Neurotransmitter Analysis, Stress, and Energy Availability in Athletes

Effects of Intense Physical Exertion on Neurotransmitter Levels, Stress, and Recovery in Relation to Energy Availability in Athletes

The goal of this observational study is to examine if there is a correlation between energy deficiency, neurotransmitter levels, and exercise test performance among athletes in the Polish national rowing team. The main questions it aims to answer are:

Does relative energy deficiency (RED) impact neurotransmitter levels and, consequently, athletic performance? Can monitoring energy availability, neurotransmitter levels, and psychological factors provide insights into physiological and psychological adaptations to intense training? Researchers will compare results obtained before the exercise test with those taken immediately after and following a 1-hour recovery period to assess changes in performance, biochemical markers, and psychological responses.

Participants will:

• Engage in a standardized exercise test.
• Undergo assessments of energy availability, neurotransmitter levels, and performance at multiple time points (pre-exercise, immediately post-exercise, and post-1-hour recovery).
• Complete psychological questionnaires assessing stress levels, recovery, and energy availability.

This study aims to identify potential links between energy status, biochemical responses, psychological well-being, and athletic performance, allowing for targeted interventions to optimize training outcomes.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Diagnostic test: 6K Max Effort Erg Test

Detailed Description

The primary goal of this project is to optimize athletic training for the national rowing team through comprehensive multi-dimensional monitoring. This approach aims to enhance athletes' performance capabilities and readiness for high-level competition. The Polish national rowing team consistently wins medals at international events, with the Olympic medal being the ultimate achievement for these athletes. Given this high standard, special attention is placed on preparing the athletes, not only in terms of physical readiness but also through continuous monitoring of adaptive processes. This proactive approach enables early detection of adverse changes, allowing for rapid adjustments to the training process to prevent fatigue and overtraining.

Building on the previous year's findings, this project focuses on the effects of relative energy deficiency (RED) in sports. Introduced by the International Olympic Committee in 2014, RED refers to a syndrome of impairments that arise from low energy availability (EA) due to an imbalance between energy intake and expenditure relative to lean body mass. In high-performance sports like rowing, athletes experience internal and external pressures to maintain peak performance, which often impacts energy intake and expenditure. Low energy availability (LEA) initially leads to negative energy balance and weight loss, as the body's energy reserves are used to meet demand. Over time, chronic LEA results in metabolic and physiological adaptations, reducing total energy expenditure to prevent further weight loss. While body weight and fat mass may stabilize, athletes can experience compromised physiological functions due to LEA.

LEA impacts recovery, muscle mass, neuromuscular function, and increases injury risk, all of which can detrimentally affect performance. Sustained LEA aimed at reducing body mass or fat levels can lead to health and performance declines, a pattern seen in both male and female athletes. Recent awareness highlights that male rowers, previously assumed to be protected due to their higher lean mass and body size, may also experience RED-S. The demands of high-level rowing, often involving six hours of intense daily training with long endurance sessions and strength workouts, create challenges in meeting energy requirements.

This project involves biochemical assessments alongside psychological questionnaires to monitor athletes' stress, recovery, and energy availability. Such comprehensive monitoring provides insights into both the physical and mental responses to training stressors, supporting the development of tailored interventions for optimal performance and health in elite rowers.

• Study Type: Observational
• Enrollment (Actual): 27

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

The study will be conducted at the Olympic Preparation Center COS OPO in Wałcz. Testing will begin in the morning with fasting body composition measurements and blood sampling to determine baseline values of measured parameters. Psychological assessments, including questionnaires tailored for the study, will also be administered. Following this, participants will undergo an exercise test in a specialized training room equipped with modern rowing ergometers, during which each athlete will row a distance of 6,000 meters as quickly as possible. Athletes will be encouraged to maximize their effort throughout the test. Additional blood samples will be collected according to the testing schedule. The blood samples will then be transported to the ZWKF AWF laboratory in Poznań for parameter analysis.

Description

Inclusion Criteria:

• Gender and Biological Sex Alignment: Participants' self-identified gender must align with their biological sex due to the effects of sexual dimorphism on athletic performance.

Sex: Both male and female athletes are eligible to participate. Training Level: Participants must be highly trained, with a minimum of 5 years of consistent, high-level athletic training experience.

Experience: Participants should have competitive experience at a regional, national, or international level.

Health Status: Participants must be healthy, with no current or chronic medical conditions, injuries, or diseases that could affect study outcomes.

Exclusion Criteria:

• Gender-Biological Sex Mismatch: Individuals whose self-identified gender does not align with their biological sex are excluded, to maintain consistency in data affected by sexual dimorphism.

Training Level: Recreational athletes, individuals with less than 3 years of high-level training, or those lacking competitive experience are excluded.

Health Conditions: Individuals with any medical conditions, chronic illnesses, acute injuries, or undergoing treatments that may interfere with athletic performance or study variables are excluded.

Medication: Use of medications or supplements that could influence metabolism, muscle composition, or overall physical performance results in exclusion.

Other Factors: Any other factors, such as lifestyle habits (e.g., smoking, excessive alcohol use), that could affect physiological responses to training and testing, are grounds for exclusion.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Group 1; Eight female athletes	Diagnostic test: 6K Max Effort Erg Test; "6K Max Effort Erg Test", involves participants completing a 6000-meter rowing distance on an ergometer as quickly as possible. This test is designed to measure peak endurance and performance under controlled conditions and will serve as a primary assessment of each athlete's physical output and adaptive capacity.
Group 2; 19 male athletes	Diagnostic test: 6K Max Effort Erg Test; "6K Max Effort Erg Test", involves participants completing a 6000-meter rowing distance on an ergometer as quickly as possible. This test is designed to measure peak endurance and performance under controlled conditions and will serve as a primary assessment of each athlete's physical output and adaptive capacity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes from baseline in cortisol level.	Marker of stress level.	At rest (before the exercise test), 1 minute after the end of the test, after 1 hour of recovery.
Changes from baseline in testosterone level.	Marker of anabolic activity.	At rest (before the exercise test), 1 minute after the end of the test, after 1 hour of recovery.
Changes from baseline in serotonin level.	Marker of mood regulation and emotional well-being	At rest (before the exercise test), 1 minute after the end of the test, after 1 hour of recovery.
Changes from in serotonin level.	Marker of mood regulation and emotional well-being.	At rest (before the exercise test), 1 minute after the end of the test, after 1 hour of recovery.
Changes from baseline in gamma-aminobutyric acid (GABA) level.	Marker of neuroinhibition.	At rest (before the exercise test), 1 minute after the end of the test, after 1 hour of recovery.
Changes from baseline in dopamine level.	Marker of stress and adrenal function.	At rest (before the exercise test), 1 minute after the end of the test, after 1 hour of recovery.
Changes from baseline in tryptophan level.	Marker of mood regulation, serotonin synthesis.	At rest (before the exercise test), 1 minute after the end of the test, after 1 hour of recovery.
Baseline Mood Profile of Athletes Before Exercise Test Using POMS Questionnaire.	The Profile of Mood States (POMS) questionnaire measures mood states and emotional well-being.	At rest (before the exercise test).
Baseline Stress and Recovery Profile of Athletes Before Exercise Test Using RESTQ-76 Sport Questionnaire.	The Recovery-Stress Questionnaire for Athletes (RESTQ-76 SPORT), 76-item version questionnaire measures stress and recovery balance in athletes.	At rest (before the exercise test).
Baseline Psychological Strain Assessment of Athletes Before Exercise Test Using APSQ Questionnaire.	The Athlete Psychological Strain Questionnaire (APSQ) measures psychological strain and mental health challenges in athletes.	At rest (before the exercise test).
Baseline Eating Behavior and Attitudes of Athletes Before Exercise Test Using EDE-Q 6.0 Questionnaire.	The Eating Disorder Examination Questionnaire (EDE-Q 6.0) measures the severity of eating disorder behaviors and attitudes.	At rest (before the exercise test).
Baseline Eating Behavior and Attitudes of Athletes Before Exercise Test Using EDE-Q 6.0 Questionnaire.	The Eating Disorder Examination Questionnaire (EDE-Q) measures the severity of eating disorder behaviors and attitudes.	At rest (before the exercise test).
Baseline Energy Availability and Health Assessment of Female Athletes Before Exercise Test Using LEAF Questionnaire.	The Eating Disorder Examination Questionnaire (EDE-Q) measures the severity of eating disorder behaviors and attitudes.	At rest (before the exercise test).
Baseline Energy Availability and Health Assessment of Male Athletes Before Exercise Test Using LEAM Questionnaire.	The Eating Disorder Examination Questionnaire (EDE-Q) measures the severity of eating disorder behaviors and attitudes.	At rest (before the exercise test).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Baseline Dietary Habits Assessment of Athletes Before Exercise Test Using Nutrition Questionnaire	The nutrition questionnaire assesses dietary habits, nutrient intake, meal frequency and types, potential deficiencies or excesses, food preferences, supplement use, and overall diet quality.	At rest (before the exercise test).
Baseline Body Composition Assessment of Athletes Before Exercise Test	Baseline body composition measurements will be conducted using the bioimpedance method to assess athletes' body fat, muscle mass, and overall composition prior to the exercise test.	At rest (before the exercise test).

Collaborators and Investigators

• Sponsor: Poznan University of Physical Education

Study record dates

Study Major Dates

• Study Start (Actual): November 10, 2024
• Primary Completion (Actual): November 10, 2024
• Study Completion (Actual): November 15, 2024

Study Registration Dates

• First Submitted: November 8, 2024
• First Submitted That Met QC Criteria: November 8, 2024
• First Posted (Actual): November 12, 2024

Study Record Updates

• Last Update Posted (Actual): November 20, 2025
• Last Update Submitted That Met QC Criteria: November 17, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: fatigue; athletes; neurotransmitters; low energy availability
• Additional Relevant MeSH Terms: Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Fatigue
• Other Study ID Numbers: RowersMF2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: There is not a plan to make individual participant data (IPD) available because protecting participant confidentiality is a priority, especially given the sensitive nature of personal health and performance data collected in this study. Additionally, there may be limitations in data-sharing infrastructure and resources needed to anonymize and securely manage IPD for external access. Ensuring compliance with privacy regulations and ethical standards also restricts the feasibility of making IPD broadly available to other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No