Evidence for the importance of physical activity in keeping and potentially improving cognitive function throughout life was found in an open-access literature review in Psychonomic Bulletin & Review by Hayley Guiney and Liana Machado from the University of Otago, New Zealand.
Cognitive functions such as task switching, selective attention, and working memory appear to benefit from aerobic exercise. Studies in older adults reviewed by the authors consistently found that fitter individuals scored better in mental tests than their unfit peers.
Scores in mental tests improved in participants who were assigned to an aerobic exercise regimen compared to those assigned to stretch and tone classes.
Exercise has been found to positively affect mental tasks relating to activities such as driving, an activity where age is often seen as a limiting factor.
MRI studies of aging have shown that, as compared with unfit, highly fit older adults exhibit less age-related atrophy in the prefrontal and temporal cortices; preserved neural tracts connecting the prefrontal cortex to other regions of the brain; superior white matter integrity in the corpus callosum; greater gray matter density in the frontal, temporal, and parietal cortices; and greater hippocampal volumes.
Physically active older adults have both higher circulating neurotrophin levels and gray matter volumes in the prefrontal and cingulate cortex.
These results were not replicated in children or young adults, except for memory tasks. Both the updating of working memory and the volume of information which could be held was also better in young fitter individuals or those put on an aerobic exercise regime. “Although the evidence to date supports a wider range of executive functions benefiting from regular exercise in older adults, the relative lack of supportive evidence in young adults and children may, in part, reflect a poverty of studies, especially controlled trials, in these age groups,” the authors suggest.