Exercise as Modulator of Brain-Derived Neurotrophic Factor (BDNF) in Children: A Systematic Review of Randomized Controlled Trials

Background: Brain-derived neurotrophic factor (BDNF) plays a pivotal role in neuroplasticity and cognitive development. While exercise has been shown to modulate BDNF levels in adults, evidence in children remains limited and heterogeneous. Methods: A systematic review was conducted following PRISMA guidelines to examine randomized controlled trials investigating exercise effects on BDNF in children aged 5–12 years. The databases searched included FECYT, PubMed, SPORTDiscus, ProQuest Central, SCOPUS, and Cochrane Library through June 2025. Study quality was assessed using the PEDro scale. Results: Five randomized controlled trials (N = 385 participants) met inclusion criteria. Two studies (40%) demonstrated significant BDNF increases following exercise interventions. Successful interventions were characterized by neuromotor activities or martial arts programs, training frequencies ≥ 3 sessions/week, durations ≥ 12 weeks, and healthy participant populations. Methodological quality was mostly fair, with four studies rated as fair and one as good. Conclusions: Structured physical exercise may enhance BDNF levels in healthy children, with neuromotor activities and martial arts showing particular promise. However, children with overweight/obesity may require modified intervention approaches. The evidence supports the implementation of cognitively engaging physical activities in educational settings to optimize brain health during critical developmental periods, though larger standardized trials are needed to strengthen these preliminary findings.