Physical Activity and Cognitive Functioning

Evidence from Animal Models

Research with healthy older rodents found that wheel running offset the cognitive declines associated with aging (e.g., the ability to learn and remember). Further, there is evidence from animal models to suggest that exercise may spare cognitive and motor deficits associated with a number of neurodegenerative diseases, including Parkinson's, Alzheimer's, and Huntington's disease. In large part, these improvements in animal models have been associated with exercise-induced increases in new blood vessel growth in the brain (i.e., angiogenesis). It has been suggested that one function of angiogenesis is to provide the brain with more nutrients and trophic factors necessary for neuroprotection, cell proliferation, and learning and memory. Additionally, exercise has been associated with the development of new neurons in rodents (i.e., neurogenesis), which is accompanied by enhanced spatial learning and memory performance. In summary, there is ample evidence to suggest that exercise has a significant effect on cognition and brain properties in rodents, and this work has provided the impetus for an increasing number of studies in humans.

Epidemiological Evidence

Epidemiological studies have shown that many lifestyle factors, including education, physical activity, fitness level, and self-efficacy, affect cognition as we age. Cross-sectional studies also strongly support the link between exercise and cognition in older adults. These studies have demonstrated that those individuals who are more physically active perform better on cognitive tasks examining reasoning, working memory, and executive functioning. Additionally, these studies have shown that physically active older individuals perform much like younger adults on tests of executive function when compared with their non–physically active counterparts. High-fitness older adults demonstrate faster neuroelectric responses in a task-switching paradigm than low-fitness adults, suggesting that they are able to more rapidly process information under challenging circumstances. In addition, a recent study using magnetic resonance imaging (MRI) found older fit adults to have significantly greater white and gray matter brain volume than less fit older adults.

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