Older adults who move more, either with daily exercise or simple routine physical activity like housework, may preserve more of their memory and thinking skills, even if they have brain lesions or biomarkers linked to dementia, according to a study published in Neurology.
“Our 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,” said Aron S. Buchman, MD, Rush University Medical Center, Chicago, Illinois. “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.”
For the study, Dr. Buchman and colleagues studied 454 older adults; 191 had dementia and 263 did not. All participants were given physical exams, thinking tests, and memory tests every year for 20 years. Participants agreed to donate their brains for research upon death.
At an average of 2 years before death, researchers gave each participant an activity monitor. The wrist-worn device monitored physical activity around the clock, everything from small movements such as walking around the house to more vigorous movements like exercise routines. Researchers collected and evaluated 7 days of movement data for each participant and calculated an average daily activity score.
After death, the researchers examined the brain tissue of each participant, looking for lesions and biomarkers of dementia and Alzheimer’s disease.
The study found that higher levels of daily movement were linked to better thinking and memory skills. The researchers also found that people who had better motor skills also had better thinking and memory skills.
For every increase in physical activity by 1 standard deviation, participants were 31% less likely to develop dementia. For every increase in motor ability by 1 standard deviation, participants were 55% less likely to develop dementia.
The analysis showed that physical activity and motor abilities accounted for 8% of the difference among participant’s scores on the thinking and memory tests, according to Dr. Buchman.
The relationship between activity and test scores was consistent even when researchers adjusted for the severity of participants’ brain lesions. They also found that the relationship was consistent in participants who had dementia and those who did not.
The link between a higher level of physical activity and better thinking and memory skills was unrelated to the presence of biomarkers of Alzheimer’s disease and related disorders.
A limitation of the study was that it did not have data on how active participants were over the course of their lives, just during 1 period later in life, so it is unknown if physical activity in early life also may have played a role. Also, the study did not include the type of physical activity, so it is difficult to determine if 1 physical activity may be more beneficial than another.
“Exercise is an inexpensive way to improve health, and our study shows it may have a protective effect on the brain,” concluded Dr. Buchman. “But it is important to note that our study does not show cause and effect. It may also be possible that as people lose memory and thinking skills, they reduce their physical activity. More studies are needed to determine if moving more is truly beneficial to the brain.”