Decreased Serum Brain-Derived Neurotrophic Factor Concentrations 72 Hours Following Marathon Running.

Physical exercise has been linked to beneficial effects on brain plasticity. One potential key mechanism for this relationship is an exercise-induced increase of brain-derived neurotrophic factor (BDNF). However, the kinetics of BDNF in athletes during training phase, extreme exercise competition, and recovery period have not been investigated so far. We assessed serum BDNF concentrations in 51 marathon runners (23% female, mean age 43 years) in a longitudinal study design over a period of 6 months. Assessments were conducted during the training period before the marathon and after the marathon race during short-term (24 to 72 h) and long-term (3 months) follow-ups. Potential confounders (fitness level, sex, and platelet count) were included in subsequent linear-model analyses. Linear mixed-model analyses revealed a main effect of time for BDNF concentrations over the study period ( = 4.296, = 0.003). Values decreased significantly with the lowest values at 72 h after the marathon compared to baseline ( = 0.025), a finding that was more pronounced in the larger male cohort. Prolonged exercise induces a significant decrease in serum BDNF concentration 72 h post-exercise. We assume that this observation is mainly driven by regenerative mechanisms and a higher muscular utilization.