Older people who would like to stay sharp can take one simple step: keep moving! Research from Rush University Medical Center suggests that physical activity can reduce elders’ risk of dementia (Buchman et al, Neurology, Feb. 19, 2019). In fact, it is one of the few strategies that can reduce the risk of dementia. Keep reading to learn about the study from Rush and other studies looking at how activity–including intellectual and social engagement–helps the brain.
How Was the Rush Research on Physical Activity and Cognitive Function Conducted?
The investigators examined 454 older individuals every year for as long as 20 years. The volunteers took cognitive tests and had annual physical exams. They also agreed to donate their brains for examination upon their deaths.
It is more complicated to measure physical activity, other than relying on what people say they are doing. (That doesn’t always correspond well to what they actually do.) To determine the volunteers’ activity levels, each participant wore an accelerometer for seven days during the study. This wristwatch-like device measures all movements. These may range from small actions such as walking from one room to another to much larger actions such as a vigorous exercise routine. In addition, the volunteers completed 10 supervised motor performance tests as part of the testing regimen.
What Was the Relationship Between Physical Activity and Dementia?
Some of the study subjects had dementia, while the others did not. The accelerometer picked up differences between these two groups. Those with dementia made an average of 130,000 movements daily, as counted by the accelerometer. That may sound like a lot, but the people who were in better cognitive shape made an average of 180,000 movements daily. Overall, people with better motor skills also scored better on measures of memory and thinking.
Volunteers who moved more during the day were more likely to be thinking clearly and remembering things better. Physical activity and motor skills accounted for 8 percent of the differences in cognitive test scores. Brain autopsies showed that even people with signs of Alzheimer disease did better than expected if they maintained strong physical activity to the end of their lives.
The scientists concluded:
“Physical activity in older adults may provide cognitive reserve to maintain function independent of the accumulation of diverse brain pathologies. Further studies are needed to identify the molecular mechanisms underlying this potential reserve and to ensure the causal effects of physical activity.”
This is not the first study to demonstrate the cognitive benefits of physical activity. A recent study showed that seniors in an active exercise program improved their executive function. Of course, there is also the more immediate reward: taking time to play just makes you feel good!
How Does Regular Exercise Affect the Brain?
Another study published in the journal Neurology may have uncovered a mechanism to explain how physical activity affects the brain (Neurology, April 13, 2022). The researchers recruited 134 older people without cognitive difficulties and scanned their brains. Those who reported more physical activity also had more gray matter. They also had better glucose metabolism in their brain tissue. In addition, those who exercised regularly had lower body mass indices (BMI) and insulin levels.
The lead author notes that
“Maintaining a lower BMI through physical activity could help prevent disturbed insulin metabolism that is often seen in aging, thus promoting brain health.”
Staying Active Can Help Ward Off Cognitive Decline:
You may have noted the term “cognitive reserve” in one of the quotes above. Two recent studies, both from the UK, suggest that staying engaged socially and intellectually along with moving the body can help reduce our chances of cognitive decline.
The 1946 Birth Cohort:
One of these studies focused on people born in the UK in 1946 (Neurology, August 3, 2022). The researchers had data on 1,184 participants at numerous times in their lives. First, they had cognitive tests from 1954, when the participants were eight years old. Presumably these were similar to the IQ tests that some of us took during childhood in the US.
The scientists also created a “cognitive reserve index” from three measures during adulthood: educational attainment by age 26, leisure activity participation at age 43, and occupation(s) up to 53. Two additional measures allowed them to test cognitive decline in adulthood. In one, they measured reading skill at 53. In the final tests, they assessed the volunteers’ APOE genetic status, since this is known to affect the risk of Alzheimer disease. And finally, they conducted tests called Addenbrooke’s Cognitive Examination.
What they found was interesting: people who’d had high scores in childhood also tended to do better at age 69. However, for people who scored well on their adult reading test and their measures of cognitive reserve, the childhood intelligence scores were unrelated to the 69-year-old scores.
One of the study’s authors summarized the results:
“…taking part in an intellectually, socially and physically active lifestyle may help ward off cognitive decline and dementia.”
The UK Biobank Study:
Another recently published study recruited 501,376 participants from the UK Biobank between 2006 and 2010 (Neurology, July 27, 2022). The scientists collected data on mental and physical activity from the volunteers at that time. (Participants’ mean age then was 56.) These investigators also knew the subjects’ APOE status, because the biobank is a repository for genetic material.
After more than ten years of follow-up, just over one percent of the volunteers had developed dementia. Analysis revealed that those who frequently engaged in vigorous physical activity were 35 percent less likely to have it. Housework and visits with friends and family also reduced the risk for dementia significantly. These were independent of the role of the APOE gene.
According to one of the study authors, Dr. Huan Song:
“By engaging more frequently in healthy physical and mental activities, people may reduce their risk of dementia, irrespective of their inherited genetic susceptibility.”