Oxidative Stress and Antioxidant Enzyme Activities in Elite Female Turkish Cross-Country Skiers

NCT07181889 | Completed

• 1 other identifier: 27754
• Study Type: observational
• Target: 34
• Locations: 1 country
• Sites: 1

Brief Summary

This study is designed to investigate oxidative stress and antioxidant defense biomarkers in elite female cross-country skiers compared with sedentary women. Oxidative stress plays a central role in exercise adaptation, and the balance between reactive oxygen species production and antioxidant capacity can influence performance and recovery. Despite growing interest in redox biology, evidence from elite female endurance athletes is limited. This cross-sectional observational study enrolled 17 elite female cross-country skiers, who were members of the Turkish national junior and senior teams, and 17 age- and BMI-matched sedentary women. All participants reported to the laboratory between 07:00 and 09:00 a.m. after an overnight fast. Anthropometric characteristics, including height, weight, and BMI, were measured under standardized conditions. Venous blood samples were collected from the antecubital vein using aseptic technique. Serum was separated, stored at -80 °C, and analyzed for key redox biomarkers. Catalase (CAT) activity was measured spectrophotometrically using the method of Aebi, reduced glutathione (GSH) concentration was determined using Ellman's reagent, and malondialdehyde (MDA), a marker of lipid peroxidation, was assessed using the thiobarbituric acid reactive substances (TBARS) assay. All analyses were performed in triplicate in a certified clinical biochemistry laboratory. The primary objective of this study is to characterize and compare systemic antioxidant capacity and oxidative stress levels between trained athletes and sedentary controls. The data generated will provide insight into how chronic endurance training in cold outdoor environments affects enzymatic and non-enzymatic antioxidant systems in young women.

Conditions

Oxidative Stress; Redox Imbalance; Exercise-Induced Physiological Stress

Keywords

Catalase; Glutathione; Malondialdehyde; Oxidative Stress Biomarkers; Endurance Training; Female Athletes; Sports Science

Outcome Measures

Primary Outcomes (3)

• Serum Catalase (CAT) Activity

  Catalase activity in serum measured spectrophotometrically at 240 nm following Aebi's method; expressed as units per milliliter (U/mL).

  Baseline (single fasting blood draw)

• Serum Reduced Glutathione (GSH) Concentration

  Total glutathione concentration measured colorimetrically using Ellman's reagent (DTNB); expressed as µmol/L.

  Baseline (single fasting blood draw)

• Serum Malondialdehyde (MDA) Concentration

  Marker of lipid peroxidation measured via thiobarbituric acid reactive substances (TBARS) method; expressed as nmol/mL.

  Baseline (single fasting blood draw)

Study Arms (2)

Elite Cross-Country Skiers

Female athletes aged 15-20 years who are members of the Turkish junior or senior national cross-country skiing teams. Participants are engaged in regular endurance training and competition. No experimental intervention is applied; participants undergo anthropometric measurements and venous blood sampling for oxidative stress and antioxidant biomarker analysis.

Sedentary Control Group

Healthy women aged 15-20 years, matched for age and BMI to the athlete group. Participants have no history of regular exercise training for at least 6 months prior to enrollment. No experimental intervention is applied; participants undergo the same anthropometric and blood sampling procedures as the athlete group.

Eligibility Criteria

• Age: 15 Years - 20 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

This study included 34 healthy female participants: 17 elite cross-country skiers and 17 sedentary controls matched for age and BMI. All participants were aged 15-20 years and met strict inclusion and exclusion criteria to ensure a homogeneous sample.

You may qualify if:

• Female participants aged 15-20 years
• Members of the Turkish junior or senior national cross-country skiing team (for athlete group)
• Sedentary lifestyle, no regular exercise training within the past 6 months (for control group)
• Body mass index within normal range (18.5-24.9 kg/m²)
• No use of antioxidant or vitamin supplementation within the past 3 months
• Non-smoker and no alcohol consumption
• Voluntary participation with signed informed consent (and parental consent if under 18 years)

You may not qualify if:

• Presence of chronic metabolic, cardiovascular, or inflammatory diseases
• Current medication use affecting oxidative stress or metabolism
• Acute infection or illness within 2 weeks prior to data collection
• Recent musculoskeletal injury or inability to comply with testing procedures
• Failure to complete overnight fasting or rest requirements before blood sampling

Sponsors & Collaborators

• Duvenciler Anadolu Lİsesi: lead

Study Sites (1)

Muş Alparslan University, Faculty of Sports Sciences

Muş, Muş, 49250, Turkey (Türkiye)

Location

Biospecimen

Retention: SAMPLES WITHOUT DNA

Serum samples obtained from fasting venous blood draws will be retained at -80 °C for future biochemical analysis of oxidative stress and antioxidant biomarkers. No genetic or DNA-based testing will be performed.

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: September 12, 2025
• First Posted: September 18, 2025
• Study Start: November 12, 2021
• Primary Completion: February 20, 2022
• Study Completion: February 25, 2022
• Last Updated: September 25, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)