Along with surgery, treatments such as radiation, chemotherapy, targeted therapies, and hormonal therapy medicines make breast cancer treatable. Still, because the treatments have unavoidable effects on healthy cells as well as cancer cells, there are pros and cons associated with each. Some possible unintended effects are heart damage.
Research shows that heart disease is the leading cause of death among women who have been diagnosed with early-stage breast cancer. Heart disease is especially lethal among women who are older than 65 and have other heart disease risk factors, such as high blood pressure or are obese, when they are diagnosed with early-stage disease.
Doctors wondered if exercise could reduce heart disease risk in women who were at higher risk for heart disease when they were diagnosed with breast cancer. A study suggests that exercise does help: The more the diagnosed women exercised, the more they lowered their risk of heart disease.
The study was published online on May 23, 2016 by the Journal of Clinical Oncology. Read the abstract of “Exercise and Risk of Cardiovascular Events in Women With Nonmetastatic Breast Cancer.”
To do the study, the researchers sent 2,973 women diagnosed with early-stage breast cancer (stage I, stage II, or stage IIIA) a questionnaire about how much physical activity and exercise they did per week. The women were all part of two other studies: the Life After Cancer Epidemiology (LACE) study and the Pathways study. The characteristics of the women in the study were:
- half were older than 58 and half were younger than 58
- about 72% were white
- half the women had a body mass index (BMI) that was higher than 27.5 and half had a BMI that was lower; BMI between 25 and 29.9 is considered overweight and BMI of 30 or higher is considered obese
- 6.5% currently smoked, 40.8% were former smokers, and 52.7% never smoked
- 63.5% were postmenopausal
- 82.2% were diagnosed with estrogen-receptor-positive disease
- 15.5% were diagnosed with HER2-positive disease
- 57.5% had lumpectomy and 42.3% had mastectomy
- 55.9% had chemotherapy
- 52.3% had radiation therapy
- 75.3% had hormonal therapy
- 8.6% had Type 2 diabetes
- 39.1% had high blood pressure
- 25.7% had high cholesterol
The women were followed for about 8.5 years. During the follow-up period, the researchers looked to see if any women had heart problems such as coronary artery disease, heart attack, stroke, or abnormal heart rhythm.
The exercise survey results found that:
- 24.9% (741 women) of the women exercised for 2 or fewer hours per week
- 25.1% (747 women) of the women exercised for 2.1 to 10.3 hours per week
- 24.9% (741 women) of the women exercised for 10.4 to 24.5 hours per week
- 25% (744 women) of the women exercised for 24.6 or more hours per week
National guidelines recommend that adults who have been diagnosed with cancer get 9 or more hours per week of moderate exercise, including walking, swimming, or mowing the lawn.
The exercises the women did included walking, jogging, running, bicycling, swimming laps, and playing racquet sports.
Women who exercised the most were:
- at a healthy weight
- didn’t smoke
- had fewer heart disease risk factors
During the follow-up period, 862 cases of heart disease were diagnosed in the women, including:
- 203 women with coronary artery disease
- 307 women having a heart attack
Overall, the more the women exercised, the less likely they were to have heart problems:
- there were 262 heart disease cases in women who exercised 2 or fewer hours per week
- there were 243 heart disease cases in women who exercised for 2.1 to 10.3 hours per week
- there were 198 heart disease cases in women who exercised for 10.4 to 24.5 hours per week
- there were 159 heart disease cases in women who exercised for 24.6 or more hours per week
This difference in the number of heart problems was statistically significant, which means that it was likely because of the difference in the amount of exercise, rather than just due to chance.
Women who met national guidelines of 9 or more hours of exercise per week were 23% less likely to have heart problems compared to women who exercised for less than 9 hours per week. This link between 9 or more hours of exercise and a lower risk of heart problems wasn’t affected by the women’s age, menopausal status, breast cancer treatment type, or how many heart disease risk factors they had.
While this study only looked for an association between exercise and a lower risk of heart problems in women who were diagnosed with early-stage disease, there are many other benefits to regular exercise if you’ve been diagnosed with breast cancer:
- a lower risk of breast cancer coming back (recurrence)
- easier to maintain a healthy weight
- fewer and less severe side effects from treatment
- more energy
- better mobility
- more muscle mass and strength
- healthy bones
- better self-esteem and less stress
- better sleep
If you’re busy with work, household chores, and family matters, finding time to exercise almost every day can be hard. Exercising also can be extremely difficult if you’re recovering from breast cancer treatment. Still, it’s worth your while to make time to move.
It can help to break up your exercise into 20- or 30-minute sessions that add up to about 9 hours per week. Walking is a great way to start. Maybe you walk 30 minutes before going to work and 30 minutes on your lunch break. You can add a few more minutes by parking farther away from your building or taking mass transit. Or you can make plans to walk with a friend after work -- you’re more likely to stick with exercise if someone else is counting on you. Plus, you can socialize at the same time.
Visit the Breastcancer.org Exercise section for tips on exercising safely and how to stick to an exercise routine.