- Older community-dwelling adults who had a higher level of total daily activity had better cognition even after accounting for brain pathologies.
Why this matters
- Mechanism whereby physical activity is protective is unclear.
- Independent, additive predictors of better cognition in full cohort:
- Higher level of total daily activity (estimate, 0.148; P=.003).
- Better motor abilities (estimate, 0.283; P<.001>
- Associations still significant when:
- Terms for Alzheimer’s disease, 9 other common age-related brain pathologies added.
- Individuals with poor cognition or dementia excluded.
- Among individuals without dementia, predictors of better cognition:
- Higher level of total daily physical activity (estimate, 0.069; P=.030).
- Better motor abilities (estimate, 0.118; P=.002).
- Among individuals with dementia, predictor of better cognition:
- Better motor abilities (estimate, 0.200; P=.006).
- In an editorial, Dr. James A. Mortimer and Dr. Yaakov Stern write, "Although important questions remain, currently available data suggest that promotion of an active lifestyle in late as well as early life that includes regular physical activity and exercise may be beneficial in reducing the risk of dementia, both through increases in reserve and reduction of Alzheimer neuropathology."
- Cohort study of 454 community-dwelling older adults (42.1% with dementia) who died (at a mean age of 90.6 years) and underwent brain autopsy (Memory and Aging Project).
- Physical activity ascertained from continuous multiday actigraphy recordings.
- Main outcome: global cognitive score (summary of 19 cognitive tests) proximate to death.
- Funding: NIH; others.
- Cross-sectional analyses.
- Activity over lifespan unknown.
- Only selected brain pathologies assessed.
- Types of activity not captured.