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Completed

NCT Number: NCT07681362

IL-6 and Cortisol Responses to Cycling Exercise

This study aimed to investigate salivary interleukin-6 (IL-6) and cortisol responses following short-term and long-term cycling exercise in team athletes with different cardiorespiratory fitness levels. Participants completed a Wingate anaerobic cycling test and a YMCA submaximal cycling test in a randomized crossover design separated by a seven-day washout period. Saliva samples were collected before exercise, immediately after exercise, and 30 minutes after exercise to determine IL-6 and cortisol concentrations. The study also examined whether cardiorespiratory fitness level influenced the magnitude of these physiological responses.

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Key information

Conditions

Exercise Physiology Behavior Cardiorespiratory Fitness Cortisol Interleukin-6 Motor Activity

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Ondokuz Mayis University Faculty of Sport Sciences

Samsun, 55139, Turkey (Türkiye)

About this study

Exercise-induced physiological stress activates numerous neuroendocrine and inflammatory pathways, including the hypothalamic-pituitary-adrenal axis and cytokine-mediated responses. Cortisol and interleukin-6 (IL-6) are among the most commonly investigated biomarkers of exercise stress and adaptation. However, the influence of cardiorespiratory fitness on acute hormonal and inflammatory responses to exercise remains incompletely understood.

This study employed a randomized crossover design involving team athletes aged 18-35 years. Participants completed two cycling exercise protocols: a short-term anaerobic test (Wingate) and a long-term aerobic test (YMCA submaximal cycling test). The two testing sessions were separated by a seven-day washout period and were performed at the same time of day to minimize circadian variation.

Saliva samples were collected before exercise, immediately after exercise, and 30 minutes post-exercise. Salivary IL-6 and cortisol concentrations were analyzed to determine acute physiological responses to both exercise modalities. Participants were categorized according to cardiorespiratory fitness level based on estimated VO₂max values, and biomarker responses were compared between fitness groups.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Team athletes aged 18 to 35 years Participation in organized team sports (e.g., volleyball, basketball, soccer, or handball) Minimum of 3 training sessions per week, with each session lasting at least 1 hour Sports participation history of at least 2 years Apparently healthy and free from known cardiovascular, metabolic, endocrine, or respiratory diseases Willingness to provide written informed consent

Exclusion criteria

Current musculoskeletal injury or illness affecting exercise performance Use of medications known to influence hormonal or inflammatory responses Smoking or use of tobacco products Acute infection within the previous two weeks Failure to complete both exercise testing sessions Failure to comply with pre-test instructions

Treatment and study plan

Wingate Anaerobic Cycling Test

Behavioral

Participants performed a 30-second all-out Wingate anaerobic cycling test to evaluate acute physiological responses. Saliva samples were collected before exercise, immediately after exercise, and 30 minutes after exercise for cortisol and interleukin-6 analysis.

Other names: Short-Term Cycling Test

YMCA Submaximal Cycling Test

Behavioral

Participants performed a YMCA submaximal cycling test to assess cardiorespiratory fitness and exercise-induced physiological responses. Saliva samples were collected before exercise, immediately after exercise, and 30 minutes after exercise for cortisol and interleukin-6 analysis.

Primary outcomes

  1. Salivary Cortisol Response

    Time frame: Pre-exercise, immediately post-exercise, and 30 minutes post-exercise

    Change in salivary cortisol concentrations measured before exercise, immediately after exercise, and 30 minutes after exercise following short-term and long-term cycling tests.

Secondary outcomes

  1. Salivary Interleukin-6 (IL-6) Response

    Time frame: Pre-exercise, immediately post-exercise, and 30 minutes post-exercise

    Change in salivary interleukin-6 concentrations measured before exercise, immediately after exercise, and 30 minutes after exercise following short-term and long-term cycling tests.

Sponsors and collaborators

Lead sponsor

Ondokuz Mayıs University

Other

Registry information

Official study title

Interleukin-6 and Cortisol Responses Following Short- and Long-Term Cycling Tests in Team Athletes With Different Cardiorespiratory Fitness Levels

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Jul 2, 2026
Registry last updated
Jul 6, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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