Aerobic Exercise May Improve Self-Reported Cognitive Function in Breast Cancer

The use of aerobic exercise demonstrated improved self-reported cognitive function and its impact on quality of life for woman initiating chemotherapy for breast cancer; however, this intervention did not result in significant differences in objective cognitive function postintervention after chemotherapy completion.

According to study findings published in Cancer, “When considered alongside existing evidence, improved self‐reported cognitive function adds further weight to the call to action on making exercise assessment, prescription and referral a medical standard of care,” study authors wrote.

After 12 to 24 weeks of the intervention, four out of six self-reported cognitive function outcomes showed significant differences favoring the aerobic exercise group. These improvements included perceived cognitive impairment, perceived cognitive ability, overall (i.e., total) perceived cognitive function and associated quality of life. This suggests that regular aerobic exercise is influential in preserving or improving these self-reported cognitive function and quality of life outcomes, as mentioned in the study. No significant differences between groups were found for measured cognitive ability outcomes during postintervention after accounting for multiple tests.

“These results do not support the hypothesis that exercise improves cognitive performance in key domains affected by chemotherapy (e.g., verbal/visual memory, attention, working memory, processing speed, executive function and psychomotor performance),” study authors wrote. “However, the intervention resulted in greater improvements in self‐reported cognitive function and its impact on [quality of life] for the [exercise intervention] group compared to the [usual care] group.”

Furthermore, as reported by patients, side effects were not attributable to the exercise intervention.

The exercise intervention involved progressive aerobic training during chemotherapy, initially supervised in-person but switched to unsupervised sessions due to COVID-19 restrictions, with remote support via email, text and phone calls. The intervention lasted 12 to 24 weeks, matching the chemotherapy regimen. Patients received three personalized sessions weekly, targeting specific heart rate and power output zones.

Sessions lasted 20 to 40 minutes and were led by certified exercise professionals. Patients used treadmills, stationary bikes and ellipticals and were encouraged to vary their exercise modes to prevent injuries. Heart rate monitors tracked exercise intensity, and if chemotherapy side effects hindered reaching target zones, patients were advised to exercise at a manageable perceived exertion level.

The usual care group served as a wait-list control condition, which involved no active treatment and followed the standard care protocol at the participating site. Participants in the usual care group were advised to continue their normal exercise routine without any restrictions.

Once chemotherapy was completed, the usual care group received the same exercise program as the exercise group, although the duration was limited to 12 weeks. Exercise prescriptions for patients were tailored based on their results from the post-chemotherapy cardiopulmonary exercise test (CPET).

Of note, patients who were limited in their ability to reach their target heart rate zone by the side effects of chemotherapy were encouraged to work at the rating of perceived exertion associated with heart rate zone via the 6 to 20 Borg scale.

The Borg scale measures exertion on a range from 6 (no exertion) to 20 (maximum effort). A rating between 12 and 14 usually indicates a moderate or somewhat hard level of intensity.

A total of 57 patients were analyzed, ages from 29 to 70, with stage 2 breast cancer. The exercise intervention group consisted of 28 patients and the usual care group consisted of 29 patients. In addition, the exercise group had a mean attendance of 33.8 supervised sessions out of an average of 43.3 prescribed total sessions.

The most common exclusion criteria were starting chemotherapy and engaging in moderate- to vigorous-intensity aerobic exercise for 150 or more minutes per week in the three months before enrollment.

Reference:

“Aerobic exercise and CogniTIVe functioning in women with breAsT cancEr (ACTIVATE): A randomized controlled trial” by Dr. Jennifer Brunet, et al., Cancer.

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