Vascular RemodelingNCT07237854
Effect of Training Intensity on Microvascular Function
A study testing Percutaneous muscle biopsies of the vastus lateralis (quadriceps), Measurement of the maximal oxygen uptake (VO2max) and Non-Invasive Cardiac Output Measurement (Innocor) in people with Vascular Remodeling and Sedentary Behavior, run by Université Libre de Bruxelles at 1 site in Belgium.
Trial summary
The aim of this trial is to investigate the effect of aerobic training intensity on muscle vascular function: continuous versus interval. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Vascular Remodeling, Sedentary Behavior, Hemodynamic Rebound
- What is being tested?
- Percutaneous muscle biopsies of the vastus lateralis (quadriceps), Measurement of the maximal oxygen uptake (VO2max) and Non-Invasive Cardiac Output Measurement (Innocor)
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- 1 siteBelgium
- Study dates
- 22 Jan 2022to 31 Dec 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy female or male between 18 and 45 years
- Be sedentary
- Able to cycle
- Able to provide written informed consent
Who cannot join
- Have a pathology that may impact vascular function as :
- cardiac pathology
- pneumological pathology
- metabolic pathology
- Smoke
Trial locations and contacts
1 site in 1 country.
Belgium1 site
Université Libre de Bruxelles, Faculté des Sciences de la motricité, Laboratoire de kinésithérapie
Brussels, Anderlecht, 1070
About this study
Official title: Effect of Continuous Versus High-intensity Interval Aerobic Training on the Muscular Vascular Adaptation
The aim of this trial is to investigate the effect of aerobic training intensity on muscle vascular function: continuous versus interval.
Read the detailed description
This trial will compare the hemodynamic effects of aerobic training on muscle microvascular function between participants randomly assigned to one of two groups: a continuous training group and an high-intensity interval training group.
All data concerning the primary and secondary outcomes will be obtained at the start and repeated at the end of 8 weeks aerobic training.
- Conditions
- Vascular Remodeling, Sedentary Behavior, Hemodynamic Rebound
- Being tested
- Percutaneous muscle biopsies of the vastus lateralis (quadriceps), Measurement of the maximal oxygen uptake (VO2max), Non-Invasive Cardiac Output Measurement (Innocor)
- Keywords
- Microcirculation, Hemodynamic Instability, Microvascular Density, Quadriceps Muscle, Endurance Training, High-Intensity Interval Training
- Medical subject headings
- Vascular Remodeling, Sedentary Behavior
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Percutaneous muscle biopsies of the vastus lateralis (quadriceps)Procedure or surgery
Percutaneous muscle biopsies of the vastus lateralis (quadriceps) were performed under local anesthesia. Samples were collected at baseline and/or post-intervention to assess microvascular structure, fiber composition, and molecular adaptations to aerobic training.
Measurement of the maximal oxygen uptake (VO2max)Other
Cardiopulmonary Exercise Testing (CPET) Maximal oxygen consumption (VO₂max) was assessed using an incremental stepwise protocol on a cycle ergometer. Participants performed the test at baseline and after the 8-week training intervention. Respiratory gas exchange was continuously measured using a COSMED K5 portable metabolic system, which provided breath-by-breath analysis of oxygen uptake (VO₂), carbon dioxide production (VCO₂), and ventilation parameters. The test was terminated upon volitional exhaustion or when predefined criteria for VO₂max plateau were met.
Non-Invasive Cardiac Output Measurement (Innocor)Other
Maximal cardiac output was assessed at peak exercise intensity during cardiopulmonary exercise testing (CPET) using the Innocor device. This system employs the inert gas rebreathing technique, which involves the controlled inhalation of a gas mixture containing nitrous oxide (N₂O) and sulfur hexafluoride (SF₆). By analyzing the washout kinetics of these gases during rebreathing, the device estimates pulmonary blood flow, which is then used to calculate cardiac output non-invasively. Measurements were performed at the maximal workload reached during the incremental cycling test.
| Study group | Role | What they receive |
|---|---|---|
| Moderate-Intensity Continuous Training (MICT): 34 min at 65% maximal heart rate | Experimental | Participants performed a 3-minute warm-up at 50% of their maximal heart rate (HRmax), as determined during baseline cardiopulmonary exercise testing (ergospirometry), followed by 40 minutes of continuous cycling at 65% of their VO₂max. Sessions were conducted three times per week for a total duration of 8 weeks. Receives: Procedure: Percutaneous muscle biopsies of the vastus lateralis (quadriceps); Other: Measurement of the maximal oxygen uptake (VO2max); Other: Non-Invasive Cardiac Output Measurement (Innocor) |
| High-Intensity Interval Training (HIIT): 2x2 min at 65% and 90% of maximal heart rate | Experimental | Participants performed a 3-minute warm-up at 50% of their maximal heart rate (HRmax), as determined during baseline cardiopulmonary exercise testing (ergospirometry). The main training protocol consisted of alternating 2-minute cycling bouts: 2 minutes at 65% HRmax followed by 2 minutes at 90% HRmax, repeated continuously for a total of 28 minutes. Sessions were conducted three times per week over an 8-week period. Receives: Procedure: Percutaneous muscle biopsies of the vastus lateralis (quadriceps); Other: Measurement of the maximal oxygen uptake (VO2max); Other: Non-Invasive Cardiac Output Measurement (Innocor) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percutaneous muscle biopsies of the vastus lateralis
Muscle tissue samples obtained from the vastus lateralis were processed using optical clearing and immunohistochemical staining techniques to visualize the microvascular network. Confocal microscopy was employed to acquire high-resolution three-dimensional images of arterioles, capillaries, and venules. Quantitative assessments included:
- Internal diameter measurements, based on endothelial cell boundaries (intima layer)
- External diameter measurements, based on smooth muscle cells and pericytes (media layer)
- Capillary density, determined by counting the number of capillaries per sample volume
Measured: At baseline and after completion of the 8-week intervention
Secondary outcomes (2)
Cardiopulmonary Exercise Testing (CPET)
VO₂max was determined using a graded, incremental exercise test performed on a cycle ergometer until volitional exhaustion. Throughout the test, respiratory gases were continuously measured using a metabolic cart (e.g., COSMED K5), which provided breath-by-breath analysis.
The following parameters were recorded :
- VO₂ (oxygen uptake) in mL/min
- VCO₂ (carbon dioxide production) in mL/min
- Minute ventilation (VE) in L/min
Measured: At baseline and after completion of the 8-week intervention
Maximal Cardiac Output Measurement Using Inert Gas Rebreathing (Innocor)
Innocor is a medical device that estimates cardiac output using the inert gas rebreathing technique, a validated non-invasive method. During the procedure, the participant inhales a gas mixture containing nitrous oxide (N₂O) and sulfur hexafluoride (SF₆) through a closed circuit. These inert gases are absorbed and eliminated at rates proportional to pulmonary blood flow. By analyzing the washout kinetics of these gases during a brief rebreathing period, Innocor calculates pulmonary blood flow, which is then used to estimate cardiac output. This measurement is typically performed at rest or at peak exercise intensity, such as during the final stage of a cardiopulmonary exercise test (CPET).
The system provides real-time data on:
- Cardiac output (L/min)
- Stroke volume (ml/min)
- Heart rate (bpm)
- Pulmonary blood flow (L/min)
Measured: At baseline and after completion of the 8-week intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Nov 2025
- Study start22 Jan 2022
- Primary completion15 Aug 2024
- Study completion31 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Vascular RemodelingStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- A parallel group randomised controlled trial will be used to determine the superiority of high-intensity interval training versus continuous training on the improvement of quadricpes microvascular function.
- Masking
- None (open label)
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- Université Libre de Bruxelles
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Emilie Maufroy, Université Libre de Bruxelles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07237854
- Sponsor's protocol ID
- ULB
- Status last verified
- Oct 2025
- First submitted
- 26 Sep 2022
- Last updated
- 20 Nov 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Maufroy E, Rigaut C, Maufroy C, Baeyens N, Deboeck G. Vascular remodeling enhances high-flow muscle oxygen delivery following aerobic exercise training. Front Physiol. 2026 Jul 1;17:1840439. doi: 10.3389/fphys.2026.1840439. eCollection 2026.
PubMed 42460304
Study at a glance
From the registry record, last updated by the sponsor on 20 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Continuous Versus High-intensity Interval Aerobic Training on the Muscular Vascular Adaptation
- ClinicalTrials.gov ID
- NCT07237854
- Acronym / sponsor ID
- ULB
- Conditions
- Vascular Remodeling, Sedentary Behavior, Hemodynamic Rebound
- Keywords
- Microcirculation, Hemodynamic Instability, Microvascular Density, Quadriceps Muscle, Endurance Training, High-Intensity Interval Training
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 25 participants (actual)
- Lead sponsor
- Université Libre de BruxellesUniversity, hospital or other
- Study start
- 22 Jan 2022 (actual)
- Primary completion
- 15 Aug 2024 (actual)
- Study completion
- 31 Dec 2024 (actual)
- First posted
- 20 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this trial is to investigate the effect of aerobic training intensity on muscle vascular function: continuous versus interval.
Detailed description
This trial will compare the hemodynamic effects of aerobic training on muscle microvascular function between participants randomly assigned to one of two groups: a continuous training group and an high-intensity interval training group.
All data concerning the primary and secondary outcomes will be obtained at the start and repeated at the end of 8 weeks aerobic training.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- A parallel group randomised controlled trial will be used to determine the superiority of high-intensity interval training versus continuous training on the improvement of quadricpes microvascular function.
| Arm | Type | Receives |
|---|---|---|
| Moderate-Intensity Continuous Training (MICT): 34 min at 65% maximal heart rate | Experimental | Procedure: Percutaneous muscle biopsies of the vastus lateralis (quadriceps), Other: Measurement of the maximal oxygen uptake (VO2max), Other: Non-Invasive Cardiac Output Measurement (Innocor)Participants performed a 3-minute warm-up at 50% of their maximal heart rate (HRmax), as determined during baseline cardiopulmonary exercise testing (ergospirometry), followed by 40 minutes of continuous cycling at 65% of their VO₂max. Sessions were conducted three times per week for a total duration of 8 weeks. |
| High-Intensity Interval Training (HIIT): 2x2 min at 65% and 90% of maximal heart rate | Experimental | Procedure: Percutaneous muscle biopsies of the vastus lateralis (quadriceps), Other: Measurement of the maximal oxygen uptake (VO2max), Other: Non-Invasive Cardiac Output Measurement (Innocor)Participants performed a 3-minute warm-up at 50% of their maximal heart rate (HRmax), as determined during baseline cardiopulmonary exercise testing (ergospirometry). The main training protocol consisted of alternating 2-minute cycling bouts: 2 minutes at 65% HRmax followed by 2 minutes at 90% HRmax, repeated continuously for a total of 28 minutes. Sessions were conducted three times per week over an 8-week period. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Healthy female or male between 18 and 45 years
- Be sedentary
- Able to cycle
- Able to provide written informed consent
Key exclusion criteria (5 listed)
- Have a pathology that may impact vascular function as :
- Smoke
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Percutaneous muscle biopsies of the vastus lateralis (quadriceps)Percutaneous muscle biopsies of the vastus lateralis (quadriceps) were performed under local anesthesia. Samples were collected at baseline and/or post-intervention to assess microvascular structure, fiber composition, and molecular adaptations to aerobic training. | Procedure or surgery | High-Intensity Interval Training (HIIT): 2x2 min at 65% and 90% of maximal heart rate, Moderate-Intensity Continuous Training (MICT): 34 min at 65% maximal heart rate |
| Measurement of the maximal oxygen uptake (VO2max)Cardiopulmonary Exercise Testing (CPET) Maximal oxygen consumption (VO₂max) was assessed using an incremental stepwise protocol on a cycle ergometer. Participants performed the test at baseline and after the 8-week training intervention. Respiratory gas exchange was continuously measured using a COSMED K5 portable metabolic system, which provided breath-by-breath analysis of oxygen uptake (VO₂), carbon dioxide production (VCO₂), and ventilation parameters. The test was terminated upon volitional exhaustion or when predefined criteria for VO₂max plateau were met. | Other | High-Intensity Interval Training (HIIT): 2x2 min at 65% and 90% of maximal heart rate, Moderate-Intensity Continuous Training (MICT): 34 min at 65% maximal heart rate |
| Non-Invasive Cardiac Output Measurement (Innocor)Maximal cardiac output was assessed at peak exercise intensity during cardiopulmonary exercise testing (CPET) using the Innocor device. This system employs the inert gas rebreathing technique, which involves the controlled inhalation of a gas mixture containing nitrous oxide (N₂O) and sulfur hexafluoride (SF₆). By analyzing the washout kinetics of these gases during rebreathing, the device estimates pulmonary blood flow, which is then used to calculate cardiac output non-invasively. Measurements were performed at the maximal workload reached during the incremental cycling test. | Other | High-Intensity Interval Training (HIIT): 2x2 min at 65% and 90% of maximal heart rate, Moderate-Intensity Continuous Training (MICT): 34 min at 65% maximal heart rate |
Primary outcome
Percutaneous muscle biopsies of the vastus lateralis
Time frame: At baseline and after completion of the 8-week intervention
Muscle tissue samples obtained from the vastus lateralis were processed using optical clearing and immunohistochemical staining techniques to visualize the microvascular network. Confocal microscopy was employed to acquire high-resolution three-dimensional images of arterioles, capillaries, and venules. Quantitative assessments included: 1. Internal diameter measurements, based on endothelial cell boundaries (intima layer) 2. External diameter measurements, based on smooth muscle cells and pericytes (media layer) 3. Capillary density, determined by counting the number of capillaries per sample volume
2 secondary outcomes
Cardiopulmonary Exercise Testing (CPET)
Time frame: At baseline and after completion of the 8-week intervention
Maximal Cardiac Output Measurement Using Inert Gas Rebreathing (Innocor)
Time frame: At baseline and after completion of the 8-week intervention
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Nov 2025.
- Derived from this study: PubMed 42460304Maufroy E, Rigaut C, Maufroy C, Baeyens N, Deboeck G. Vascular remodeling enhances high-flow muscle oxygen delivery following aerobic exercise training. Front Physiol. 2026 Jul 1;17:1840439. doi: 10.3389/fphys.2026.1840439. eCollection 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Percutaneous muscle biopsies of the vastus lateralis (quadriceps), Measurement of the maximal oxygen uptake (VO2max) and Non-Invasive Cardiac Output Measurement (Innocor) in people with Vascular Remodeling and Sedentary Behavior, run by Université Libre de Bruxelles at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 20 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percutaneous muscle biopsies of the vastus lateralis (time frame: At baseline and after completion of the 8-week intervention). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07237854, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Nov 2025.