Skip to main content
OpenTrials
Not Yet Recruiting

NCT Number: NCT07469280

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

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.

Not Yet Recruiting

Trial opening soon.

Get Notified

Key information

Conditions

Obesity, Class III Apnea Body Weight Dyssomnias Inspiratory Muscle Training Nervous System Diseases Nutrition Disorders Nutritional and Metabolic Diseases Obesity Obesity, Morbid Overnutrition Overweight Pathological Conditions, Signs and Symptoms Respiration Disorders Respiratory Tract Diseases Signs and Symptoms Sleep Apnea Syndromes Sleep Apnea, Obstructive Sleep Disorders, Intrinsic Sleep Wake Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Santa Catarina State University - CEFID (Center of Health and Sport Sciences)

Florianópolis, Santa Catarina, 88080-350, Brazil

Location contact

Karina Abreu, MSc

CONTACT

[email protected]

+55 (48) 3664-8651

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

High-Intensity Progressive Inspiratory Muscle Training (IMT)

Device

"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."

Primary outcomes

  1. 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)

Secondary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. 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).

  5. 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.

  6. 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Darlan Laurício Matte, PhD

CONTACT

[email protected]

+55 48 3364 8696

Karina Abreu, MSc

CONTACT

[email protected]

+55 (48) 998230417

Sponsors and collaborators

Lead sponsor

University of the State of Santa Catarina

Other

Registry information

Official study title

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

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Mar 13, 2026
Registry last updated
Mar 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.