Table 1.

Meta-analyses examining the relationship between physical activity, exercise, and cognitive function.

Author, year	Methodology/Number of studies	Inclusion/Exclusion Criteria	Findings
Etnier et al., 1997	Meta-analysis of observational and interventional studies/134	All studies providing adequate data for effect size calculation, utilizing a cognitive test measure as the outcome variable, and in which data on the exercise training paradigm was provided were included.	Overall effect size of 0.25. Cross-sectional/ correlational studies showed the strongest effect sizes, followed by chronic exercise training, and then acute exercise. The effect of exercise was smaller among more methodologically rigorous studies.
Colcombe & Kramer, 2003	Meta-analysis of published, randomized trials from 1966 to 2001 examining the impact of exercise on cognitive function/18	Studies utilizing random assignment to intervention, supervised exercise, an aerobic exercise intervention, and an average age of participants ≥ 55.	Exercise improved cognitive function for tests of executive function, controlled processing, visuospatial abilities, and speed.
Sibley & Etnier, 2003	Meta-analysis of published observational and interventional studies before January, 2002 examining the relationship between physical activity, exercise, and cognition in children/44	All studies providing adequate data for effect size calculation, utilizing a cognitive test measure as the outcome variable, and in which data on the exercise training paradigm was provided were included.	Overall effect size of 0.32. This association was similar across different study designs and study populations.
Heyn et al., 2004	Meta-analysis of published articles and unpublished manuscripts from 1970 to 2003 of randomized trials evaluating exercise in persons 65 years of age or older with cognitive impairment/30 total (9 for cognitive function)	Studies utilizing an exercise program or form of rehabilitative exercises, physical activity, fitness, or recreational therapy, nonintervention control group, subjects >65 years of age, baseline Mini-Mental Status Examination (MMSE) < 26 or diagnosis of cognitive impairment, minimum of 5 subjects in each group.	Exercise resulted in improvements in strength (ES = 0.75), physical fitness (ES = 0.69), functional performance (ES = 0.59), cognitive performance (ES = 0.57), and behavior (ES = 0.54).
Etnier et al., 2006	Meta-regression published and unpublished studies from 1927 to October 2005, both observational and interventional, examining the relationship between fitness and cognitive function (Cardiovascular Fitness Hypothesis)/8 cross-sectional; 24 post-test; 30 pre–post; 10 correlational	Studies included if they examined the relationship between current fitness level or participation in an exercise program and a measure of cognitive performance, used a chronic exercise paradigm, a cross-sectional design in which cognitive performance was examined in a “fit” and a “less fit” group, or a correlational design in which cognition and fitness were correlated, assessed aerobic fitness using a submaximal or maximal measure of VO2max, or a composite measure of fitness that included a measure of VO2max.	Cross-sectional ES = 0.40; post-test ES = 0.27; pre–post ES = 0.25; correlational ES = 0.29. Although cognitive function improved in pre –post studies (ES = 0.25), aerobic fitness was negatively associated with aerobic fitness.
Angevaren et al., 2008	Meta-analysis of all published randomized controlled trials comparing aerobic physical activity programs with any other intervention or no intervention with participants older than 55 years of age without known cognitive impairment/11	Studies including individuals without known cognitive impairment (including depression), randomly assigned to treatment, and also included a fitness parameter.	The largest effects on cognitive function were found on motor function and auditory attention (effect sizes of 1.17 and 0.50 respectively). Moderate effects were observed for cognitive speed (speed at which information is processed; effect size 0.26) and visual attention (effect size 0.26).
Hamer & Chida, 2009	Meta-analysis of published, prospective studies in which a diagnosis of a neurodegenerative disease was available/ 16 studies. 3219 participants non-demented at baseline	Studies included if they provided a measure of physical activity and a diagnosis of neurodegenerative illness.	The risk ratio of dementia in the highest physical activity category compared with the lowest was 0.72 overall: 0.55 for Alzheimer’s, 0.55 and 0.82 for Parkinson’s.
Smith, Blumenthal, Babyak et al., 2010; Smith, Blumenthal, Hoffman et al., 2010	Meta-analysis of published and unpublished randomized trials from 1966 to 2009 examining the impact of aerobic training on cognitive function/29	Studies in which random assignment was used, mean age ≥ 18 years of age and non-demented, duration of treatment ≥1 month, intervention involved aerobic exercise training (e.g. brisk walking, biking, or jogging), and the presence of a control group that did not engage in aerobic exercise.	Aerobic exercise training was associated with modest improvements in attention and processing speed (g = 0.16), executive function (g = 0.12), and memory (g = 0.13). Effects were stronger in trials among individuals with mild cognitive impairment.
McMorris et al., 2011	Meta-analysis of published studies examining the impact of acute exercise on working memory performance/24	Studies were included if they examined healthy individuals, the exercise intervention involved the activation of large muscle groups, repeated measures, within-subject design was used, data were provided showing the intensity of the exercise, the dependent variables were response time and/or accuracy/error, and tests met the criteria for classification as working memory tasks.	Exercise was associated with significantly improved response time (g = −1.41), but had a detrimental impact on accuracy (g = 0.40). It was concluded that acute, intermediate intensity exercise has a strong beneficial effect on speed of response in working memory tasks but a low to moderate, detrimental one on accuracy.
Aarsland et al., 2010	Meta-analysis of published, prospective studies examining the relationship between physical activity and vascular dementia/24 with 1378 patients with VaD and 10,108 controls	Studies were included if case selection included total dementia, VaD or vascular cognitive impairment, a prospective design was utilized, diagnosis of dementia and VaD were based on operational criteria, exercise was measured, a temporal relationship between exercise and dementia could be observed, and reported an odds ratio (OR) or relative risk (RR).	Physical activity was associated with reduced risk of developing VaD: OR 0.62.
Lambourne & Tomporowski, 2010	Meta-regression of impact of acute exercise bouts on arousal published from 1900 to December, 2008/29	Studies were included if they were performed on healthy adults, the exercise intervention elicited the activation of large muscles and cardiovascular responses, used a within-subject design, and published in English.	Cognitive task performance was impaired during exercise (mean ES = −0.14), but improved performance following exercise for tasks involving rapid decisions and automatized behaviors (mean ES = 0.20). Arousal continued to facilitate speeded mental processes and also enhanced memory storage and retrieval, and positive effects were observed following exercise regardless of study protocol.
Sofi et al., 2011	Meta-analysis of published, prospective studies examining the association between physical activity and cognitive decline among non-demented subjects/15 (including 12 cohorts)	Studies were included if they utilized a prospective cohort design, examined the association between physical activity and cognitive function as the primary or secondary outcome, were comprised of non-demented subjects evaluated at baseline, and used clear definitions of methods to assess cognitive performance and cognitive decline.	33,816 non-demented subjects were included with a follow-up of 1–12 years with 3210 individuals exhibiting cognitive decline during the follow-up. Random-effects model showed that subjects who performed a high level of physical activity were 38% less likely to develop cognitive decline during the follow-up (HR = 0.62). Low-to-moderate levels of exercise were also protective exercise also showed a significant protection (35%) against cognitive impairment (HR = 0.65).
Chang et al., 2012	Meta-analysis of published studies examining the impact of acute bouts of exercise on cognitive function/79	Studies included if they examined the effects of acute exercise on cognitive performance (defined as “performed on a single day”) and exercise was defined based upon the American College of Sports Medicine 2010 definition	Overall analyses suggested a small, positive impact of acute exercise on cognition (g = 0.097, n = 1034), and this was consistent across phases of exercise: during exercise (g = 0.101), immediately following exercise (g = 0.108), and after a delay (g = 0.103).
Morgan et al., 2012	Meta-analysis of prospective studies examining the relationship between leisure-time and work-related physical activity on dementia/21	Studies were included if they utilized a prospective cohort design, measured the association between physical activity and cognitive impairment or dementia, reported a validated, clinically-relevant outcome measure of cognitive impairment or a pre-specified decline in cognitive function from baseline	Physical activity was associated with lower likelihood of developing cognitive impairment (OR = 0.66) and dementia (OR = 0.78), and these results did not appear to be related to follow-up length.
Hindin & Zelinski, 2012	Meta-analysis of published studies examining extended practice and aerobic exercise interventions/17	Studies included healthy, cognitively unimpaired community-residing adults ≥ 55 years of age, original research reporting extended cognitive domain practice of basic tasks such as N-back or aerobic fitness interventions hypothesizing cognitive improvements, experimental and control groups; multiple-session training; and pre- and post-tests of untrained cognitive tasks.	Aerobic exercise training was associated with improvements in cognitive function (ES = 0.33).

ES = effect size; HR = hazard ratio; OR = odds ratio; VaD = vascular dementia.