Effect of Training Intensity on Microvascular Function

NCT ID: NCT07237854

Last Updated: 2025-11-20

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 25 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-01-22
• Study Completion Date: 2024-12-31

Brief Summary

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.

Conditions

Vascular Remodeling; Sedentary Behavior; Hemodynamic Rebound

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Moderate-Intensity Continuous Training (MICT): 34 min at 65% maximal heart rate

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.

Group Type: EXPERIMENTAL

Percutaneous muscle biopsies of the vastus lateralis (quadriceps)

Intervention Type: PROCEDURE

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)

Intervention Type: 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)

Intervention Type: 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.

High-Intensity Interval Training (HIIT): 2x2 min at 65% and 90% of maximal heart rate

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.

Group Type: EXPERIMENTAL

Percutaneous muscle biopsies of the vastus lateralis (quadriceps)

Intervention Type: PROCEDURE

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)

Intervention Type: 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)

Intervention Type: 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.

Interventions

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.

Intervention Type: PROCEDURE

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.

Intervention Type: OTHER

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.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Healthy female or male between 18 and 45 years
• Be sedentary
• Able to cycle
• Able to provide written informed consent

Exclusion Criteria

• Have a pathology that may impact vascular function as :

• cardiac pathology
• pneumological pathology
• metabolic pathology
• Smoke

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Université Libre de Bruxelles

OTHER

Sponsor Role: lead

Responsible Party

Emilie Maufroy

Research Scientist, Reasearch Unit in Rehabilitation Sciences

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Université Libre de Bruxelles, Faculté des Sciences de la motricité, Laboratoire de kinésithérapie

Brussels, Anderlecht, Belgium

Countries

Belgium

Other Identifiers

ULB

Identifier Type: -

Identifier Source: org_study_id