Effect of Exercise on Brain-Derived Neurotrophic Factor in Stroke Survivors: A Systematic Review and Meta-Analysis

Abstract

BACKGROUND: BDNF (brain-derived neurotrophic factor) is a biomarker of neuroplasticity linked with better functional outcomes after stroke. Early evidence suggests that increased concentrations after exercise may be possible for people with stroke, however it is unclear how exercise parameters influence BDNF concentration. METHODS: This systematic review and meta-analysis searched 7 electronic databases. Experimental or observational studies measuring changes in BDNF concentration after exercise in people poststroke were included. Data were extracted including characteristics of the study, participants, interventions, and outcomes. Several fixed and random effects meta-analyses were completed. RESULTS: Seventeen studies including a total of 687 participants met the eligibility criteria (6 randomized trials). Significant improvements were observed in BDNF concentration following a single session (mean difference, 2.49 ng/mL; [95% CI, 1.10–3.88]) and program of high intensity aerobic exercise (mean difference, 3.42 ng/mL; [95% CI, 1.92–4.92]). CONCLUSIONS: High intensity aerobic exercise can increase circulating BDNF concentrations, which may contribute to increased neuroplasticity. REGISTRATION: URL: https://www.crd.york.ac.uk/PROSPERO/ ; Unique identifier: CRD42021251083.

Enhancing Neuroplasticity in the Chronic Phase After Stroke: Effects of a Soft Robotic Exosuit on Training Intensity and Brain-Derived Neurotrophic Factor

“…The average increase in serum BDNF observed in this study was similar to the average post-acute exercise change reported in the post-stroke literature (2.49, 95% CI 1.10, 3.88) [20] . Our findings are thus consistent with the idea that peripheral BDNF levels increase in response to an acute bout of high intensity exercise in people after stroke [19] , [20] , with this study showing that this effect can be enhanced by interventions that enable training at a higher intensity and duration—such as the soft robotic exosuit. Reasons for the observed inter-individual variability include training dosing, factors influencing energy balance (e.g., nutrition, stress), genetic polymorphisms (e.g., Val66Met), and tissue crosstalk (discussed further in Supplementary Materials ).…”

“…BDNF is a recognized biomarker of neuroplasticity, neurogenesis, and neuroprotection [14] , [15] , and is crucial in the adaptive responses of the brain and body to changes in energy balance, such as the metabolic shifts caused by high intensity exercise [16] . Indeed, the release of BDNF is dependent on exercise intensity [17] , [18] , [19] , with exercise-induced increases in BDNF correlated with improvements in cognitive [13] and motor function [6] in both neurologically-intact humans and animal models of stroke [12] , [20] .…”

Influence of High-Intensity Interval Training on Neuroplasticity Markers in Post-Stroke Patients: Systematic Review

“…Some authors compared aerobic exercise with HIIT in patients with stroke and found larger increments in BDNF levels and longer maintenance of those BDNF and irisin levels [17]. Exploring this line of research, a meta-analysis regarding BDNF in different exercise modalities found similar results to ours regarding HIIT [48], reassuring the effect of this type of intervention. Expanding on this topic, the study from improved walking performance on the 6-MWT with higher preferred walking speed within the HIIT group [27].…”

Peripheral vascular dysfunction and the aging brain

“…These precise mechanisms are under investigation, but evidence shows that exercise increases circulating levels of the myokine Irisin, which is associated with improved cognitive function [ 112 , 113 ]. In addition, physical activity increases circulating levels of brain-derived neurotropic factor (BDNF), which heightens neuroplasticity [ 114 ]. Therefore, it has been argued that physical activity/exercise may be the most effective way to improve both vascular health and cognitive function [ 103 ].…”