IL-6 and Cortisol Responses to Cycling Exercise

June 26, 2026 updated by: Eda Karaduman, Ondokuz Mayıs University

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

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Actual)

27

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Samsun
      • Samsun, Samsun, Turkey (Türkiye), 55139
        • Ondokuz Mayis University Faculty of Sport Sciences

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

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 for at least 1 hour per session. 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Long-Term Cycling Test
Participants performed a YMCA submaximal cycling test to assess cardiorespiratory fitness. Saliva samples were collected before exercise, immediately after exercise, and 30 minutes after exercise for the assessment of cortisol and interleukin-6 responses.
Behavioral: YMCA Submaximal Cycling Test
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.
Experimental: Short-Term Cycling Test
Participants performed a 30-second Wingate anaerobic cycling test. Saliva samples were collected before exercise, immediately after exercise, and 30 minutes after exercise for the assessment of cortisol and interleukin-6 responses.
Behavioral: Wingate Anaerobic Cycling Test
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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Pre-exercise, immediately post-exercise, and 30 minutes post-exercise

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Pre-exercise, immediately post-exercise, and 30 minutes post-exercise

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ondokuz Mayıs University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 5, 2025

Primary Completion (Actual)

June 5, 2025

Study Completion (Actual)

June 5, 2025

Study Registration Dates

First Submitted

June 26, 2026

First Submitted That Met QC Criteria

June 26, 2026

First Posted (Actual)

July 2, 2026

Study Record Updates

Last Update Posted (Actual)

July 2, 2026

Last Update Submitted That Met QC Criteria

June 26, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • OMU-IL6-CORT-2024-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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