title: The Effect of Exercise Training on Resting Concentrations of Peripheral Brain-Derived Neurotrophic Factor (BDNF): A Meta-Analysis.
abstract: BACKGROUND
  The mechanisms through which physical activity supports healthy brain function remain to be elucidated. One hypothesis suggests that increased brain-derived neurotrophic factor (BDNF) mediates some cognitive and mood benefits. This meta-analysis sought to determine the effect of exercise training on resting concentrations of BDNF in peripheral blood.
  
  
  METHODS
  MEDLINE, Embase, PsycINFO, SPORTDiscus, Rehabilitation & Sports Medicine Source, and CINAHL databases were searched for original, peer-reviewed reports of peripheral blood BDNF concentrations before and after exercise interventions ≥ 2 weeks. Risk of bias was assessed using standardized criteria. Standardized mean differences (SMDs) were generated from random effects models. Risk of publication bias was assessed using funnel plots and Egger's test. Potential sources of heterogeneity were explored in subgroup analyses.
  
  
  RESULTS
  In 29 studies that met inclusion criteria, resting concentrations of peripheral blood BDNF were higher after intervention (SMD = 0.39, 95% CI: 0.17-0.60, p < 0.001). Subgroup analyses suggested a significant effect in aerobic (SMD = 0.66, 95% CI: 0.33-0.99, p < 0.001) but not resistance training (SMD = 0.07, 95% CI: -0.15-0.30, p = 0.52) interventions. No significant difference in effect was observed between males and females, nor in serum vs plasma.
  
  
  CONCLUSIONS
  Aerobic but not resistance training interventions increased resting BDNF concentrations in peripheral blood.
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Adam
authors.initials: A
authors.lastname: Dinoff
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Nathan
authors.initials: N
authors.lastname: Herrmann
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Walter
authors.initials: W
authors.lastname: Swardfager
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Celina S
authors.initials: CS
authors.lastname: Liu
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Chelsea
authors.initials: C
authors.lastname: Sherman
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Chan
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.|Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Krista L
authors.initials: KL
authors.lastname: Lanctôt