Molecular mechanisms of the physical exercise-induced increase of brain-derived neurotrophic factor levels: a systematic review

Physical inactivity triggers several metabolic syndromes and influences cognitive function, including the development of dementia. Exercise can help to prevent these negative effects. However, there is currently limited research examining how exercise affects cognitive function through brain-derived neurotrophic factor (BDNF) levels, and the underlying mechanisms remain unclear. The aim of this study was to analyze existing literature on the effect of physical exercise on brain-derived neurotrophic factor (BDNF) levels as a biomarker of cognitive function. Several journal databases, including Scopus, Web of Science, PubMed, and Science Direct, were searched for this study. The study considered several variables, including studies on BDNF, high-intensity exercise, and moderate-intensity exercise published within the last ten years. Articles that did not meet the inclusion criteria (e.g. animal studies) were excluded from this systematic review. Using databases from PubMed, Science Direct, Web of Science, and Scopus, a total of 152 publications were identified. Ten carefully selected, peer-reviewed articles addressed the need for this systemic change. Standard operating procedures for this study were established using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Based on the results of this comprehensive study, it is evident that exercise increases BDNF levels in humans. Although high-intensity exercise is more effective in increasing BDNF levels in humans than moderate-intensity exercise, further research is needed for selection of the optimal physical load required for BDNF expression. Physical exercise is recommended to improve brain development and memory ability.