The effect of exercise training on neurotrophins in obese and overweight individuals: A systematic review and meta-analysis of randomized controlled trials

The purpose of this research was to conduct a systematic review and meta-analysis on the effect of exercise training on neurotrophin levels in obese and overweight individuals. The research evaluated the effect of exercise training on neurotrophins in the databases of PubMed, Science Direct, Scopus, and Google Scholar with identified keywords among papers published from 2000 onwards. After preliminary screening, full-text studies as well as critical evaluation of the papers meeting the inclusion criteria were analyzed. Finally, 12 studies entered systematic research, and 6 studies entered meta-analysis research. The results show that exercise training has an addictive effect on neurotrophin levels in obese individuals, but this addictive effect is not significant. The present meta-analyze shows that the brain -Derived Neurotrophic Factor (BDNF) response to exercise in obese individuals is increasing, but the increase is not significant (Difference in means = -0.42 pg/ml, P = 0.460). On the other hand, the Nerve Growth Factor (NGF) response to exercise is also increasing which is significant (Z = 2.12, P = 0.034). Thus, it can be concluded that exercise cannot increase neurotrophins in obese and overweight individuals; although, further studies are needed in this area.