A meta-analytic review of the effects of exercise on brain-derived neurotrophic factor

Abstract

Consistent evidence indicates that exercise improves cognition and mood, with preliminary evidence suggesting that brain-derived neurotrophic factor (BDNF) may mediate these effects. The aim of the current meta-analysis was to provide an estimate of the strength of the association between exercise and increased BDNF levels in humans across multiple exercise paradigms. We conducted a meta-analysis of 29 studies (N = 1111 participants) examining the effect of exercise on BDNF levels in three exercise paradigms: (1) a single session of exercise, (2) a session of exercise following a program of regular exercise, and (3) resting BDNF levels following a program of regular exercise. Moderators of this effect were also examined. Results demonstrated a moderate effect size for increases in BDNF following a single session of exercise (Hedges' g = 0.46, p < 0.001). Further, regular exercise intensified the effect of a session of exercise on BDNF levels (Hedges' g = 0.59, p = 0.02). Finally, results indicated a small effect of regular exercise on resting BDNF levels (Hedges' g = 0.27, p = 0.005). When analyzing results across paradigms, sex significantly moderated the effect of exercise on BDNF levels, such that studies with more women showed less BDNF change resulting from exercise. Effect size analysis supports the role of exercise as a strategy for enhancing BDNF activity in humans, but indicates that the magnitude of these effects may be lower in females relative to males.

Keywords: BDNF; Brain-derived neurotrophic factor; Exercise; Meta-analysis; Physical activity.

Conflict of interest statement

Conflict of Interest

In the past 3 years Dr. Otto has served as a paid consultant for MicroTransponder Inc., Concert Pharmaceuticals, and ProPhase; provided expert consensus opinion for Otsuka Pharmaceuticals; received royalty support for use of the SIGH-A from ProPhase; and received book royalties from Oxford University Press, Routledge, and Springer. The other authors have no conflicts to report.

Copyright © 2014 Elsevier Ltd. All rights reserved.

Figures

Figure 1

Study selection process

Figure 2

Effect sizes of the association between exercise and BDNF levels following acute exercise. s, serum; a, acute exercise.

Figure 3

Effect sizes of the association between acute exercise and BDNF levels following programmed regular exercise. c, change after programmed exercise.

Figure 4

Effect sizes of the association between exercise and resting BDNF levels following programmed regular exercise. s, serum; r, resting BDNF levels after programmed exercise.