htm
List of Physical Activities:
http://marinonthemove.org/activities.cfm
Marin Health and Human Services Nutrition and Wellness Program:
http://www.co.marin.ca.us/depts/HH/Main/nwp/nutritionwellness/index.cfm
For more information about how to exercise may reduce your daughter's future risk for breast cancer, please visit the following resources:
Tips to Reduce Your Risk for Breast Cancer:
http://www.zerobreastcancer.org/research/7ways_riskreduction.pdf
Breast Cancer Questions and Factors, Environmental Risk Issues, and Health Tips:
http://zerobreastcancer.org/education/faq.pdf
What Should I Know About Breast Cancer?
http://zerobreastcancer.org/education/zbc_adolesproj_broch_sm.pdf
Breast Cancer Tips for Latina Teens, Young Women and Families:
http://zerobreastcancer.org/education/zbc_latinabrochespnl.pdf
Top Twelve Breast Cancer and Environment Messages for Teens:
http://zerobreastcancer.org/education/top12bcmsgs.pdf
American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention, written by Bay Area Breast Cancer and the Environment Research Program investigator Dr. Lawrence Kushi.
http://caonline.amcancersoc.org/cgi/reprint/56/5/254
Contact:
Casandra Aldsworth, MPH
Updated October 2010
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