There is still limited evidence on ways to prevent cognitive decline in later life, which results from structural changes in the brain, the causes of which are poorly understood. Physical and other leisure activities have been proposed as ways to preserve cognitive functioning, but it is difficult to determine whether participation in such activities is a cause of, or a result of, cognitive wellbeing. A recent article in Neurology supports the hypothesis that physical activity may have a neuroprotective effect. In the study, physical activity at the age of 70 was associated with less brain atrophy and fewer white matter lesions at the age of 73, even after factoring in a variety of medical, cognitive and social covariates.
The study used longitudinal data from 691 participants in the Lothian Birth Cohort 1936 study, a longitudinal study in Scotland. Data available from participants included IQ test scores taken at age 11, self-reported data on medical history and activity level at the age of 70, and structural brain biomarkers captured via an MRI scan taken at the age of 73. Participants also were administered the Mini Mental State Examination (MMSE), a screening tool for dementia, at 70.
The activity questionnaire at the age of 70 asked participants to rate their physical activity on a six-point scale, and to rate their participation in 15 different social and intellectual activities. In their analysis, the researchers examined the relationship between these activities at the age of 70 and the neurological signs observed three years later. The other variables (such as the social and medical variables and the earlier-life IQ score, which was used as an estimate of baseline cognitive ability), were included in the statistical analysis to see if any relationships between activity and neurology were better explained by these other factors. Even when considering the other related variables, higher levels of physical activity at the age of 70 were associated with reduced neurological atrophy at 73. The other leisure and intellectual activities were not associated with any of the biomarkers when factoring in the related variables.
The authors note that physical activity may serve as a proxy for better overall health, which would mean that physical activity does not necessarily lead to improved neurological health. It is also worth noting that no cognitive tests were reported at the later time point, so it is unclear whether the neurologically protective effects also had a positive relationship with cognitive ability; however, the brain biomarkers examined in the study are strongly associated with mental function. The hypothesis that physical activity has some neurologically protective role is supported by other evidence on, for example, the relationship between hypertension and cognitive decline that has been established by other research. These findings suggest that physical activity may be an important aspect of interventions to protect cognitive function in later life.