The study found breast cancer survivors who engaged in higher levels of moderate-to-vigorous physical activity appeared to experience reductions in perceived memory impairment.
These were the findings of a new study led by Northwestern University in Chicago, IL, and published in the journal Psycho-Oncology.
A surprising suggestion from the results was that memory problems appear to be linked to high stress in breast cancer survivors, rather than specifically as a result of chemotherapy or radiation treatment.
Lead author Siobhan Phillips, assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine, says:
"We found moderate to vigorous physical activity actually benefits women psychologically and that, in turn, helps their memory."
The study involved 1,477 female breast cancer survivors recruited after their treatment had finished. The women completed surveys about their physical activity, self-efficacy, distress, fatigue, and perceived memory impairment. They completed the surveys twice: once at the start of the study and then again 6 months later.
Self-efficacy is a definition of self-confidence that psychologists use - defined as believing in one's ability to achieve goals and chosen levels of performance.
A randomly selected subgroup of 362 participants also wore accelerometers, devices that measure amount of physical activity.
Exercise indirectly influenced perceived memory impairment
The researchers found higher levels of moderate-to-vigorous physical activity were linked to reduction in perceived memory impairment - both in the overall group (based on self-reports) and in the subgroup (based on accelerometer readings).
In addition, the researchers found more physical activity was linked to higher levels of self-efficacy, and lower levels of distress and fatigue.
They say the findings support their theory that physical activity indirectly influences perceived memory impairment via exercise self-efficacy, distress and fatigue.
Moderate-to-vigorous activity includes exercise that challenges you enough to make you breathless and sweaty - for example brisk walking, cycling, jogging, and taking part in exercise classes.
Deaths from breast cancer have been falling since about 1989. The biggest drop has been in women under 50, likely due to earlier detection, increased awareness, and better treatments.
There are currently more than 2.8 million breast cancer survivors in the United States. This figure includes patients still undergoing treatment.
Men also get breast cancer, although it is about 100 times less common in males than in females. Estimates suggest about 2,600 new cases of invasive breast cancer will be diagnosed in American men in 2016, and about 440 men will die of the disease.
"Our research suggests these self-reported memory problems may be emotionally related. These women are frightened, stressed, fatigued, tapped out emotionally and have low self-confidence, which can be very mentally taxing and can lead to perceived memory problems."
Prof. Siobhan Phillips