title: The impact of exercise on the cognitive functioning of healthy older adults: a systematic review and meta-analysis.
abstract: Data from epidemiological, cross-sectional, and neuroimaging research show a relationship between higher levels of exercise and reduced risk of cognitive decline but evidence from randomised controlled trials (RCTs) is less consistent. This review examines the impact of aerobic exercise, resistance training, and Tai Chi on the cognitive function of older adults without known cognitive impairment. We investigate explanations for inconsistent results across trials and discrepancies between evidence from RCTs and other research data. Twenty-five RCTs were included in the review. Meta-analysis results revealed significant improvements for resistance training compared to stretching/toning on measures of reasoning (p<0.005); and for Tai Chi compared to 'no exercise' controls on measures of attention (p<0.001) and processing speed (p<0.00001). There were no significant differences between exercise and controls on any of the remaining 26 comparisons. Results should be interpreted with caution however as differences in participant profiles, study design, exercise programmes, adherence rates, and outcome measures contribute to both discrepancies within the exercise research literature and inconsistent results across trials.
authors.affiliation: The NEIL Programme, Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland. Electronic address: kellym50@tcd.ie.
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Kelly
authors.affiliation: The NEIL Programme, Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland. Electronic address: loughred@tcd.ie.
authors.forename: David
authors.initials: D
authors.lastname: Loughrey
authors.affiliation: The NEIL Programme, Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland. Electronic address: lawlorb@stjames.ie.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Lawlor
authors.affiliation: The NEIL Programme, Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland. Electronic address: iroberts@tcd.ie.
authors.forename: Ian H
authors.initials: IH
authors.lastname: Robertson
authors.affiliation: Department of Statistics, Trinity College Dublin, Dublin 2, Ireland. Electronic address: walshc@tcd.ie.
authors.forename: Cathal
authors.initials: C
authors.lastname: Walsh
authors.affiliation: The NEIL Programme, Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland. Electronic address: brennas1@tcd.ie.
authors.forename: Sabina
authors.initials: S
authors.lastname: Brennan
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D016009:Chi-Square Distribution; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis / Q000517:prevention & control* / Q000523:psychology; D005081:Exercise Therapy / Q000379:methods* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D010809:Physical Fitness / Q000523:psychology; D055070:Resistance Training; D012307:Risk Factors; D026302:Tai Ji / Q000523:psychology; D013997:Time Factors; D016896:Treatment Outcome
keywords: Cognitive functioning; Exercise; Healthy older adults; Meta-analysis; Physical activity; Systematic review