Effects of physical exercise on plasma brain-derived neurotrophic factor in neurodegenerative disorders: A systematic review and meta-analysis of randomized controlled trials

• Published in: Neuroscience and biobehavioral reviews Vol. 128; pp. 394 - 405
• Main Authors: Ruiz-González, David, Hernández-Martínez, Alba, Valenzuela, Pedro L., Morales, Javier S., Soriano-Maldonado, Alberto
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2021
• Subjects: Aerobic exercise; Mild cognitive impairment; Multiple sclerosis; Neurodegeneration; Neurotrophins; Parkinson disease; Physical activity; Resistance training; Multiple sclerosis; Physical activity; Mild cognitive impairment; Neurodegeneration; Resistance training; Parkinson disease; Neurotrophins; Aerobic exercise
• ISSN: 0149-7634; 1873-7528
• DOI: 10.1016/j.neubiorev.2021.05.025

•Exercise increases plasma BDNF levels in individuals with neurodegenerative disorders.•Effects were consistent for different exercise type, weekly volume, and intervention length.•These findings support the benefits of exercise against neurodegenerative disorders. Neurodegenerative disorders are associated with reduced levels of brain-derived neurotrophic factor (BDNF). We aimed to assess the effect of exercise interventions on plasma BDNF levels in individuals with neurodegenerative disorders. Eighteen randomized controlled trials (RCT) assessing the effects of exercise interventions versus no exercise on plasma BDNF levels in individuals with neurodegenerative disorders (i.e., multiple sclerosis, Parkinson’s disease, mild cognitive impairment [MCI] and Alzheimer’s disease) were included. Overall, exercise interventions induced a significant increase in plasma BDNF levels (SMD=2.22, 95% CI=1.33–3.12, p<0.001; 18 studies), which was separately confirmed for multiple sclerosis (SMD= 2.40, 95% CI= 1.30–3.50, p<0.001; 10 studies) and Parkinson's disease (SMD= 10.00, 95% CI= 2.48–17.51, p=0.009; 3 studies), with a non-significant trend also observed for MCI (SMD= 1.07, 95% CI= -0.14–2.28, p=0.080; 4 studies). BDNF levels significantly increased regardless of exercise type (p<0.001, p=0.003 and p=0.020 for combined, aerobic and resistance exercise, respectively), weekly exercise volume (p<0.001 for both ≥150 and <150 min/week) and intervention length (p<0.001 for both interventions of ≥12 and <12 weeks). In conclusion, physical exercise interventions increase plasma BDNF levels in individuals with neurodegenerative disorders. PROSPERO registration number: CRD42020199459.