A recent randomized clinical trial demonstrates the efficacy of aerobic exercise for cognition in adults aged 20–67. The effect of aerobic exercise on executive function was more pronounced as age increased, suggesting that it may mitigate age-related declines. Furthermore, increased cortical thickness suggests that aerobic exercise contributes to brain health in individuals as young as age 20. In a randomized, parallel-group, observer-masked, community-based clinical trial, 132 cognitively normal individuals aged 20–67 with below median aerobic capacity were randomly assigned to 1 of 2 6-month, 4-times-weekly conditions: aerobic exercise and stretching/toning. Efficacy measures included aerobic capacity, cognitive function in several domains, everyday function, body mass index (BMI), and cortical thickness. Researchers found:

• Aerobic capacity increased significantly, and BMI decreased significantly in the aerobic exercise but not in the stretching/toning condition.
• Executive function improved significantly in the aerobic exercise condition; this effect was moderated by age.
• At age 40, the executive function measure increased by 0.228 SD, and by 0.596 SD at age 60.
• Cortical thickness increased significantly in the aerobic exercise group in a left frontal region and did not interact with age.