Autonomic and Peripheral Neurochemical Responses to Maximal Rowing Exercise

Integrated Autonomic, Neuroendocrine and Peripheral Neurochemical Responses to Maximal Rowing Exercise and Early Recovery in Elite Athletes

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.

Study Overview

• Status: Completed
• Conditions: Healhty
• Intervention / Treatment: Other: Maximal 6,000-m rowing ergometer test

Detailed Description

This observational study was conducted to investigate physiological responses to maximal rowing exercise and subsequent recovery in highly trained male athletes. The study employed a repeated-measures design, allowing assessment of exercise-induced changes across multiple physiological systems during distinct phases of recovery.

Participants completed a maximal 6,000-m rowing ergometer test under standardized laboratory conditions. Biological and physiological measurements were collected before exercise and during recovery according to a predefined protocol. Venous blood samples were obtained at baseline, immediately after exercise, and after 1 hour of recovery. Noninvasive autonomic and cardiovascular assessments were performed using the Task Force Monitor System before exercise and after 3 hours of recovery. The protocol was designed to capture both immediate biochemical responses and delayed autonomic recovery following maximal exercise.

The study focused on endocrine, peripheral neurochemical, and autonomic cardiovascular regulation. Peripheral neurochemical markers were assessed from blood samples and interpreted as components of the peripheral physiological response to exercise rather than direct indicators of central nervous system activity.

Data collection was performed under controlled laboratory conditions using standardized procedures. All measurements were obtained by trained investigators using calibrated equipment. Data quality was verified through routine review of laboratory and physiological recordings. Implausible values and technical artifacts were identified and evaluated before statistical analysis.

The planned sample size was based on the availability of elite athletes meeting the inclusion criteria and the repeated-measures design of the study. Statistical analyses were conducted using repeated-measures approaches appropriate for longitudinal within-subject data. Data distribution was assessed prior to analysis. Parametric or non-parametric tests were applied as appropriate. Effect sizes were calculated to complement significance testing. Associations between selected physiological variables were explored using correlation analyses. Missing data were handled using complete-case analysis, with no imputation procedures applied.

• Study Type: Observational
• Enrollment (Actual): 15

Contacts and Locations

Study Locations

• Poland
  • Poznań
    • Poznan, Poznań, Poland, 61-871
      • Poznań University of Physical Education

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Participants were recruited from the Polish National Rowing Team training at the Olympic Preparation Centre (COS OPO) in Wałcz, Poland.

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Male elite rowers	Other: Maximal 6,000-m rowing ergometer test; Participants completed a single maximal 6,000-m rowing ergometer test. The intervention was distinguished by a standardized all-out rowing protocol combined with peripheral blood sampling before exercise, immediately after exercise, and after 1 hour of recovery, as well as noninvasive autonomic and cardiovascular assessment at baseline and 3 hours after exercise.
Female elite rowers	Other: Maximal 6,000-m rowing ergometer test; Participants completed a single maximal 6,000-m rowing ergometer test. The intervention was distinguished by a standardized all-out rowing protocol combined with peripheral blood sampling before exercise, immediately after exercise, and after 1 hour of recovery, as well as noninvasive autonomic and cardiovascular assessment at baseline and 3 hours after exercise.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in serum cortisol concentration	Marker of hypothalamic-pituitary-adrenal axis activation and exercise-induced endocrine response.	At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum testosterone concentration	Marker of anabolic status and exercise-induced endocrine response.	At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in testosterone-to-cortisol ratio (T/C)	Marker of anabolic-catabolic balance during exercise and recovery.	At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum dopamine concentration	Peripheral neurochemical marker associated with physiological responses to exercise and recovery.	At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum serotonin concentration	Peripheral neurochemical marker associated with exercise-induced physiological responses and recovery processes.	At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum gamma-aminobutyric acid (GABA) concentration	Peripheral neurochemical marker involved in physiological regulatory processes during exercise and recovery.	At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in systolic blood pressure (sBP)	Continuous beat-to-beat systolic blood pressure measured using the Task Force Monitor System.	At rest (before the exercise test) and after 3 hours of recovery.
Change from baseline in diastolic blood pressure (dBP)	Continuous beat-to-beat diastolic blood pressure measured using the Task Force Monitor System.	At rest (before the exercise test) and after 3 hours of recovery.
Change from baseline in mean blood pressure (mBP)	Continuous beat-to-beat mean arterial pressure measured using the Task Force Monitor System.	At rest (before the exercise test) and after 3 hours of recovery
Change from baseline in heart rate (HR)	Heart rate derived from continuous electrocardiographic recordings.	At rest (before the exercise test) and after 3 hours of recovery
Change from baseline in total power spectral density of RR intervals (PSD-RRI)	Total spectral power of heart rate variability obtained from power spectral analysis of RR intervals.	At rest (before the exercise test) and after 3 hours of recovery.
Change from baseline in low-frequency power of RR intervals (LF-RRI)	Low-frequency component of heart rate variability (0.04-0.15 Hz), reflecting combined sympathetic and parasympathetic modulation.	At rest (before the exercise test) and after 3 hours of recovery.
Change from baseline in high-frequency power of RR intervals (HF-RRI)	High-frequency component of heart rate variability (0.17-0.40 Hz), considered an indicator of parasympathetic modulation.	At rest (before the exercise test) and after 3 hours of recovery.
Change from baseline in LF/HF ratio	Ratio of low-frequency to high-frequency spectral power used as an index of sympathovagal balance.	At rest (before the exercise test) and after 3 hours of recovery.
Change from baseline in baroreflex sensitivity (BRS)	Index of baroreflex function calculated using the spontaneous sequence method.	At rest (before thercisee ex test) and after 3 hours of recovery.
Change from baseline in baroreflex effectiveness index (BEI)	Index quantifying the effectiveness of baroreflex-mediated cardiovascular regulation.	At rest (before the exercise test) and after 3 hours of recovery.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in blood lactate concentration	Marker of metabolic response to maximal rowing exercise and early recovery.	At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.

Collaborators and Investigators

• Sponsor: Poznan University of Physical Education
• Collaborators: Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz
• Investigators: Study Chair: Anna Skarpańska-Stejnborn, Professor, Poznan University of Physical Education, Gorzów Wielkopolski; Faculty of Sport Sciences in Gorzów Wielkopolski

Study record dates

Study Major Dates

• Study Start (Actual): June 6, 2024
• Primary Completion (Actual): November 25, 2024
• Study Completion (Actual): March 3, 2025

Study Registration Dates

• First Submitted: June 16, 2026
• First Submitted That Met QC Criteria: June 16, 2026
• First Posted (Actual): June 22, 2026

Study Record Updates

• Last Update Posted (Actual): June 22, 2026
• Last Update Submitted That Met QC Criteria: June 16, 2026
• Last Verified: June 1, 2024

More Information

Terms related to this study

• Keywords: cortisol; dopamine; heart rate variability; testosterone; elite athletes; GABA; exercise recovery; maximal exercise; autonomic recovery; Task Force Monitor; serotonine; neuroendocrine response
• Other Study ID Numbers: B-machine

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Individual participant data sharing has not yet been determined. Future sharing of de-identified data will depend on institutional policies, ethical considerations, participant consent, and planned secondary analyses.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No