The effect of physical exercise on circulating neurotrophic factors in healthy aged subjects: A meta-analysis and meta-regression

Vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor-1 (IGF-1) may help the brain resist both functional and structural neurodegeneration, which is critical for maintaining cognitive and neurological health in older adults. This meta-analysis and meta-regression seek to elucidate the impact of physical activity on these biomarker levels in healthy seniors, as well as to examine the influence of several moderator factors, including age, sex, period length, and time, for the first time. The standardized mean effect metric was used to assess the influence of weights, which reflected each group's relative importance in comparison to baseline data. The study looked at potential moderating factors including age, gender, and physical activity levels. The analysis of 11 studies indicated no significant effect of physical activity on VEGF levels [0.328, CI 95 % (-0.871 to 1.52); I-2 = 0.00; p = 0.592; Q = 4.14]. Physical activity had a substantial impact on brain-derived neurotrophic factor (0.827, 95 % confidence interval: 0.487 to 1.16; I-2 = 0.00; p = 0.00; Q = 78.46), with females showing particularly notable effects (Tau(2) = 0.327, Tau = 0.571, I-2 = 80.90 %, Q = 68.05, df = 15, p = 0.00). Physical activity also had a substantial effect on insulin-like growth factor 1 (0.276, 95 % confidence interval: 0.065 to 0.487; I-2 = 0.00; p = 0.10; Q = 8.35), indicating that it positively influences IGF-1 levels. Overall, while physical exercise has a significant effect on BDNF and IGF-1, more research is needed to fully understand its impact on vascular endothelial growth factor and to investigate how individual characteristics may influence exercise outcomes.