title: The effect of acute and chronic exercise on cognitive function and academic performance in adolescents: A systematic review.
abstract: OBJECTIVE
  To investigate whether exercise, proposed to enhance neuroplasticity and potentially cognitive function (CF) and academic performance (AP), may be beneficial during adolescence when important developmental changes occur.
  
  
  METHODS
  Systematic review evaluating the impact of acute or chronic exercise on CF and AP in adolescents (13-18 years).
  
  
  METHODS
  Nine databases (AMED, AusportMed, CINAHL, COCHRANE, Embase, Medline, Scopus, SPORTdiscus, Web of Science) were searched from earliest records to 31st October 2016, using keywords related to exercise, CF, AP and adolescents. Eligible studies included controlled trials examining the effect of any exercise intervention on CF, AP or both. Effect size (ES) (Hedges g) were calculated where possible.
  
  
  RESULTS
  Ten papers (11 studies) were reviewed. Cognitive domains included: executive function (n=4), memory (n=4), attention/concentration (n=2), visuo-motor speed (n=1), logical sequencing (n=1) and psychometric aptitude (n=1). All papers, nine of 10 being acute studies, reported at least one parameter showing a significant effect of exercise in improving CF and AP. However, the CF parameters displayed substantial heterogeneity, with only 37% favouring acute and chronic exercise. Where ES could be calculated, 52% of the acute CF parameters favoured rest. Memory was the domain most consistently improved by exercise. Academic performance demonstrated a significant improvement with exercise in one of two acute studies and the only chronic study (p≤0.001).
  
  
  CONCLUSIONS
  The evidence for the effect of exercise on CF and AP in adolescents is equivocal and limited in quantity and quality. Well-designed research is therefore warranted to determine the benefits of exercise in enhancing CF and AP and reducing sedentary behaviour.
authors.affiliation: Discipline of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, Australia. Electronic address: weien.li@sydney.edu.au.
authors.forename: Joanna W
authors.initials: JW
authors.lastname: Li
authors.affiliation: Discipline of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, Australia; Charles Perkins Centre, The University of Sydney, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: O'Connor
authors.affiliation: Discipline of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, Australia; School of Human Movement Studies, Charles Sturt University, Australia.
authors.forename: Nicholas
authors.initials: N
authors.lastname: O'Dwyer
authors.affiliation: Discipline of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, Australia.
authors.forename: Rhonda
authors.initials: R
authors.lastname: Orr
mesh_terms: D000073978:Academic Performance; D000293:Adolescent; D001288:Attention; D003071:Cognition; D056344:Executive Function; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D011594:Psychometrics
keywords: Executive function; Learning; Physical activity; Physical fitness; School achievements; Thinking