Aerobic exercise may improve cognitive function for women who undergo chemotherapy

ByJosh Friedman

Fact checked byMindy Valcarcel, MS

Key takeaways:

Women with breast cancer who followed an aerobic exercise regimen during chemotherapy self-reported improved cognitive function.
Objectively measured neuropsychology tests did not demonstrate benefit.

Women with breast cancer who began an aerobic exercise program at the start of chemotherapy self-reported improved cognitive function and quality of life, according to results of a randomized trial.

However, objective assessment with neuropsychology tests did not show improvement.

Walking — Woman with breast cancer who began an aerobic exercise program at the start of chemotherapy self-reported improved cognitive function and quality of life. *Image: Adobe Stock.*

“Our findings strengthen the case for making exercise assessment, recommendation and referral a routine part of cancer care,” researcher Jennifer Brunet, PhD, professor at University of Ottawa, said in a press release. “This may help empower women living with and beyond cancer to actively manage both their physical and mental health during and after treatment.”

Background and methods

Approximately 75% of women with breast cancer who received chemotherapy have reported cognitive impairment, according to study background.

This may include trouble remembering, concentrating or thinking about the short or long term, as well as worsening working memory, processing speed, and spatial, verbal and language abilities.

Prior research showed aerobic exercise can help older adults improve cognitive function or stop its decline, but whether this held true for women with breast cancer had not been established.

Brunet and colleagues conducted a two-center trial that included 57 women (mean age, 48.8 years, range, 29-70; 72.2% white) with stage I to stage III breast cancer who had not yet started chemotherapy.

Researchers randomly assigned 28 women to aerobic exercise with chemotherapy. Women in this cohort had three aerobic sessions weekly (20 to 40 minutes each) for the duration of their 12- to 24-week treatment.

The other 29 women received standard care with aerobic exercise after treatment completion.

Objective cognitive function, measured through 13 tests before and after the intervention, served as the primary endpoint. Self-reported outcomes served as the secondary endpoint.

Results and next steps

The exercise arm attended a mean 33.8 of 43.3 supervised sessions that had been prescribed (median attendance, 87.9%).

On average, 64.6% of sessions reached prescribed duration and intensity levels.

Researchers observed no significant objective improvement in cognitive function in the exercise cohort with the exception of one test (Trail Making Test part B; mean difference = 0.45; 95% CI, 0.86 to 0.04).

However, women in the exercise group demonstrated improvement compared with the control group in four self-reported measurements — perceived cognitive impairment (mean difference = 11.4; 95% CI, 5-17.8), perceived cognitive abilities (mean difference = 4.7; 95% CI, 2-7.4), total FACT-Cog score (mean difference = 18.4; 95% CI, 7.8-29) and perceived cognitive function (mean difference = 3.3; 95% CI, 0.9-5.8).

Researchers described methodological and conceptual factors that could have led to the conflicting results.

“[Methodologically], the neuropsychological tests reflect patients’ abilities to perform during the testing session, and could be influenced by any number of personal or environmental factors occurring at that time,” they wrote. “Conceptually, performance on neuropsychological tests is an indicator of a person’s ability to perform in a structured optimal‐performance setting, whereas self‐report considers patients’ reports of success in everyday performance or real‐world functioning, and their reports may be influenced by other factors affecting their functioning and quality of life.”

Researchers acknowledged study limitations, including the small sample size and adjustments for the COVID-19 pandemic.

“We advocate for collaboration across various sectors — academic, health care, fitness and community — to develop exercise programs specifically designed for women with breast cancer,” Brunet said. “These programs should be easy to adopt and implement widely, helping to make the benefits of exercise more accessible to all women facing the challenges of cancer treatment and recovery.”