Aerobic exercise
Regular exercise has been shown to counter the shrinking of the hippocampus and memory impairment that naturally occurs in late adulthood. Sedentary adults over age 55 show a 1–2% decline in hippocampal volume annually. A neuroimaging study with a sample of 120 adults revealed that participating in regular aerobic exercise increased the volume of the left hippocampus by 2.12% and the right hippocampus by 1.97% over a one-year period. Subjects in the low intensity stretching group who had higher fitness levels at baseline showed less hippocampal volume loss, providing evidence for exercise being protective against age-related cognitive decline. In general, individuals that exercise more over a given period have greater hippocampal volumes and better memory function. Aerobic exercise has also been shown to induce growth in the white matter tracts in the anterior corpus callosum, which normally shrink with age.