Chemotherapy drugs may damage cancer patients' hearts and increase their risk of heart disease, however, exercise during treatment may protect against this increased risk, new research suggests.
Adult cancer patients who participated in an exercise program while undergoing chemotherapy experienced a boost in their fitness level, according to the study. Those who did not exercise during chemotherapy experienced a decline in fitness. A low fitness level, as measured by the amount of oxygen the body uses during exercise, is an indicator of future cardiovascular disease risk.
"Our data suggest that women with breast cancer shouldn't wait to exercise [until] after the completion of therapy," said study researcher Lee W. Jones, scientific director of Duke University's Center for Cancer Survivorship.
The study was presented Nov. 4 at the American Institute of Cancer Research meeting in Washington, D.C.
Until recently, it was thought that exercise could be harmful to cancer patients. The new findings add to a growing body of evidence showing there are benefits to exercise for cancer patients, including better quality of life and possibly a reduced risk of death. [See 4 Kinds of Exercise That Help Cancer Patients.]
Exercise can also provide cancer patients with a sense of control in a situation that often seems out of their hands.
"[It's] a very empowering intervention," Jones said. "They can take some control over their symptoms, and, possibly, their long-term prognosis," Jones said.
Exercise during chemotherapy
Chemotherapy, along with the other cancer treatments, can damage the patient's heart , blood vessels, lungs and muscles. Studies show such treatments together can increase breast cancer survivors' risk of heart disease by 10 percent to 30 percent, Jones said.
Exercise may help make your organs healthy and more resistant to the toxic effects of these therapies, Jones said.
The new study involved 20 cancer patients who were undergoing chemotherapy. Patients were randomly assigned to two groups: one group biked three times a week during a supervised exercise program, while the other did not exercise.
After 12 weeks, the fitness levels of those in the non-exercise group declined 10 percent, while those of the exercise group increased 12 percent.
The study was small and more research is needed to confirm the results. In addition, future research should investigate how the timing of exercise — before, during or after diagnosis — affects patients' results.
How to exercise
Patients should exercise during chemotherapy only if they feel they have the capacity to do so, Jones said. And before beginning an exercise regimen, patients should consult with their oncologist.
The best exercise "is one that you'll do," Jones said, so patients should pick an exercise that they like, such as walking, biking or swimming. People who have not previously been regular exercisers should start gradually, Jones said.
"Just because you're getting treatment doesn't mean you can't exercise," Jones said.
Pass it on: Exercise during chemotherapy may be beneficial for patients' hearts.
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Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.