There appears to be increasing evidence that physical activity in later life may support continued cognitive well-being. It is unclear, however, how this hypothesized effect may take place, or whether the association between the two is merely a side effect of more general well-being among healthier older adults. A recent study in Sweden identified specific cognitive skills and brain structures that were associated with physical activity in a sample of older adults, which supports the hypothesis that physical activity has specific, observable effects on cognitive health.
The study, published in the Neurobiology of Aging, was based on 331 older adults without dementia. The researchers assigned each participant to one of four groups, representing different levels of physical activity. Assignments were based on whether each participant engaged in light activity, such as walking or gardening, or hard exercise, such as running, for 30 or more minutes per week. Participants were administered a widely used test for dementia, as well as two specific cognitive tasks. In addition, participants were given magnetic resonance imaging (MRI) scans to assess for brain volume and brain structure.
The study found that participants with higher levels of physical activity performed faster on a memory test, performed better on a task of verbal fluency, and had higher overall cognitive test scores. Participants with higher levels of physical activity also had higher overall brain volumes and greater volumes of white matter in the brain, as well as higher grey matter volume in an area of the brain associated with early Alzheimer’s Disease. These findings suggest that it is plausible that physical activity may help improve or retain brain function.
The authors caution that no conclusions about the causal relationship between physical activity and brain health can be drawn based on their cross-sectional data (that is, data collected at one point in time); it remains uncertain whether, within this sample of participants, activity contributed to better brain health, or whether higher cognitive function led to greater physical activity. The findings are, however, consistent with the emerging hypothesis that physical activity has specific, tangible contributions to brain health.