Hemodynamic Rebound, Sedentary Behavior, Vascular Remodeling
Conditions
Keywords
Microcirculation, Hemodynamic Instability, Microvascular Density, Quadriceps Muscle, Endurance Training, High-Intensity Interval Training
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.
Interventions
PROCEDUREPercutaneous 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.
OTHERMeasurement 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.
OTHERNon-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.
Sponsors
Université Libre de Bruxelles
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Masking description
Participants and the researcher will know the group allocation and therfore cannot be blinded.
Intervention 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.
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percutaneous muscle biopsies of the vastus lateralis | 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 |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cardiopulmonary Exercise Testing (CPET) | At baseline and after completion of the 8-week intervention | 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 : 1. VO₂ (oxygen uptake) in mL/min 2. VCO₂ (carbon dioxide production) in mL/min 3. Minute ventilation (VE) in L/min |
| Maximal Cardiac Output Measurement Using Inert Gas Rebreathing (Innocor) | At baseline and after completion of the 8-week intervention | 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: 1. Cardiac output (L/min) 2. Stroke volume (ml/min) 3. Heart rate (bpm) 4. Pulmonary blood flow (L/min) |
Countries
Belgium
Outcome results
None listed