EXERCISE INTENSITY-DEPENDENT EFFECTS OF BDNF AND IRISIN ON CARDIOVASCULAR REGULATION

Objective. To investigate the effect of low- and high-in­tensity exercise on serum concentrations of the myoki­nes brain-derived neurotrophic factor (BDNF) and iri­sin, and to assess their correlations with cardiovascular parameters–specifically systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and heart rate (HR) – in healthy adults. Methods. Fifteen healthy individuals aged 18–29 years completed both low- and high-intensity bicycle ergome­ter exercise sessions. Blood pressure and heart rate were measured before and after each session. Serum BDNF and irisin concentrations were quantified using ELISA at three time points: baseline, 1-hour post-exercise, and 24 hours post-exercise. Statistical analysis included Wilcoxon signed-rank tests, paired t-tests, and Spear­man’s rank correlation coefficients. Results. Group-level serum concentrations of BDNF and irisin did not change significantly after either exer­cise protocol (all p > 0.05). However, serum BDNF con­centration measured 1 hour after low-intensity exercise showed a moderate negative correlation with systolic (ρ = –0.5993; p = 0.0182) and diastolic (ρ = –0.5296; p = 0.0423) arterial pressure. Serum irisin concentration was positively correlated with diastolic arterial pressure at 1 hour (ρ = 0.6427; p = 0.0098) and 24 hours (ρ = 0.5655; p = 0.0280) after low-intensity exercise. Additionally, baseline irisin concentration strongly correlated with systolic arterial pressure after high-intensity exercise (ρ = 0.7343; p = 0.0018). No correlation was found between BDNF and irisin at any time point. Conclusions. Although no significant changes in group-level myokine concentrations were observed, the fin­dings indicate that BDNF and irisin demonstrate distinct, intensity-dependent associations with cardiovascular parameters. BDNF may contribute to vasodilation fol­lowing low-intensity exercise, whereas irisin appears to be involved in vascular tone regulation and systolic responsiveness to high-intensity activity.