Long-term research released online in the Journal of Neurology, Neurosurgery & Psychiatry reveals that engaging in consistent exercise, regardless of age, is associated with improved brain function later in life.
The found relationships were diminished after controlling for childhood cognitive ability, family income, and schooling, but they remained statistically significant. The chances of dementia, cognitive decline, and loss of later-in-life mental sharpness are marginally inversely correlated with levels of physical exercise. Yet, whether or not consistent physical exercise in one’s free time over one’s life span is crucial to one’s mental faculties in old age is still up for debate.
The researchers were especially interested in determining if the benefits of physical exercise occurred mostly during one or several “sensitive” times spread across the life span. To attempt to answer this question, researchers analyzed data from 1417 participants (53% female) in the 1946 British birth cohort study and compared their levels of leisure time physical activity at years 36, 43, 53, 60-64, and 69 to their performance on a battery of cognitive tests taken at age 69.
Total scores ranged from 0 to 5, with 0 representing inactivity and 5 representing extreme activity at all ages. The percentage of physically inactive individuals throughout all five measurements was 11%; 17% were active at just a single measurement; 20% were active at 2 and 3; 17% active at 4; and 15% active across all 5.
The ACE-111, a validated battery of cognitive tests that includes measures of attention, direction, verbal ability, memory, speech, and visuospatial activity, as well as measures of verbal memory and speed of processing, were used to evaluate cognitive performance in individuals at age 69.
Cardiovascular and mental well-being, as well as the presence of the APOE-4 gene, are all linked to an increased risk of cognitive decline, therefore, these were also evaluated to determine whether they moderated the observed connections. The findings demonstrated that better levels of cognitive function, verbal memory, and speed of processing at age 69 were connected with higher levels of physical activity across all 5 time periods. Scientists found that being active at any point in adulthood was associated with better cognitive performance, even if it was as little as once a month. This was true for adults of all ages and for those who were mildly and highly physically active.
Yet, the biggest link was shown for individuals who were the most physically active across the board, regardless of age. Childhood cognition, socioeconomic status, and education helped to explain the beneficial correlation between cumulative physical exercise and cognitive function in later life. When these confounding variables were accounted for, the impact size remained statistically significant, and changes in cardiovascular or mental health in old age could not account for the relationships found.
Overall, these findings support the idea that being physically active throughout adulthood is more essential than starting or stopping at any one time. The researchers recognize that there are limits to their results due to the nature of the observational study.
A disproportionate number of individuals from lower socioeconomic status dropped out of the research, and the study solely comprised White participants. The length, intensity, and consistency of exercise were also unknown.
Nonetheless, they draw the conclusion that their research lends credence to recommendations that advocate for individuals to engage in some kind of physical exercise throughout their lives, and that encouraging inactive persons to become more active at any time and motivating active adults to preserve their activity levels may have positive effects on cognitive function in old age:
Being physically active at any time in adulthood, and to any extent, is linked with higher later-life cognitive state, but lifelong maintenance of physical activity was most optimal. These relationships were partly explained by childhood cognition and education, but independent of cardiovascular and mental health and APOE-E4, suggestive of the importance of education on the lifelong impacts of physical activity.
