Adding to the growing body of evidence that physical activity has a positive impact on cognition, new research shows that these benefits may even extend to older adults with blood and brain biomarkers of Alzheimer's disease (AD) and other common age-related brain pathologies. More total daily activity and better motor abilities were each associated with a boost in cognitive reserve, investigators report.

"The research team measured levels of physical activity in study participants an average of 2 years prior to death and then examined their brain tissue after death and found that moving more may have a protective effect on the brain.

"People who moved more had better thinking and memory skills compared to those who did not move much at all. We found movement may essentially provide a reserve to help maintain thinking and memory skills when there are signs of dementia present in the brain," he added.

The study was published online January 16 in Neurology. "Lifestyle factors such as physical activity are being intensely studied as a means to maintain brain health and reduce Alzheimer disease dementia in our aging population," Buchman told Medscape Medical News.

Physical activity

To examine the potential associations between physical activity, AD, and other brain pathologies and cognition, the researchers studied 454 older adults who were participants in the Rush Memory and Aging Project (MAP).

Of these individuals, 191 had dementia, and 253 did not. For the study, all participants underwent comprehensive annual medical examinations and cognitive testing during a 20-year period. At death, autopsies were conducted on their brains.

"The researcher studied 454 brain autopsies from decedents with cognitive function, total daily physical activity derived from multi-day recordings with an activity monitor, and a motor ability score that summarized 10 supervised motor performances obtained proximate to death," said Buchman.

"They previously reported that a higher level of total daily physical activity was related to lower risk of AD dementia and a slower rate of cognitive decline in older adults. Yet, the mechanisms underlying these associations are poorly understood," he added.

One possibility is that physical activity may alter the relationship between motor function and white matter changes in older adults. "This raises the possibility that a more active lifestyle may modify the association of brain pathologies with cognition," the researchers note.

For the study, trained technicians administered 21 cognitive tests, and researchers calculated a composite global cognition score. The investigators also measured 10 motor abilities to create a global motor score.