High-Intensity Progressive Inspiratory Muscle Training in Class III Obesity and Obstructive Sleep Apnea

March 18, 2026 updated by: Karina Abreu, University of the State of Santa Catarina

High-Intensity Progressive Inspiratory Muscle Training in Class III Obesity and Obstructive Sleep Apnea: Study Protocol for a Prospective Nonconcurrent Multiple-Baseline Single-Case Experimental Design With Stability-Based Phase Transition

The purpose of this study is to evaluate the feasibility and effects of a 12-week high-intensity progressive Inspiratory Muscle Training (IMT) program in individuals with Class III obesity (BMI ≥ 40 kg/m²) and obstructive sleep apnea (OSA). Using a single-case experimental design (SCED) with multiple baselines, the study will investigate whether this respiratory intervention can reduce the severity of sleep apnea, as measured by the Apnea-Hypopnea Index (AHI), and improve inspiratory muscle strength and sleep quality. Participants will perform daily training sessions using a resistive loading device (POWERbreathe), with intensity progressing from 40% to 90% of their maximum inspiratory pressure.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

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.

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 (Estimated)

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.
10

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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Brazil
    • Santa Catarina
      • Florianópolis, Santa Catarina, Brazil, 88080-350
        • Santa Catarina State University - CEFID (Center of Health and Sport Sciences)
        • Contact:

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: -Adults (≥18 years).

  • Of both genders.
  • Class III obesity (BMI > 40 kg/m²).
  • Diagnosis of OSA.
  • Without neurological conditions that would prevent them from responding to the study assessments.

Exclusion Criteria:

  • Systemic diseases (pulmonary, cardiac or renal).
  • Are using medications that may affect muscle performance.
  • Are currently using CPAP therapy.
  • Conditions that could compromise adherence to the study protocol.

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: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

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: Experimental Group: High-Intensity IMT
Participants will undergo a progressive high-intensity Inspiratory Muscle Training (IMT) program using a resistive loading device (POWERbreathe).
Device: High-Intensity Progressive Inspiratory Muscle Training (IMT)
"The intervention consists of 12 weeks of inspiratory muscle training performed 5 days per week. Each session includes 30 breaths through a resistive loading device (POWERbreathe). The training intensity starts at 40% of the Maximum Inspiratory Pressure (MIP) and progressively increases to 90% of MIP. Training load is adjusted weekly based on new MIP measurements to ensure high-intensity stimulus. Compliance and adverse events will be monitored through a training diary."

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
Apnea-Hypopnea Index (AHI)
Time Frame: Baseline (Phase A - three measurements) and Post-Intervention (Phase B - 12th week).
Number of apnea and hypopnea events per hour of sleep, measured via portable polygraphy (Type III)
Baseline (Phase A - three measurements) and Post-Intervention (Phase B - 12th week).

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
Maximum Inspiratory Pressure (MIP)
Time Frame: Weekly assessments throughout Phase A (3 to 5 weeks) and Phase B (12 weeks).
Assessment of inspiratory muscle strength using a digital pressure manometer.
Weekly assessments throughout Phase A (3 to 5 weeks) and Phase B (12 weeks).
Epworth Sleepiness Scale (ESS) score
Time Frame: Baseline and Post-Intervention (12th week).
Validated questionnaire to assess the level of daytime sleepiness. Scores range from 0 to 24, where higher scores indicate greater sleepiness.
Baseline and Post-Intervention (12th week).
Pittsburgh Sleep Quality Index (PSQI) global score
Time Frame: Baseline and Post-Intervention (12th week).
Questionnaire to assess sleep quality over a one-month period. Scores range from 0 to 21; higher scores indicate poorer sleep quality.
Baseline and Post-Intervention (12th week).
International Physical Activity Questionnaire (IPAQ) - Short Form
Time Frame: Baseline and Post-Intervention (12th week).
Assessment of physical activity level. It classifies participants as sedentary, irregularly active, active, or very active based on metabolic equivalent task (MET-min/week).
Baseline and Post-Intervention (12th week).
Borg Rating of Perceived Exertion (RPE)
Time Frame: Daily during the 12 weeks of intervention (Phase B).
Scale ranging from 6 to 20 used to monitor the intensity of the respiratory effort during the IMT sessions.
Daily during the 12 weeks of intervention (Phase B).
Quebec Sleep Questionnaire (QSQ)
Time Frame: Baseline (Phase A) and Post-Intervention (12th week of Phase B).
A disease-specific quality of life questionnaire for obstructive sleep apnea. It consists of 32 items divided into five domains: daytime sleepiness, diurnal symptoms, nocturnal symptoms, emotions, and social interactions. Each item is scored on a 7-point Likert scale, where higher scores indicate better quality of life.
Baseline (Phase A) and Post-Intervention (12th week of Phase B).

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.
University of the State of Santa Catarina

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Darlan Laurício Matte, PhD, Santa Catarina State University (UDESC)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

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.
May 1, 2026

Primary Completion (Estimated)

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.
May 1, 2027

Study Completion (Estimated)

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.
December 1, 2027

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).
March 9, 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.
March 9, 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.
March 13, 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.
March 23, 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.
March 18, 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.
March 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.
  • CAAE86299625.1.0000.0118

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings