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. One possible unintended effect is 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 women who regularly exercised before they were diagnosed with breast cancer had a lower risk of heart problems related to treatment.
A study suggests that regular exercise does help: Women who did 5 hours of moderate exercise per week before being diagnosed with breast cancer were much less likely to have heart problems or die from heart disease after treatment compared to women who exercised for less time before being diagnosed.
The research was presented at the American College of Cardiology’s 66th Annual Scientific Session on March 18, 2017. Read the abstract of “Associations Between Exercise Prior to and Around the Time of Cancer Diagnosis and Subsequent Cardiovascular Events in Women With Breast Cancer: A Women’s Health Initiative (WHI) Analysis.”
The research is part of the very large Women’s Health Initiative Clinical Trial and the Women’s Health Initiative Observational Study. Both studies are commonly called the WHI. Together, the two studies include information from more than 161,608 postmenopausal women who were ages 50 to 79 when they joined from 1993 to 1998. The WHI wants to find any links between health, diet, and lifestyle factors and health problems such as cancer.
In this analysis, the researchers looked at information on 4,015 women in the WHI who were diagnosed with non-metastatic breast cancer. The women filled out exercise surveys throughout the study. Based on the amount of exercise the women did, the researchers put them into one of four groups:
- low: fewer than 2.5 MET hours per week; about an hour of slow walking per week
- intermediate: 2.5-8.6 MET hours per week; about 1-2 hours of moderate exercise per week
- moderate: 8.6-18 MET hours per week; about 3-4 hours of moderate exercise per week
- high: more than 18 MET hours per week; about 5 hours of moderate exercise per week
MET stands for “metabolic equivalent of task.” It’s a measure of the energy used or calories burned during physical activity. One MET is the amount of energy you use while sitting quietly.
The researchers then looked to see how many of the women had heart problems in the 12 years after being diagnosed with breast cancer.
Heart problems included heart attack, chest pain, stroke, build-up of plaque in the arteries away from the heart, and dying from heart failure.
After taking into account how old the women were, the researchers found that women who exercised at intermediate, moderate, and high levels before being diagnosed with breast cancer were less likely to have heart problems compared to women who exercised at the lowest level:
- intermediate exercisers were 23% less likely to have heart problems
- moderate exercisers were 25% less likely to have heart problems
- high exercisers were 41% less likely to have heart problems
Women who exercised at intermediate, moderate, and high levels before being diagnosed with breast cancer also were less likely to be diagnosed with coronary heart disease, a build-up of plaque in the arteries in the heart, compared to women who exercised at the lowest level:
- intermediate exercisers were 41% less likely to have coronary heart disease
- moderate exercisers were 55% less likely to have coronary heart disease
- high exercisers were 60% less likely to have coronary heart disease
While this study only looked for an association between exercise before diagnosis and a lower risk of heart problems in women after treatment, 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 5 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.