Exercise Reduces Risk of Functional, Heart Problems Related to Chemotherapy
Women receiving anthracycline chemotherapy for early-stage breast cancer who exercised three or four days a week for a year had a lower risk of functional problems and better cardiovascular health than women who didn’t exercise, according to an Australian study.
The research was published online on Nov. 7, 2022, by the journal Circulation. Read the abstract of “Exercise for the Prevention of Anthracycline-induced Functional Disability and Cardiac Dysfunction: The BREeast Cancer Randomized EXercise InTervention (BREXIT) Study.”
About anthracycline chemotherapy medicines
There are five types of anthracycline chemotherapy medicines used to treat breast cancer:
Adriamycin (chemical name: doxorubicin)
Ellence (chemical name: epirubicin)
Doxil (chemical name: liposomal doxorubicin)
daunorubicin (brand names: Cerubidine, DaunoXome)
mitoxantrone (brand name: Novantrone)
Anthracyclines work by damaging a cancer cell’s genes and interfering with its reproduction.
Like all chemotherapy medicines, anthracyclines may cause side effects, including heart damage, which can lead to heart failure. Anthracyclines also can cause fatigue and muscle loss, both of which can reduce a person’s ability to do basic activities, including bathing, getting dressed, and going to appointments.
Exercise important during breast cancer treatment
An October 2022 study found that people who started an exercise program while receiving chemotherapy had less severe side effects and got back to regular physical functioning faster than people who started exercising after completing chemotherapy.
In May 2022, the American Society of Clinical Oncology (ASCO) published guidelines on exercise, diet, and weight management during breast cancer treatment — basically making exercise a part of breast cancer care.
A study of more than 1,500 U.S. cancer survivors also showed how important it is to exercise after you complete breast cancer treatment. Survivors who didn’t exercise and sat most of the day were more likely to die from cancer or other causes than people who sat less and were more active.
About the study
This study, called BREXIT, included 102 Australian women diagnosed with stage I, stage II, or stage III breast cancer. All the women were receiving Adriamycin and Cytoxan (chemical name: cyclophosphamide) (AC) chemotherapy.
The women in the study had an average age of 51 and:
about 89% were white, and 9% were Asian
51% followed the recommended 150 minutes or more a week of moderate or vigorous exercise before being diagnosed with breast cancer
60% were diagnosed with hormone receptor-positive breast cancer
64% received chemotherapy before surgery (called neoadjuvant chemotherapy by doctors)
The researchers randomly split the women into two groups:
52 women were in the exercise group
50 women were in the usual care group
The women in the exercise group did three or four sessions a week of structured aerobic and resistance exercise for 12 months. Trainers supervised the exercise sessions for the first three months and the intensity of the exercise was about 5% lower in the week after the women received chemotherapy. The women then did partially supervised exercise for 14 weeks, and then did a 26-week maintenance program at home or at a community health or fitness center.
The women in the usual care group were given information on how to be physically active during treatment.
The researchers assessed the women’s fitness and functioning three times during the study:
at the beginning of the study
four months after completing chemotherapy
12 months after the study started
To assess fitness and functioning, the researchers measured the women’s peak oxygen uptake (VO2 peak) while they were walking on a treadmill on an incline.
If a person has a VO2 peak of 18 or lower, they’re considered to have problems functioning because a VO2 peak of 18 is considered the minimum requirement to complete daily living activities.
VO2 peak is also considered a good predictor of heart failure.
From the beginning of the study to four months after the women completed chemotherapy:
VO2 peak decreased by 6% in women in the exercise group
VO2 peak decreased by 13% in women in the usual care group
Twelve months after the study started:
VO2 peak was 7% lower than it was at the beginning of the study in women in the usual care group
VO2 peak was 9% higher than it was at the beginning of the study in the women in the exercise group
“We showed that an individualized and structured 12-month [exercise] program provides marked benefits on VO2 peak and cardiac function that, among those who adhere, translates into a reduced risk of functional disability,” the researchers concluded. “Taken together, the magnitude and consistency of benefit from [exercise] across functional, exercise imaging, and biochemical measures provides the strongest evidence to date for recommending exercise to all [breast cancer] patients undergoing cardiotoxic chemotherapy.”
What this means for you
The results of this study offer more evidence about the importance of exercise for people who’ve been diagnosed with breast cancer.
Exercise can help you:
maintain fitness
keep muscle mass
ease fatigue
lower your risk of functional problems
improve your quality of life
reduce your risk of heart disease
maintain a healthy weight
And if that’s not enough, a November 2022 study found that even moderate exercise, such as fast walking or easy cycling can reduce the risk of dying from breast cancer.
Still, if you’re currently receiving treatment, finding the motivation and time to exercise nearly every day can be tough, especially when you have to balance it with all the other things you have to do.
Starting slowing and then gradually increasing the time and intensity you exercise can help, especially if you’ve never exercised before. Walking for 15 to 20 minutes a day can be a good way to start. Slow bike riding or gentle stretching are also good options for beginners.
Walking or doing another type of exercise with a friend can give you the motivation you need to carve out some time to be active each day. Plus, you can socialize at the same time.
It’s never too late to get moving. And once you start, keep at it!
Learn more about exercise.
— Last updated on February 22, 2023 at 4:31 PM