The Exercise–Brain Connection
Did you know that your brain is incredibly dynamic? It can change its structure and function by adding new neurons, making new connections between neurons and even creating brand-new blood vessels, all in response to exercise.
Jeffrey A. Kleim, PhD, associate professor in the Arizona State University School of Biological and Health Systems Engineering, shares the following insights on how exercise impacts the brain.
A sedentary lifestyle affects the brain—and in turn lessens mental capacity. Sibley and Etnier (2003) found a clear connection between how much schoolchildren exercised and their cognitive performance: the more aerobic exercise the children engaged in, the better they performed on verbal, perceptual and mathematical tests. The same pattern of results was found in older adults: aerobic training improved cognitive performance (Colcombe & Kramer 2003), and active lifestyles decreased age-related risks for cognitive impairment and dementia (Yaffe et al. 2009). Not surprisingly, these cognitive effects were accompanied by clear changes in brain structure and function.
Research shows that exercise changes brain function in a lasting manner. For example, the reduced cognitive capacity in sedentary individuals is associated with different patterns of brain activity—both at rest and while performing mentally challenging tasks—than those observed in active subjects.
Plus, compared with sedentary people, active individuals show greater baseline levels of cortical activity (Dustman et al. 1990). (The cerebral cortex helps with complex cognitive tasks.)
The structure of the brain can be broken down into two general components. Gray matter contains the neurons and supporting cells, while white matter consists of the axons of these neurons (nerve cell fibers) that carry signals from one area to another.
Magnetic resonance imaging (MRI) allows for the measurement of gray and white matter. MRI scans have shown that exercise boosts overall brain volume (Colcombe et al. 2006), increasing both gray matter (Colcombe et al. 2006) and white matter (Gordon et al. 2008). These changes can occur over relatively short periods of time. After learning to juggle for only a few weeks, for example, study subjects showed increases in gray matter within regions of the brain concerned with integrating visual and motor information (Draganski et al. 2004).