title: BDNF mediates improvements in executive function following a 1-year exercise intervention.
abstract: Executive function declines with age, but engaging in aerobic exercise may attenuate decline. One mechanism by which aerobic exercise may preserve executive function is through the up-regulation of brain-derived neurotropic factor (BDNF), which also declines with age. The present study examined BDNF as a mediator of the effects of a 1-year walking intervention on executive function in 90 older adults (mean age = 66.82). Participants were randomized to a stretching and toning control group or a moderate intensity walking intervention group. BDNF serum levels and performance on a task-switching paradigm were collected at baseline and follow-up. We found that age moderated the effect of intervention group on changes in BDNF levels, with those in the highest age quartile showing the greatest increase in BDNF after 1-year of moderate intensity walking exercise (p = 0.036). The mediation analyses revealed that BDNF mediated the effect of the intervention on task-switch accuracy, but did so as a function of age, such that exercise-induced changes in BDNF mediated the effect of exercise on task-switch performance only for individuals over the age of 71. These results demonstrate that both age and BDNF serum levels are important factors to consider when investigating the mechanisms by which exercise interventions influence cognitive outcomes, particularly in elderly populations.
authors.affiliation: Department of Psychology, University of Pittsburgh Pittsburgh, PA, USA ; Center for the Neural Basis of Cognition, University of Pittsburgh Pittsburgh, PA, USA.
authors.forename: Regina L
authors.initials: RL
authors.lastname: Leckie
authors.affiliation: Department of Psychology, University of Pittsburgh Pittsburgh, PA, USA ; Center for the Neural Basis of Cognition, University of Pittsburgh Pittsburgh, PA, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Oberlin
authors.affiliation: Department of Psychology, University of Iowa Iowa City, IA, USA.
authors.forename: Michelle W
authors.initials: MW
authors.lastname: Voss
authors.affiliation: Department of Psychology, Ohio State University Columbus, OH, USA.
authors.forename: Ruchika S
authors.initials: RS
authors.lastname: Prakash
authors.affiliation: Cardiovascular Research Institute, University of Kansas Medical Center Kansas City, KS, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Szabo-Reed
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois Champaign-Urbana, IL, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Chaddock-Heyman
authors.affiliation: Department of Preventative Medicine, Northwestern University Medical School Chicago, IL, USA.
authors.forename: Siobhan M
authors.initials: SM
authors.lastname: Phillips
authors.affiliation: Department of Kinesiology, Wayne State University Detroit, MI, USA.
authors.forename: Neha P
authors.initials: NP
authors.lastname: Gothe
authors.affiliation: Department of Kinesiology, Kansas State University Manhattan, KS, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Mailey
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois Champaign-Urbana, IL, USA.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Vieira-Potter
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois Champaign-Urbana, IL, USA.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Martin
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois Champaign-Urbana, IL, USA.
authors.forename: Brandt D
authors.initials: BD
authors.lastname: Pence
authors.affiliation: Department of Neuroscience, George Mason University Fairfax, VA, USA.
authors.forename: Mingkuan
authors.initials: M
authors.lastname: Lin
authors.affiliation: Department of Psychology, George Mason University Fairfax, VA, USA.
authors.forename: Raja
authors.initials: R
authors.lastname: Parasuraman
authors.affiliation: Department of Psychology, George Mason University Fairfax, VA, USA.
authors.forename: Pamela M
authors.initials: PM
authors.lastname: Greenwood
authors.affiliation: School of Molecular Biology, George Mason University Fairfax, VA, USA.
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Fryxell
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois Champaign-Urbana, IL, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Woods
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois Champaign-Urbana, IL, USA ; Department of Kinesiology and Community Health, University of Illinois Champaign-Urbana, IL, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: McAuley
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois Champaign-Urbana, IL, USA.
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Kramer
authors.affiliation: Department of Psychology, University of Pittsburgh Pittsburgh, PA, USA ; Center for the Neural Basis of Cognition, University of Pittsburgh Pittsburgh, PA, USA ; Center for Neuroscience, University of Pittsburgh Pittsburgh, PA, USA.
authors.forename: Kirk I
authors.initials: KI
authors.lastname: Erickson
keywords: BDNF; aging; cognition; executive function; exercise; mediation analysis; physical activity