Exercise helped reduce the risk of heart problems in women receiving treatment for breast cancer, according to a Dutch study.

The research was published in the June 2022 issue of the journal JACC: CardioOncology. Read “Physical Activity and Cardiac Function in Long-Term Breast Cancer Survivors: A Cross-Sectional Study.”

Heart problems can be long-term side effects of a number of breast cancer treatments, particularly:

anthracycline chemotherapy medicines, which include Adriamycin (chemical name: doxorubicin), daunorubicin, and Ellence (chemical name: epirubicin)

left-side radiation therapy, because the heart is on the left side

Research shows that seven or more years after completing breast cancer treatment, women have nearly twice the risk of dying from heart problems than women with no history of breast cancer.

There are several ways doctors measure how well your heart functions. One of the oldest and most commonly used measures is left ventricular ejection fraction (LVEF), which is a percentage of how much blood the left ventricle pumps out with each heartbeat. An LVEF of 60% means that 60% of the total amount of blood in the left ventricle is pushed out with each heartbeat. A normal LVEF is between 50% and 70%.

A newer measure is global longitudinal strain (GLS), which measures the change in length of the opposing layers of cardiac muscle fibers in the left ventricle as the heart beats. Myocardial fibers make up the muscular layer of the heart. GLS varies with age and sex, and is expressed as a negative number. Research suggests normal GLS ranges from approximately -18% to -22%.

Because LVEF measurements can vary by image quality, GLS is becoming a more popular way to measure heart function.

Studies show that exercise reduces the risk of heart problems in people with no history of cancer. But not much research has been done on exercise and heart disease risk in people with a history of cancer. In this study, the researchers wanted to see if exercise could reduce the risk of heart problems in people who have received treatment for breast cancer.

The researchers analyzed information from a study called HARBOR (Identifying Subgroups With High Cardiovascular Risk in Breast Cancer Survivors). This Dutch study included 569 women between the ages of 40 and 50 who received treatment for stage I to stage III breast cancer between 2002 and 2007 or 2008 and 2012:

42.6% received left-side radiation, and 45.8% received right-side radiation

none of the women had a history of heart disease before being diagnosed with breast cancer

The researchers assessed the function of each woman’s heart in a number of ways, including:

2D echocardiograms (an ultrasound that checks the heart’s structure and function)

All the women completed a questionnaire that asked about their physical activity during the previous year. The questionnaire asked about both work and recreational activities:

Inactive women did no exercise and mostly sat at work.

Moderately inactive women exercised up to 3.5 hours a week or did no exercise and stood most of the time at work or did manual labor.

Moderately active women exercised from 3.5 to seven hours a week; if they exercised for 3.5 hours a week or less, they stood most of the time at work.

exercised more than seven hours a week

exercised from 3.5 to seven hours a week and stood most of the time at work

exercised up to 3.5 hours a week and did manual labor

didn’t exercise but did heavy manual labor

Most of the women said they sat most of the time at work.

This analysis included information from 559 of the women in the HARBOR study. The researchers didn’t include 10 women in their analysis because there was no physical activity information for them.

5% of the women were considered inactive

22.7% of the women were considered moderately inactive

27.5% of the women were considered moderately active

44.7% of the women were considered active

37.7% of the women had high blood pressure

31.5% of the women had high cholesterol

6.8% of the women had diabetes

45.3% of the women were former smokers, and 14.5% were current smokers

High blood pressure, high cholesterol, diabetes, and smoking are all risk factors for heart disease.

About 66% of the inactive women were diagnosed five to seven years earlier. The women in the other three activity groups were diagnosed more than 10 years earlier.

The researchers looked for links between physical activity and heart function.

They found that GLS measurements were the best for active women. GLS was:

So compared with inactive women, moderately active women had a 35% lower risk of an abnormal GLS and active women had a 39% lower risk of an abnormal GLS. This was true whether or not the women:

had any of the four measured risk factors for heart disease

received breast cancer treatments known to cause heart problems

LVEF was about the same and in normal range for all four activity groups.

“Considering that subclinical cardiac dysfunction (i.e., impaired GLS) may precede adverse cardiovascular events, these results suggest that efforts to increase physical activity levels by, for example, offering a physical activity program, may contribute to reducing cardiovascular morbidity in breast cancer survivors,” the researchers wrote.

In an accompanying editorial, Edith Pituskin, RN, MN(NP), PhD, of the University of Alberta in Edmonton, and colleagues, wrote: “With technical advances in echocardiography, GLS can be reliably assessed and is recognized as superior to LVEF for detecting subclinical changes [in heart function]. GLS reflects subendocardial fiber injury and detects subtle changes in wall motion despite normal LVEF.

“[It] is worth reflecting that traditional exposures, namely anthracyclines and left-sided radiotherapy, did not influence the . . . results,” they added.

If you’ve received breast cancer treatment, heart problems are a possible long-term side effect.

But this study offers some very good news: Exercise can help reduce the risk of heart problems, even if you received treatments known to cause heart problems, such as anthracycline chemotherapy, left-side radiation, and Herceptin.

Exercise is so important that it’s now considered part of breast cancer care. The American Society of Clinical Oncology (ASCO) released guidelines on exercise, diet, and weight management during breast cancer treatment in May 2022.

Exercise remains important even after breast cancer treatment is completed. A study of more than 1,500 U.S. cancer survivors found that survivors who didn’t exercise and sat most of the day were more likely to die from cancer or another cause than people who sat less and were more active.

Still, we know that if you’re recovering from breast cancer or still receiving treatment — and are busy with work, household chores, and family matters — finding time to exercise almost every day can seem impossible.

It makes sense to start slowly, especially if you’ve never exercised before. You may want to start by walking for 15 to 20 minutes a day and gradually increasing the amount of time you walk. Slow bike riding or gentle stretching is also a good way to start.

You may want to walk with a friend. People are more likely to stick with a routine when they exercise with a friend — plus, you can socialize at the same time.

No matter how old you are, it’s never too late to get moving. And once you start, keep at it!

To talk with others about the benefits of exercise and to share exercise tips and get encouragement, join the conversation on Working on Your Fitness in our community.

Written by: Jamie DePolo , senior editor

— Last updated on July 6, 2022, 6:58 PM

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