Objectives: To assess the effects of aerobic exercise training on neurocognitive performance. Although the effects of exercise on neurocognition have been the subject of several previous reviews and meta-analyses, they have been hampered by methodological shortcomings and are now outdated as a result of the recent publication of several large-scale, randomized, controlled trials (RCTs).
Methods: We conducted a systematic literature review of RCTs examining the association between aerobic exercise training on neurocognitive performance between January 1966 and July 2009. Suitable studies were selected for inclusion according to the following criteria: randomized treatment allocation; mean age ≥18 years of age; duration of treatment >1 month; incorporated aerobic exercise components; supervised exercise training; the presence of a nonaerobic-exercise control group; and sufficient information to derive effect size data.
Results: Twenty-nine studies met inclusion criteria and were included in our analyses, representing data from 2049 participants and 234 effect sizes. Individuals randomly assigned to receive aerobic exercise training demonstrated modest improvements in attention and processing speed (g = 0.158; 95% confidence interval [CI]; 0.055–0.260; p = .003), executive function (g = 0.123; 95% CI, 0.021–0.225; p = .018), and memory (g = 0.128; 95% CI, 0.015–0.241; p = .026).
Conclusions: Aerobic exercise training is associated with modest improvements in attention and processing speed, executive function, and memory, although the effects of exercise on working memory are less consistent. Rigorous RCTs are needed with larger samples, appropriate controls, and longer follow-up periods.
ITT = intention-to-treat; RCT = randomized controlled trial.
From the Department of Psychiatry and Behavioral Sciences (P.J.S., J.A.B., B.M.H., K.W.-B., J.N.B., A.S.), Duke University Medical Center, Durham, North Carolina; and the Department of Psychology and Neuroscience (H.C., T.A.S.), Duke University, Durham, North Corolina.
The research was supported, in part, by Grants MH 49679 and HL080664-01A1 from the National Institutes of Health and Grant M01-RR-30 from the General Clinical Research Center Program, National Center for Research Resources, National Institutes of Health (J.A.B.).
Address correspondence and reprint requests to Patrick Smith, Box 3119, Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710. E-mail: Smith562@mc.duke.edu
Received for publication March 23, 2009; revision received December 3, 2009.