Association Between Objectively Measured Physical Activity and Plasma BDNF in Adolescents: DADOS Study.

Brain-derived neurotrophic factor (BDNF) is suggested to play a key role in moderating the benefits of physical activity (PA) on cognition. Previous research found that PA may have an impact on peripheral BDNF expression. The aim of our study was to analyze the association between objectively measured PA with circulating BDNF in a group of active adolescents. Two hundred thirty-four adolescents (132 boys) aged 13.9 ± 0.3 years old from the DADOS study were included in this cross-sectional analysis. PA was assessed by GENEActiv triaxial accelerometer. Participants wore the accelerometer on their non-dominant wrist for 6 consecutive 24-h days, including weekends. PA was expressed as the average (min/day) of light, moderate, and vigorous PA. Fasting plasma BDNF concentrations at rest were measured using an enzyme-linked immunosorbent assay. Partial correlations and linear regression analyses were performed with a significance level established at p < 0.05. No correlations were found between BDNF and PA variables. Plasma levels of BDNF at rest were not significantly associated with daily PA in either boys or girls (p > 0.05). Based on previous research and our own data, the association between daily PA and baseline levels of BDNF remains inconclusive. Further research is needed to shed light on the relationship between regular PA and BDNF in adolescents.