Time course of brain-derived neurotrophic factor release following acute exercise: a comparative study in young and middle-aged adults.

Purpose: Brain Derived Neurotrophic Factor (BDNF) is a crucial neurotrophin involved in memory, learning and neural plasticity. Its levels can be significantly influenced by several exogenous stimuli such as physical exercise (PE)1. For this reason, the effect of PE on BDNF release has been previously studied in physiological and pathological conditions2,3. This study aimed to evaluate the BDNF time course in two age groups of healthy males after an incremental exercise, as this comparison has not yet been made. Methods: Twenty young adults (YA: 24.7±3.6 yrs; percentage of fat mass (%FM): 11.1±5.4%; peak oxygen uptake (V̇O2peak): 49.7±9.9 ml/kg/min) and 12 middle-aged adults (MA: 54.6±5.7 yrs; %FM: 16.7±6.5%; V̇O2peak: 44.8±5.1 ml/kg/min) were enrolled. Participants underwent a cycling ramp V̇O2max test till exhaustion, while constantly measuring gas exchange using a metabolimeter. Peripheral blood samples were collected at baseline (T0), 15 min (T1), and 24 h (T2) after the exercise test. Serum BDNF (sBDNF) levels were measured using an ELISA kit. Wilcoxon signed rank and Mann Whitney U test were used to analyse the data. Results were considered significant when p<0.05. Results: sBDNF levels did not show significant changes from T0 to T1 for both YA and MA groups. Instead, a significant sBDNF increase was observed between T0 (YA T0: 13.3±1.69 ng/ml and MA T0: 12.7±0.9 ng/ml) and T2 for both groups (YA T2: 15.5±3.5 ng/ml, p<0.001; MA T2: 14.4±3 ng/ml; p<0.05). No statistical differences in sBDNF levels were found between groups in all time points, neither for absolute values nor for percentage changes. Conclusions: Our study represents a pioneering investigation that explored the impact of age on sBDNF release following acute strenuous exercise within a substantial cohort of healthy males. We detected a significant increase of sBDNF at 24 h post exercise both in YA and MA with no differences between the two groups. These findings confirm the importance of acute exercise to stimulate BDNF release also in MA people and emphasize the pivotal role of PE in promoting neurogenesis and plasticity across the entire lifespan.