Stepwise Relationship of Exercise Frequency with Serum BDNF Level among Adolescents

Abstract

Introduction: Regular participation in exercise in adolescents is associated with numerous health benefits, including improved CV, metabolic, muscular, respiratory, immune, cognitive, and neurohormonal functions. Brain-derived neutrophic factor (BDNF) is essential for several body functions, particularly the neural and cognitive functions. However, the dose-effect of exercise participation on BDNF is not fully understood among adolescents. The current study examined the relationship of serum BDNF level with moderate/vigorous exercise frequency in 703 adolescents aged 13-17 years old. Methodology: ELISA was used to evaluate serum BDNF. Additionally, the SALSA questionnaire was used to obtain the weekly frequency of moderate/vigorous exercise. Results: The ANOVA revealed differences (p=0.001) in BDNF level according to running frequency. Subsequent posthoc analysis showed that BDNF was greater (p<0.05) in adolescents participating three, four, five, six, and seven versus no and one day of exercise. Furthermore, no differences (p>0.05) were found in BDNF between exercising three, four, five, six, and seven days/week. Conclusion: The current data revealed stepwise differences in BDNF between running frequencies, peaking at five days/week. These differences in BDNF seems to plateau when participating more than three days/week. The results confirm the importance of exercise for brain health and are consistent with the current recommendations for moderate/vigorous exercise frequency.