Even though factoring in childhood cognitive ability, household income and education weakened the observed associations, the findings remained statistically significant.
Physical activity is moderately associated with a reduced risk of dementia, cognitive decline, and later-life mental acuity. But it is not known whether the timing, frequency, or maintenance of leisure-time physical activity may be important for later-life cognitive abilities.
The researchers were particularly keen to find out whether physical activity may be most beneficial at specific ‘sensitive’ periods throughout life or at multiple time periods.
Can exercise improve brain function even as we age?
To try and find out, they looked at the strength of associations between a series of cognitive tests at age 69 and leisure time in 1417 people (53%) at ages 36, 43, 53, 60–64, and 69. Reported physical activity over time. women) participating in the 1946 British Birth Cohort Study.
Physical activity levels were classified as follows: inactive; Moderately active (1-4 times/month); Most active (5 or more times/month), and all 5 assessments were summed to create a total score ranging from 0 (inactive at all ages) to 5 (active at all ages).
Some 11% of participants were physically inactive at all 5 time points; 17% were active in one; 20% were active on days two and three; 17% were active on all four and 15% on all five.
Cognitive performance at age 69 was assessed using the validated ACE-111, which tests attention and orientation, verbal fluency, memory, language, and visuospatial function, as well as verbal memory (word learning test) and by testing processing speed (visual search speed).
Factors associated with increased risk of cognitive decline—cardiovascular and mental health, and carriage of the APOE-ε4 gene—were also assessed to see whether these modified any observed associations.
active body = healthy mind
The analysis of the results showed that Being physically active at all 5 time points was associated with higher cognitive performance, verbal memory, and processing speed at age 69.
Effect sizes were similar across all adult ages, and for those who were moderately and most physically active,” suggesting that Being physically active at any time in adulthood, even if participating at least once per month, is associated with higher cognitionwrite the researchers.
But the strongest associations were seen for continued cumulative physical activity and later life cognition, and for those who were most physically active at all ages.
The positive association between cumulative physical activity and later life cognitive performance was partially explained by childhood cognition, socioeconomic status, and education.
But the effect remained significant when these were included, and the associations were not explained by differences in cardiovascular or mental health in later life.
“Together, these results suggest that the initiation and maintenance of physical activity in adulthood may be more important than the timing … or the frequency of physical activity in a specific period,” say the researchers.
This is an observational study, and as such, cannot establish causation, and the researchers acknowledge the various limitations of their findings.
The study included only white participants and had a disproportionately high rate among the socially disadvantaged. No information was available on exercise intensity, duration or adherence.
But they nevertheless conclude: “Our findings support guidelines recommending participation in any physical activity in adulthood and provide evidence that encourages inactive adults to become more active at any time, and encourage previously active adults to maintain activity may confer benefits on later-life cognition.”Life Style