Acute Effects of HIIT and MICT on Catestatin Dynamics in Young Males

Physical exercise acts as a major physiological stressor that alters cardiovascular and autonomic homeostasis. Catestatin (CTS), a bioactive peptide derived from chromogranin A (CgA), acts as a potent inhibitor of catecholamine secretion and modulates autonomic cardiovascular tone. However, the acute effects of distinct exercise modalities on circulating CTS dynamics and their associations with post-exercise autonomic recovery remain unclarified. The purpose of this study is to investigate the acute responses of serum catestatin and chromogranin A to high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) in healthy sedentary young males, and to evaluate their potential relationship with post-exercise heart rate recovery (HRR). Participants completed an initial incremental performance test followed by either a single HIIT session or a MICT session on a cycle ergometer. Serial blood samples and continuous cardiovascular measurements were obtained before, immediately after, and throughout a 60-minute post-exercise recovery period.

Inclusion Criteria: * Healthy male individuals aged 18-25 years * Body mass index (BMI) between 18.0 and 25.0 kg/m² * Sedentary lifestyle (no regular exercise engagement within the last 3 months; \