Metabolic and Nutritional Responses to Acute High-intensity Interval Exercise Performed Under Hypoxic vs. Normoxic Conditions at Matched External Workload in Adults With Overweight and Obesity. (HYPOXHIIT)

September 5, 2026 updated by: Laboratoire des Adaptations Métaboliques à l'Exercice en conditions Physiologiques et Pathologiques

Comparison of HIIT Exercise Under Hypoxic and Normoxic Conditions in Adults With Overweight or Obesity: Impact on Oxygen Consumption, Carbohydrate and Lipid Substrate Utilization, and Appetite During Recovery.

Obesity management involves lifestyle and dietary measures that include appropriate nutrition and increased physical activity (PA). Among the various PA options available, HIIT (High-Intensity Interval Training) workouts are now recognized as fun and effective programs for promoting fat loss. To date, in overweight or obese individuals, only two studies mention the benefits of HIIT performed under hypoxia for modulating body composition, and more specifically, reducing the amount of adipose tissue. These studies hypothesize an increased energy expenditure under hypoxia associated with a transient loss of appetite. In order, to further investigate the adaptations following HIIT under hypoxia versus normoxia, we propose to compare, in acute conditions, two HIIT sessions (simulated hypoxia-normobaric vs. normoxia) in overweight or obese subjects. The objective of this assessment is to compare, during exercise and recovery (+2h), oxygen consumption, corresponding energy expenditure, and carbohydrate and lipid utilization in hypoxic versus normoxic conditions. Given the potential influence of hypoxia on appetite, spontaneous food intake and energy expenditure post-24h will also be measured. Finally, since pleasure and perceived exertion are key parameters in adherence to an adapted physical activity (APA) program, these two concepts will also be evaluated through the subjects' experiences.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Obesity management involves lifestyle and dietary measures that include appropriate nutrition and increased physical activity (PA). Among the various PA options available, High-intensity interval training (HIIT) is now recognized as a well-tolerated, safe, and effective exercise modality for improving body composition. In 2016, our pioneering study demonstrated that HIIT is more effective than moderate-intensity continuous training (MICT) in inducing abdominal fat loss in postmenopausal women. A subsequent meta-analysis, conducted by our team in 2018 and encompassing 39 articles involving 617 participants, confirmed the significant effects of HIIT on reducing total and abdominal fat mass in overweight or obese individuals More recently, our work has shown significant results from HIIT + resistance training or HIIT cycling vs. running on improving body composition, and more specifically on reducing abdominal and visceral fat mass, in overweight or obese subjects.

With a focus on performance, HIIT has been combined with simulated hypoxia to maximize training adaptations, particularly to improve cardiovascular, respiratory, circulatory, hematological, and metabolic capacities at the muscular level. Live Low Train High (LLTH) allows athletes to maintain normoxia while being exposed to acute periods of hypoxia during training via hypoxic chambers (simulated altitude). More recently, research has explored the effects of HIIT under hypoxic conditions in patients with metabolic disorders and/or physical deconditioning, focusing primarily on cardiovascular and ventilatory adaptations. To date, in overweight or obese individuals, only three studies investigated the benefit of HIIT under simulated hypoxia for modulating body composition, and more specifically for reducing total or abdominal fat. These studies generally hypothesize a higher energy expenditure during hypoxia, associated with a transient loss of appetite that may be linked to hormonal disturbances, central nervous system adaptability, or metabolic flexibility altering hunger and satiety signals.

In parallel with these hypotheses, hypoxia stimulates HIF-1 production, thus promoting a shift from oxidative metabolism to glycolysis. At the same external mechanical load, the increased use of carbohydrates via glycolysis, combined with increased cardiovascular stress, should promote, during the recovery phase, greater oxygen consumption and lipid oxidation following a hypoxic session. To date, no study has yet evaluated these hypotheses by comparing these parameters following two acute HIIT sessions performed under normoxia or hypoxia.

The aim is to compare the influence of these two sessions on oxygen consumption, the corresponding energy expenditure, and carbohydrate and lipid utilization during recovery (+2h). Given the potential influence of hypoxia on appetite, food intake and spontaneous energy expenditure post-24h will also be measured. Finally, since enjoyment and perceived exertion are crucial parameters for adherence to an adapted physical activity (APA) program, these two concepts will also be assessed through the participants' experiences.

The authors propose the following hypotheses:

Main hypothesis:

  1. Lipid oxidation (g/min) during recovery (+2h) will be higher post-hypoxic session.

    Secondary hypotheses:

  2. Oxygen consumption and energy expenditure will be increased during post-hypoxic session recovery.

4/ Energy intake from the post-exercise meal may be lower post-hypoxic condition.

5/ The effort will be perceived as slightly more difficult in hypoxia due to increased cardiovascular demand.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
18

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • France
    • Allier
      • Bellerive-sur-Allier, Allier, France, 03321
        • CREPS Auvergne Rhône-Alpes / Vichy

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

- overweight or obesity (BMI between 25 kg/m2 and 35 kg/m2)

Exclusion Criteria:

  • medical contraindications to intense physical activity
  • taking ß-blocker
  • diabete
  • women taking hormonal replacement therapy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Non-Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: High Intensity Interval Exercise - Normoxia
HIIE in normoxia
Other: HIIE - Normoxia
Cycling HIIE in Normoxia: 60 x [8 seconds at a power equivalent to 80-85% of HRmax followed by 12 seconds of active recovery at a power equivalent to 40% of HRmax]
Experimental: High Intensity Interval Exercise - Hypoxia
HIIE in hypoxia
Other: HIIE - Hypoxia
Cycling HIIE in Hypoxia (FiO2: 15%): 60 x [8 seconds at a power equivalent to 80-85% of HRmax followed by 12 seconds of active recovery at a power equivalent to 40% of HRmax]

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Lipid oxidation after the exercise session (nromoxia and hypoxia).
Time Frame: Measurement during two hours after the end of the exercise
Determination of lipid and carbohydrate oxidation after the exercise (HIIE normoxia and hypoxia). Lipid aoxidation is measured from oxygen and carbon dioxide consumption (Metamax 3D Cortex).
Measurement during two hours after the end of the exercise

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Oxygen consumption during the recovery period
Time Frame: Two hours after the end of the exercise
Determination of oxygen consumption 2 hours after the exercise session (HIIE normoxia and hypoxia). Determination from Metamax (3D Cortex).
Two hours after the end of the exercise
Energy intakes 24 hours after the exercise
Time Frame: 24 hours post exercise
Evaluation of energy intakes after the exercise session (HIIE normoxia and HIIE hypoxia) during 24 hours (from questionnaires)
24 hours post exercise
Appetite
Time Frame: Before exercise and after exercise (+0 min, +60 min, and +120 min).
Feelings of appetite are measured using a visual appetite scale immediately before and after exercise (+0 min, +60 min, and +120 min).
Before exercise and after exercise (+0 min, +60 min, and +120 min).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Laboratoire des Adaptations Métaboliques à l'Exercice en conditions Physiologiques et Pathologiques

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
CREPS Vichy Auvergne

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 5, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 5, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 11, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 11, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB00012476-2024-23-09-342

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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