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VO2max and Substrate Crossover Point (VO2MAX-CROSS)

2026年8月28日 更新者：Celil Kaçoğlu

Higher VO2max Delays Substrate Switching and Shifts the Crossover Point to Greater Oxygen Uptake During Incremental Exerciseebys

This study aims to investigate the relationship between maximal oxygen uptake (VO2max) and the substrate crossover point during incremental exercise. A total of 20 physical education students are recruited to complete a maximal incremental treadmill test using the standard Bruce protocol. Indirect calorimetry is utilized to assess oxygen uptake (VO2), carbon dioxide production (VCO2), and energy substrate utilization patterns. The substrate crossover point is operationally defined at a respiratory exchange ratio (RER) threshold of 0.85, indicating the metabolic transition toward predominant carbohydrate oxidation. The primary objective is to evaluate how variations in aerobic capacity influence the timing, oxygen uptake, and heart rate (HR) responses at this metabolic transition threshold.

調査の概要

状態

完了

条件

介入・治療

詳細な説明

This study evaluates the relationship between maximal oxygen uptake (VO2max) and the substrate crossover point during incremental treadmill exercise in young, physically active individuals. Substrate utilization kinetics and metabolic flexibility represent critical components of cardiovascular conditioning and endurance performance; however, the impact of continuous variations in aerobic capacity on the onset of metabolic transition requires detailed investigation.

Participants undergo anthropometric testing followed by a maximal graded exercise test on a motor-driven treadmill following the standard Bruce protocol. Breath-by-breath expired gas analysis using indirect calorimetry continuously monitors oxygen uptake (VO2), carbon dioxide production (VCO2), and minute ventilation (VE) throughout the test. Respiratory exchange ratio (RER) values are calculated continuously. The substrate crossover point is operationally defined as the exercise intensity corresponding to an RER threshold of 0.85, representing the metabolic transition where carbohydrate oxidation becomes the predominant contributor to total energy expenditure over lipid oxidation.

Key outcome measures extracted at this threshold include:

Time to reach the crossover point (minutes)

Absolute oxygen uptake at crossover (liters per minute [L/min])

Relative oxygen uptake at crossover (milliliters per kilogram per minute [mL/kg/min])

Percentage of maximal oxygen uptake at crossover (%VO2max)

Heart rate at crossover (beats per minute [bpm])

Statistical associations between maximal aerobic capacity (VO2max) and the primary outcome measures at the crossover point are analyzed using linear correlation and regression models to determine how cardiorespiratory fitness alters substrate switching kinetics under progressive physical strain.

研究の種類

介入

入学 (実際)

20

段階

  • 適用できない

連絡先と場所

このセクションには、調査を実施する担当者の連絡先の詳細と、この調査が実施されている場所に関する情報が記載されています。

研究場所

  • トルコ（Türkiye）
    • Tepebaşi
      • Eskişehir、Tepebaşi、トルコ（Türkiye）、26100
        • Eskişehir Technical University

参加基準

研究者は、適格基準と呼ばれる特定の説明に適合する人を探します。これらの基準のいくつかの例は、人の一般的な健康状態または以前の治療です。

適格基準

就学可能な年齢

  • 大人

健康ボランティアの受け入れ

はい

説明

Inclusion Criteria:

  • Healthy male or female physical education students aged 18 to 30 years
  • Regularly physically active (participating in structured physical activity at least 3 days per week)
  • Medically cleared and capable of performing maximal graded treadmill exercise testing to voluntary exhaustion
  • Willing and able to provide written informed consent

Exclusion Criteria:

  • History of cardiovascular, pulmonary, metabolic, renal, or neuromuscular disorders
  • Acute musculoskeletal injury or orthopedic condition that impairs treadmill running or maximal exertion
  • Current use of prescription medications, stimulants, or dietary supplements known to alter metabolic rate, heart rate, or substrate oxidation
  • Use of tobacco, nicotine products, or alcohol within 24 hours prior to testing
  • Consumption of caffeine or vigorous physical exercise within 24 hours prior to the exercise trial

研究計画

このセクションでは、研究がどのように設計され、研究が何を測定しているかなど、研究計画の詳細を提供します。

研究はどのように設計されていますか？

デザインの詳細

  • 主な目的：基礎科学
  • 割り当て：なし
  • 介入モデル：単一グループの割り当て
  • マスキング：なし（オープンラベル）

武器と介入

参加者グループ / アーム
介入・治療
実験的：Exercise Testing Group
: Healthy young adult participants who undergo a single maximal incremental treadmill exercise test using the Bruce Protocol to assess cardiorespiratory fitness (VO2max) and substrate crossover kinetics.
行動：Incremental Graded Exercise Test (Bruce Protocol)
Participants perform a maximal treadmill exercise test following the standardized Bruce Protocol. The test begins with a warm-up, followed by progressive 3-minute stages with continuous increases in speed and incline until voluntary exhaustion. Indirect calorimetry is used continuously via breath-by-breath gas analysis to measure VO2VCO2, and RER for substrate crossover determination.
他の名前：
  • Bruce Treadmill Protocol
  • Maximal Incremental Exercise Test
  • Graded Exercise Testing (GXT)
  • Maximal Treadmill Exercise Test

この研究は何を測定していますか？

主要な結果の測定

結果測定
メジャーの説明
時間枠
Time to reach the substrate crossover point
時間枠：Time Frame: Baseline (single test session, Day 1)

Measure Description: Elapsed time (in minutes) from the start of the incremental treadmill test (Bruce protocol) to the point where the respiratory exchange ratio (RER) reaches 0.85, indicating the metabolic crossover where carbohydrate oxidation becomes the predominant fuel source.

Time Frame: Baseline (single exercise test session, Day 1) Unit of Measure: Minutes
Time Frame: Baseline (single test session, Day 1)
Relative oxygen uptake at the crossover point
時間枠：Measure Description: Measured continuously during the incremental exercise test using indirect calorimetry, recorded specifically at the point where the respiratory exchange ratio (RER) reaches 0.85. Time Frame: Baseline

Measure Title: Relative oxygen uptake at the substrate crossover point Measure Description: Oxygen uptake (VO2) normalized to body weight (mL/kg/min) recorded at the moment the substrate crossover point (respiratory exchange ratio [RER] = 0.85) is reached during the maximal incremental treadmill test (Bruce protocol).

Time Frame: Baseline
Measure Description: Measured continuously during the incremental exercise test using indirect calorimetry, recorded specifically at the point where the respiratory exchange ratio (RER) reaches 0.85. Time Frame: Baseline

二次結果の測定

結果測定
メジャーの説明
時間枠
Percentage of VO2max at the crossover point
時間枠：Measure Description: Relative oxygen uptake (VO2) at the substrate crossover point (respiratory exchange ratio [RER] = 0.85) expressed as a % of the participant's maximal oxygen uptake (VO2max), calculated upon completion of the Bruce protocol

Measure Title: Percentage of maximal oxygen uptake at the substrate crossover point

Measure Description: Relative oxygen uptake (VO2) at the substrate crossover point (respiratory exchange ratio [RER] = 0.85) expressed as a percentage (%) of the participant's maximal oxygen uptake (VO2max) during the Bruce protocol treadmill test.

Time Frame: Baseline
Measure Description: Relative oxygen uptake (VO2) at the substrate crossover point (respiratory exchange ratio [RER] = 0.85) expressed as a % of the participant's maximal oxygen uptake (VO2max), calculated upon completion of the Bruce protocol
Heart rate at the crossover point
時間枠：Measure Description: Heart rate (HR) in beats per minute (bpm) measured continuously during the incremental treadmill test (Bruce protocol), recorded at the substrate crossover threshold (respiratory exchange ratio [RER] = 0.85). Time Frame: Baseline

Measure Title: Heart rate at the substrate crossover point Measure Description: Heart rate (HR) recorded in beats per minute (bpm) using a telemetric heart rate monitor at the point where the substrate crossover threshold (respiratory exchange ratio [RER] = 0.85) is achieved during the maximal incremental treadmill test (Bruce protocol).

Time Frame: Baseline
Measure Description: Heart rate (HR) in beats per minute (bpm) measured continuously during the incremental treadmill test (Bruce protocol), recorded at the substrate crossover threshold (respiratory exchange ratio [RER] = 0.85). Time Frame: Baseline
Maximal oxygen consumption (VO2max)
時間枠：Measure Description: Relative maximal oxygen uptake (VO2max in mL/kg/min) assessed at maximal exertion at the end of the Bruce protocol treadmill test to voluntary exhaustion via indirect calorimetry. Time Frame: Baseline

Measure Description:

The highest rate of relative oxygen uptake (VO2 in mL/kg/min) attained during the maximal graded exercise test (Bruce protocol) to voluntary exhaustion via indirect calorimetry.

Time Frame: Baseline
Measure Description: Relative maximal oxygen uptake (VO2max in mL/kg/min) assessed at maximal exertion at the end of the Bruce protocol treadmill test to voluntary exhaustion via indirect calorimetry. Time Frame: Baseline

協力者と研究者

ここでは、この調査に関係する人々や組織を見つけることができます。

スポンサー

Celil Kaçoğlu

捜査官

  • 主任研究者：celil kaçoğlu, Ph.D.、Eskişehir Teknik Üniversitesi

出版物と役立つリンク

研究に関する情報を入力する責任者は、自発的にこれらの出版物を提供します。これらは、研究に関連するあらゆるものに関するものである可能性があります。

一般刊行物

研究記録日

これらの日付は、ClinicalTrials.gov への研究記録と要約結果の提出の進捗状況を追跡します。研究記録と報告された結果は、国立医学図書館 (NLM) によって審査され、公開 Web サイトに掲載される前に、特定の品質管理基準を満たしていることが確認されます。

主要日程の研究

研究開始 (実際)

2026年5月1日

一次修了 (実際)

2026年6月30日

研究の完了 (実際)

2026年7月15日

試験登録日

最初に提出

2026年8月25日

QC基準を満たした最初の提出物

2026年8月28日

最初の投稿 (実際)

2026年9月2日

学習記録の更新

投稿された最後の更新 (実際)

2026年9月2日

QC基準を満たした最後の更新が送信されました

2026年8月28日

最終確認日

2026年8月1日

詳しくは

本研究に関する用語

キーワード

その他の研究ID番号

  • EskisehirTU-SBF-CK-04

個々の参加者データ (IPD) の計画

個々の参加者データ (IPD) を共有する予定はありますか?

いいえ

IPD プランの説明

Individual participant data will not be publicly shared due to privacy and ethical constraints aimed at protecting participant confidentiality. However, de-identified aggregated data or specific data sets may be made available from the corresponding author upon reasonable academic request.

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