Being physically active throughout adulthood — regardless of how intensely — was linked to higher cognition at older ages, according to a new study published in the Journal of Neurology, Neurosurgery, and Psychiatry.

How routine exercise can improve your cognition

For the study, researchers followed 1,417 participants from the 1946 British Birth Cohort, a long-running study of individuals who were born in the same week in 1946 in the United Kingdom. Of the participants, 53% were women.

The participants reported their leisure time physical activity at five time points: ages 36, 54, 53, 60-64, and 69. Physical activity was labeled as not active, moderately active (participated 1-4 times/month), or most active (participated 5 or more times/month).

To assess cognition, researchers used Addenbrooke's Cognitive Examination III (ACE-III) to evaluate participants' cognitive state, word learning tests for verbal memory, and visual search tests for processing speed.

Among the participants, 11% were physically inactive at all time points; 17% were active during one time point; 20% were active during two; 20% were active during three; 17% were active during four; and 15% were active during all five.

Overall, participants who were physically active during at least one time period had higher cognitive scores at age 69 than those were inactive during all time points.

The researchers also found that being active during more time periods was associated with higher ACE-III and word learning test scores at age 69. In particular, the largest effect was between cumulative physical activity and ACE-III score, with people who were active across all time periods seeing the most impact.

Participants who were the most physically active at any time point also had significantly higher cognitive visual search speed scores at age 69. However, the association between moderate physical activity and visual search speed was less significant.

In general, sex or APOE4 status did not significantly impact the relationship between cumulative physical activity and ACE-III scores. Although childhood cognition, socioeconomic status, education slightly reduced the overall effect size, the association between physical activity and cognition remained significant.

Commentary

"These findings have shifted our understanding as we show that the timing of being physically active across 30 years of adulthood and the intensity at certain points were not as important for maintaining good cognitive function later in life," said Sarah-Naomi James, the study's lead author from University College London.

"Instead, the results indicate that just starting to do a small amount of activity at any time across adulthood and maintaining it was linked preserved later-life cognitive function," she said. "Being physically active for as long as possible is the most optimal."

However, the researchers also noted several limitations, including the fact that there was disproportionate attrition over the years among participants who were socially disadvantaged and less healthy. Physical activity was also only measured through self-reported data.

"An outstanding question and limitation of this work is that we don't know what types of activity may confer the most benefit," James said.

"We also don't know how physical activity is linked with higher cognition and we will be further looking at potential mechanisms including links with later-life brain health, cardiovascular health, cerebral blood flow, inflammation, and neurotrophic factors," she added. (George, Medpage Today, 2/21; James et al., JNNP, 2/21)