Autonomic and Peripheral Neurochemical Responses to Maximal Rowing Exercise

The goal of this observational study is to characterize autonomic, neuroendocrine, and peripheral neurochemical responses to maximal rowing exercise and early recovery in highly trained male athletes. The main questions it aims to answer are: * How do circulating concentrations of cortisol, testosterone, dopamine, serotonin, gamma-aminobutyric acid (GABA), and the testosterone-to-cortisol ratio change in response to maximal rowing exercise and during the first hour of recovery? * How do autonomic cardiovascular parameters, including heart rate variability, blood pressure variability, and baroreflex sensitivity, change 3 hours after maximal exercise compared with baseline values? * Do endocrine, peripheral neurochemical, and autonomic responses demonstrate similar or divergent recovery patterns following maximal exercise? Participants will: * Perform a maximal 6,000-m rowing ergometer test. * Undergo venous blood sampling before exercise, immediately after exercise, and 1 hour after exercise recovery for assessment of endocrine and peripheral neurochemical markers. * Undergo noninvasive cardiovascular and autonomic assessment using the Task Force Monitor System before exercise and 3 hours after exercise recovery.

Inclusion Criteria: Highly trained rowers competing at national or international level Regular participation in structured rowing training Current sports medical clearance for maximal exercise testing Ability to complete a maximal 6,000-m rowing ergometer test Written informed consent to participate in the study Exclusion Criteria: Acute illness, infection, or injury before testing Any diagnosed cardiovascular, metabolic, neurological, endocrine, or inflammatory disorder Use of medications or supplements that could affect cardiovascular, endocrine, metabolic, or neurochemical responses Inability to complete the maximal rowing test Inability or refusal to provide blood samples Non-compliance with study procedures or pre-test instructions