Physical activity has been associated with many healthy benefits including reductions in cardiovascular disease, colon and breast cancer, diabetes and obesity. Despite these robust effects, 75% of adults in the United States do not meet currently recommended guidelines for exercise. Estimates indicate that such inactivity was associated with health costs of $76 billion dollars in the United States in 2000. In addition to the physical and economic impact of a sedentary lifestyle, there is an emerging body of scientific research suggesting a connection between exercise and improved brain health and function. Although most of the investigations have evaluated aging humans, some recent studies have investigated the impact of physical activity on cognitive performance in children.

A meta-analysis of studies in school-age children found a positive relationship between level of activity and a number of measures of cognition (perceptual skills, IQ, achievement, verbal tests, math tests, memory, developmental level and academic readiness).

Recently, primarily due to the importance placed on standardized testing, many schools have reduced or done away with physical education (PE) requirements in an effort to ostensibly increase available time for scholastic pursuits. At odds with this mindset are recent studies indicating that performance on standardized tests of mathematics and reading were related to physical fitness scores. Fitness is linked to functioning of the fronto-parietal parts of the brain so it is not surprising that both math and reading elicit activation in this same neural network.

In adults, results from similar types of meta-analyses investigating exercise and cognitive processing reveal several key findings. First, physical activity has a beneficial impact on cognition. Second, chronic activity improves function in both normal adults and patients with early signs of Alzheimer disease. Third, exercise positively affects a broad range of cognitive variables. Fourth, the degree of improvement varies among mental modalities with some (such as executive control processes including scheduling, working memory, multi-tasking and dealing with ambiguity) showing disproportionately larger effects. This is exciting since these executive functions, and the brain regions that mediate them, tend to show age-related deterioration and these findings suggest that such changes may be amenable to intervention.

Consistent with these conclusions, MRI (Magnetic Resonance Imaging) studies have been used to asses the effects of fitness on brain anatomy. Typical findings reveal that higher levels of activity are associated with larger volumes of grey matter in the prefrontal and temporal brain regions as well as increased volume in the anterior white matter. These observations are important because such increases are predictive of better performance in older adults.

Taken together, these data suggest that physical activity can have beneficial effects throughout the lifespan, even for individuals with neurodegenerative disease. Animal studies in this field have documented increased angiogenesis (number of blood vessels) and enhanced formation of synapses (the connections between nerve cells) and neurogenesis (formation of new nerve cells). Decreases in each of these measures have been documented in Alzheimer brains. Hence, researchers appear to be telling us that breaking a sweat on a regular basis is a tonic for our brain.