High-intensity Inspiratory Muscle Training as a Pre-cardiac Rehabilitation in Heart Disease

January 16, 2026 updated by: University of Illinois at Chicago

Effects of High-intensity Inspiratory Muscle Training as a Pre-cardiac Rehabilitation Intervention on Cardiovascular Functions in Patients With Heart Disease

Background/aim: Endothelial function is closely associated with coronary artery health among individuals being treated for heart disease. An impairment in endothelial function promotes arterial stiffening that directly contributes to elevated systolic blood pressure as a result of increased vascular resistance. Inspiratory muscle training is simply a form of training consisting of repeated inspirations against resistance. Inspiratory muscle training has also been applied to patients with chronic disease or as an additional therapy for cardiac rehabilitation and it has proven to be safe in these groups. Few studies in the literature examined the effects of high-intensity inspiratory muscle training in this population, however, these studies did not examine the direct effects of inspiratory muscle training on vascular function. To the best of our knowledge, the effects of inspiratory muscle training in patients with heart disease on endothelial function and arterial stiffness prior to starting cardiac rehabilitation have not been investigated. This study aims to investigate and interpret whether high-intensity inspiratory muscle training, beyond the usual care of heart disease, improves endothelial function and arterial stiffness.

Methods: The study was designed as a randomized controlled trial. Patients will be allocated for inspiratory muscle training (IMT) with 60% of maximum inspiratory pressure (MIP) or sham inspiratory muscle training (Sham-control), for 4 weeks. In both groups, before and after 4-week training, cardiovascular functions will be measured and compared.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Background: Cardiovascular diseases (CVD) remain a leading cause of morbidity and mortality in both men and women in developed and developing societies (Joseph et al., 2017). Some degree of pulmonary dysfunction is highly likely in patients with heart disease compared to those without(Calles et al., 2016; Cahalin and Arena, 2015). This can affect pulmonary function, and gas exchange, as well as decrease maximum inspiratory and expiratory pressures (MIP and MEP, respectively)(Dos Santos et al., 2019; Haeffener et al., 2008; Roncada et al., 2015; Cahalin and Arena, 2015).

Inspiratory muscle training has been shown to be an effective form of training that enhances lung function. It consists of repetitive breath cycles where one inspires against resistance placed by a device and expires against no resistance. Studies that have applied this form of training in patients with heart disease have found significant improvements in MIP-MEP, tidal volume, vital capacity, and 6-minute walking distance. Few studies have examined the effects of high-intensity (between 50-80% of MIP) inspiratory muscle training in patients with heart disease (Dos Santos et al., 2019; Dos Santos et al., 2021; Laoutaris et al., 2007; Miozzo et al., 2018; Sadek et al., 2022). This level of training has been associated with greater improvements in the aferomentioned outcomes of interest, however, no study has explored the effects of high-intensity inspiratory muscle training in patients with heart disease on measures of cardiovascular function.

Aim: This study aims to investigate and interpret whether high-intensity inspiratory muscle training, beyond the usual care, improves endothelial function and arterial stiffness on cardiovascular function in patients with heart disease.

Methods: The study was designed as a randomized controlled trial. After coronary artery bypass graft surgery, patients will be invited to the study. The demographic and clinical characteristics of the patients will be recorded after consent is obtained from the volunteer patients who meet the inclusion criteria. Subsequently, patients will be randomly divided into two groups for inspiratory muscle training (IMT) with 60% maximum inspiratory pressure (MIP) or sham inspiratory muscle training (Sham-control), for 4 weeks. In both groups, before and after 4-week training, resting blood pressure (systolic/diastolic), resting heart rate, endothelial function, arterial stiffness, functional exercise capacity, the severity of dyspnea, and inspiratory muscle functions will be measured.

Study Type

Interventional

Enrollment (Actual)

11

Phase

  • 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

  • United States
    • Illinois
      • Chicago, Illinois, United States, 60608
        • University of Illinois at Chicago
      • Chicago, Illinois, United States, 60612
        • University of Illinois Chicago

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Aged >18 years old
  • Be able to walk independently.
  • Had coronary artery bypass graft (CABG) surgery, history of percutaneous coronary interventions, heart failure, and/or myocardial infarction.
  • Sufficient English language comprehension and cognitive ability to understand the study protocol, give informed consent and follow instructions.

Exclusion Criteria:

  • Being a current smoker (or tobacco).
  • Having a diagnosed chronic disease such as inflammatory bowel disease/irritable bowel syndrome, cerebrovascular diseases, COPD, chronic kidney disease requiring dialysis, neurological disorders, or diseases that may affect motor/cognitive function [multiple sclerosis, Parkinson's disease, polio, Alzheimer's disease, dementia, or other brain diseases of ageing])
  • Getting a score below 24 on the Standardized Mini Mental Test
  • Using antipsychotic medications commonly used to treat schizophrenia or schizoaffective disorders (i.e., haloperidol)
  • Having had any other previous cardiothoracic operation except CABG (e.g. Pneumonectomy, lobectomy, etc.)
  • Having a history of unstable-angina
  • Having had pneumonia in the last 3 months

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Study Group
Patients who will perform inspiratory muscle training (IMT) with %60 of MIP intensity
Device: IMT
The IMT protocol will consist of high-intensity daily training - 2 sets of 30 breaths with a 1-minute rest between sets, twice a day for 4 weeks using an IMT Threshold device (Threshold IMT Philips® Respironics, Inc). The intensity of the training will be set to 60% of each patient's maximal inspiratory pressure.
Sham Comparator: Sham Group
Patients who will perform Sham-IMT
Device: Sham-IMT
The sham IMT protocol will consist of high-intensity daily training - 2 sets of 30 breaths with a 1-minute rest between sets, twice a day for 4 weeks using an IMT Threshold device (Threshold IMT Philips® Respironics, Inc) without intensity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Inspiratory Muscle Function
Time Frame: 4 weeks
maximal inspiratory pressure (MIP) is the highest pressure measured during inspiration will be used.
4 weeks
Endothelial Function
Time Frame: 4 weeks
flow-mediated dilation (FMD) ultrasound measurements of brachial artery flow-mediated dilatation will be performed.
4 weeks
Arterial Stiffness
Time Frame: 4 weeks
arterial stiffness will be assessed by measuring pulse wave velocity.
4 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Functional Exercise Capacity
Time Frame: 4 weeks
maximal distance in 6 minute walk test will be used.
4 weeks
Dyspnea
Time Frame: 4 weeks
The modified Medical Research Council (mMRC) Dyspnea Scale, which have 5 points (0 to 4) will be used. High scores presented worsen dyspnea.
4 weeks

Collaborators and Investigators

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

Sponsor

University of Illinois at Chicago

Collaborators

The Scientific and Technological Research Council of Turkey

Investigators

  • Principal Investigator: Cemal Ozemek, Assoc. Prof., University of Illinois at Chicago

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 (Actual)

December 20, 2023

Primary Completion (Actual)

June 7, 2024

Study Completion (Actual)

June 15, 2024

Study Registration Dates

First Submitted

November 6, 2023

First Submitted That Met QC Criteria

November 6, 2023

First Posted (Actual)

November 13, 2023

Study Record Updates

Last Update Posted (Actual)

January 21, 2026

Last Update Submitted That Met QC Criteria

January 16, 2026

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY2023-1089

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

Yes

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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