Aerobic exercise increases brain-derived neurotrophic factor (BDNF) in sub-acute stroke: a randomized controlled trial

Background Brain-derived neurotrophic factor (BDNF) is a key neurotrophin due to its role in neuron process outgrowth, plasticity, and neuronal survival. Aerobic exercise can induce BDNF release and may ultimately maximize post-stroke recovery.Objectives This study aimed to determine if a program of moderate-to-high-intensity aerobic exercise increased concentrations of BDNF in subacute stroke survivors compared to usual care.Methods A parallel-group, RCT was undertaken in people with subacute stroke undergoing rehabilitation. Participants were randomly allocated to usual care (control group) or usual care plus an 8-week program of moderate-high intensity treadmill walking (3 x 30 min sessions per week) (experimental group). Serum BDNF was collected by blinded assessors at baseline (Week 0), at the end of the intervention period (Week 8), and at 6 months follow up (Week 26).Results Sixty-seven participants (n = 67) were recruited to the study (avg time post-stroke: 26 days). A between-group difference in BDNF levels across the three time points (F = 3.14, p = 0.048) was found. From Week 0 to Week 8, BDNF levels in the experimental group increased by 18% (p = 0.020) and then decreased from Week 8 to Week 26 by 18% (p = 0.021), returning to baseline levels. No change was found for the control group (Week 0 to Week 8 p = 0.378, Week 8 to Week 26 p = 0.412).Conclusions As concentrations of BDNF increased immediately after a program of aerobic exercise, this may present a potential neurobiological mechanism to enhance recovery after stroke.