Acute Hemodynamic Responses to Blood Flow Restriction Aerobic Exercise in Interstitial Lung Disease

January 31, 2026 updated by: Meral Boşnak Güçlü, Gazi University

Investigation of the Acute Effects of Blood Flow Restriction Aerobic Exercise on Hemodynamic Responses and Muscle Oxygen in Patients With Interstitial Lung Disease

Interstitial lung diseases (ILD)impaired gas exchange and reduced lung elasticity lead to marked reductions in exercise capacity and decreased oxygen consumption due to circulatory limitations. Blood flow restriction (BFR) exercise involves applying external pressure to partially restrict venous return without entirely blocking arterial inflow. This controlled compression induces temporary hypoxic and metabolic stress, triggering high-intensity-like responses that stimulate growth hormone release, increase protein synthesis, and promote muscle hypertrophy. However, the most crucial advantage of blood flow restriction during exercise is its ability to increase muscle mass during aerobic training. IIn individuals with ILD, BFR may offer a safe and practical way to improve muscle mass and exercise capacity with minimal additional strain on the cardiovascular and musculoskeletal systems.Our study aimed to compare the acute effects of low-intensity blood flow restriction aerobic exercise training and low-intensity aerobic exercise training on hemodynamic responses and muscle oxygenation in patients with ILD. Method: 30 patients with a diagnosis of ILD being followed up will be included in the study. Our study was a randomized, crossover, triple-blind, prospective study. Assessments will be performed at the beginning of the study. On the first day, demographic data and clinical findings of the individuals will be collected. Patients will be asked questions, and their responses will be recorded in their medical records. Respiratory function, respiratory muscle strength and endurance, and peripheral muscle strength will be evaluated. 48 hours from the first day, patients' maximal exercise capacity will be assessed with a cardiopulmonary exercise test (CPET), and muscle oxygenation during CPET will be assessed with a Moxy® monitor. Respiratory muscle fatigue will be assessed with an oral pressure monitor before and after the exercise test. The assessments will be completed over two days. One week after the evaluations, patients will be randomly assigned to two groups. One group will receive low-intensity aerobic exercise training, and the other will receive low-intensity aerobic exercise training with blood flow restriction. Muscle oxygenation will be assessed during both exercise sessions, and respiratory muscle fatigue will be measured before and after each session. All participants will receive both exercise sessions.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Interstitial lung diseases (ILD) constitute a group of disorders that diffusely affect the lungs, causing varying degrees of inflammation, fibrosis, and structural alterations in the lung parenchyma. These diseases may present with either acute or chronic progression and can involve not only the interstitium but also the alveoli, small airways, vascular structures, and pleura. The etiology of ILD is diverse and may be related to identifiable causes such as environmental or occupational exposures, medications, and radiation. Connective tissue diseases-including rheumatoid arthritis, systemic sclerosis, and systemic lupus erythematosus-along with several systemic disorders, may also lead to pulmonary damage and involvement. Systemic diseases can affect the lungs through infections, vasculitis, or inflammatory mechanisms. Globally, approximately two million individuals are affected by ILD, and in Türkiye, the incidence has been reported as 25.8 per 100,000. The most frequently encountered ILD subtypes include sarcoidosis, idiopathic pulmonary fibrosis, and hypersensitivity pneumonitis .

Dyspnea is one of the most common and disabling symptoms in individuals with ILD, substantially reducing quality of life. Respiratory irregularities observed at rest become more pronounced during exercise. Chronic cough is another prevalent symptom in ILD that negatively impacts daily functioning, social interactions, and psychological well-being, and may also indicate disease progression. Impaired gas exchange and reduced lung elasticity lead to a significant decrease in exercise capacity in ILD, resulting in limitations in daily activities. Assessment of exercise capacity is essential for monitoring disease severity and evaluating treatment effectiveness.

In individuals with ILD, progressive circulatory limitations reduce oxygen consumption. Fibrotic changes in the pulmonary vascular bed restrict blood flow, compromising oxygen delivery during exertion and leading to a marked reduction in VO₂ capacity. Pulmonary hypertension and decreased cardiac output further exacerbate this mechanism. During exercise, the oxygen pulse shows limited increase and may plateau or even decrease in some patients. Consequently, heart rate rises disproportionately compared with healthy individuals, increasing peripheral hypoxia and exercise-induced desaturation. Monitoring muscle oxygenation is important for determining how exercise interventions can be optimized to reduce dyspnea and improve exercise capacity.

Blood flow restriction (BFR) exercise was first introduced in 1966; however, it gained more attention in the mid-1980s due to its potential to induce strength gains at low exercise intensities, thereby reducing orthopedic injury risk. The technique relies on applying controlled external pressure to restrict venous return without completely occluding arterial inflow. This results in a temporary hypoxic and metabolically stressful environment distal to the cuff. Accumulation of lactic acid within the ischemic and hypoxic muscle environment leads to a decrease in intramuscular pH. These metabolic stress responses, which are typically observed during high-intensity exercise, stimulate growth hormone release. Growth hormone-mediated IGF-1 secretion enhances protein synthesis within muscle cells, ultimately promoting muscle hypertrophy. A key advantage of restricting blood flow during aerobic exercise is the potential to increase muscle mass even during low-intensity training .

In recent years, the applicability of BFR exercise has been demonstrated across various populations, including older adults, individuals with obesity, and those with cardiovascular conditions. However, most studies have been conducted in athletes and healthy individuals, and research in clinical populations remains limited. For individuals with ILD, BFR training may offer a safe and practical method to enhance both muscle mass and exercise capacity while imposing minimal stress on the cardiovascular and musculoskeletal systems.

Study Type

Interventional

Enrollment (Estimated)

30

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 Contact

Study Contact Backup

Study Locations

  • Turkey (Türkiye)
    • Çankaya
      • Ankara, Çankaya, Turkey (Türkiye), 06490
        • Gazi University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Cardiopulmonary Rehabilitation Unit
        • Contact:
        • 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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of interstitial lung disease according to the European Respiratory Society (ERS) and American Thoracic Society (ATS) diagnostic criteria.
  • Willingness to participate in the study and provide written informed consent.

Exclusion Criteria:

  • Presence of any acute infection at the time of the study.
  • Orthopedic or neurological conditions that may affect exercise capacity.
  • Contraindications to exercise testing according to the American College of Sports Medicine (ACSM) guidelines.
  • History of COVID-19 infection within the last three months.
  • Receiving treatments outside standard medical therapy.
  • Presence of peripheral arterial disease.
  • Presence of peripheral neuropathy.
  • Resting blood pressure greater than 160/100 mmHg.
  • History of deep vein thrombosis, pulmonary embolism, or stroke.

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: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Low-intensity Aerobic Exercise Training Group
Participants will perform the treadmill protocol (5-minute warm-up, 20-minute loading, 5-minute cool-down; intensity 30-39% HRR or 30-39% peak VO₂).
Other: Low-intensity aerobic exercise training
Participants will perform a single supervised aerobic exercise session on a treadmill under physiotherapist supervision. Exercise intensity will be set at 30-39% of heart rate reserve (HRR) or 30-39% of peak VO₂. The protocol will consist of 5 minutes of warm-up, 20 minutes of training at target intensity, and 5 minutes of cool-down (total duration: 30 minutes).
Experimental: Blood Flow Restriction (BFR) Low-Intensity Aerobic Exercise Group
Participants will perform the treadmill protocol (5-minute warm-up, 20-minute loading, 5-minute cool-down; intensity 30-39% HRR or 30-39% peak VO₂) with the addition of blood flow restriction.
Other: Blood flow restriction (BFR) low-intensity aerobic exercise training
Participants will perform a treadmill-based aerobic exercise session at 30-39% of heart rate reserve (HRR) or 30-39% of peak VO₂. The session will consist of 5 minutes of warm-up, 20 minutes of training at target intensity, and 5 minutes of cool-down (total duration: 30 minutes). Before the loading phase begins, a pneumatic external compression device will be placed around both thighs. Blood flow restriction will be applied only during the 20-minute loading phase and will not be used during warm-up or cool-down.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hemodynamic Responses
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
The primary outcome of the study will be the acute hemodynamic responses to low-intensity aerobic exercise with and without blood flow restriction in individuals with interstitial lung disease. Heart rate, respiratory rate, systolic and diastolic blood pressure, and peripheral oxygen saturation will be recorded. Maximum heart rate, perceived dyspnea, and fatigue levels reached during the exercise workload will also be documented. Hemodynamic responses will be assessed during two exercise sessions (Session 1 and Session 2), which are separated by a 7-day washout period. Measurements will be obtained before exercise (pre-exercise), during exercise, immediately after exercise, and at the first minute of recovery.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Heart Rate)
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Heart rate will be measured in beats per minute using a heart rate monitor before exercise, immediately after exercise, and at the first minute of recovery.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Systolic Blood Pressure)
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Systolic blood pressure will be measured in mmHg using a sphygmomanometer before exercise, immediately after exercise, and at the first minute of recovery.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Diastolic Blood Pressure)
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Diastolic blood pressure will be measured in mmHg using a sphygmomanometer before exercise, immediately post-exercise, and at the first minute of recovery.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Peripheral Oxygen Saturation (SpO₂))
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Oxygen saturation will be recorded using a portable pulse oximeter (SpO₂, %) at baseline, immediately after exercise, and during the first minute of recovery.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Respiratory Rate)
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Respiratory rate (breaths per minute) will be counted manually or with a monitor before exercise, immediately post-exercise, and at the first minute of recovery.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Dyspnea)
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Subjective perception of breathlessness will be assessed using the Modified Borg Scale (0-10) before exercise, at peak exercise, immediately after exercise, and at the first minute of recovery. Modified Borg Scale: The lowest 0 points "not at all" the highest 10 points "very severe" means shortness of breath.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Fatigue (Whole-body and Leg))
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Perceived overall fatigue and leg fatigue will be assessed using the Modified Borg Scale (0-10) at the same time points as dyspnea. Modified Borg Scale: The Modified Borg scale is a subjective scale that scores 0-10 for breathlessness and fatigue at rest and/or during activity. The lowest 0 points "not at all" the highest 10 points "very severe" means.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Hemodynamic Responses (Maximum Heart Rate)
Time Frame: During the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
The highest heart rate reached during the exercise session will be documented.
During the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Muscle Oxygenation
Time Frame: Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Muscle oxygenation will be evaluated using the Moxy® muscle oxygen monitor during both cardiopulmonary exercise testing and exercise training sessions. Local muscle oxygen saturation (SmO₂) and total hemoglobin (THb) values will be recorded at rest, immediately after exercise, and at the first minute of recovery.
Pre-exercise and during the exercise test on Day 1, and pre-exercise and during the first and second exercise sessions on Days 2 and 3.
Maximal Exercise Capacity
Time Frame: Baseline (Day 1)
Maximal exercise capacity will be evaluated with cardiopulmonary exercise testing (CPET). Breath-by-breath parameters including VO₂ (oxygen consumption, ml/min), VO₂/kg (oxygen consumption per kilogram per minute, ml/min/kg), METs (metabolic equivalents), V̇E (minute ventilation, L/min), V̇CO₂ (carbon dioxide production, ml/min), EqO₂ (ventilatory equivalent for oxygen), EqCO₂ (ventilatory equivalent for carbon dioxide), RER (respiratory exchange ratio), HR (heart rate, beats/min), HRR (heart rate reserve), VO₂/HR (oxygen pulse, ml), RR (respiratory rate, breaths/min), and SpO₂ (oxygen saturation, %) treadmill speed and gradient, and oxygen saturation will be continuously monitored.
Baseline (Day 1)
Respiratory Muscle Strength
Time Frame: Baseline (Day 1), Days 2 and 3
Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) will be measured using a portable mouth pressure device in accordance with American Thoracic Society and European Respiratory Society guidelines.Respiratory muscle fatigue assessments will be performed before and after exercise testing and repeated before and after each exercise intervention. Baseline assessments represent pre-exercise measurements. Day 2 and Day 3 correspond to the first and second exercise sessions, respectively.
Baseline (Day 1), Days 2 and 3
Respiratory Muscle Endurance
Time Frame: Baseline (Day 1)
Respiratory muscle endurance will be assessed using incremental threshold loading with a Powerbreathe® device.
Baseline (Day 1)
Peripheral Muscle Strength
Time Frame: Baseline (Day 1), Days 2 and 3
Quadriceps and shoulder abductor strength will be assessed using a handheld dynamometer. Three measurements will be taken, and the highest value will be recorded. Baseline assessments represent pre-exercise measurements. Day 2 and Day 3 correspond to the first and second exercise sessions, respectively.
Baseline (Day 1), Days 2 and 3
Pulmonary function (Forced vital capacity (FVC))
Time Frame: Baseline (Day 1)
Pulmonary function will be evaluated with the spirometry. Dynamic lung volume measurements will be made according to American Thoracic Society (ATS) and European Respiratory Society (ERS) criteria. With the device, forced vital capacity (FVC) will be evaluated.
Baseline (Day 1)
Pulmonary function (Forced expiratory volume in the first second (FEV1))
Time Frame: Baseline (Day 1)
Pulmonary function will be evaluated with the spirometry. Dynamic lung volume measurements will be made according to ATS and ERS criteria. With the device, forced expiratory volume in the first second (FEV1) will be evaluated.
Baseline (Day 1)
Pulmonary function (FEV1 / FVC)
Time Frame: Baseline (Day 1)
Pulmonary function will be evaluated with the spirometry. Dynamic lung volume measurements will be made according to ATS and ERS criteria. With the device, FEV1 / FVC will be evaluated.
Baseline (Day 1)
Pulmonary function (Flow rate 25-75% of forced expiratory volume (FEF 25-75%))
Time Frame: Baseline (Day 1)
Pulmonary function will be evaluated with the spirometry. Dynamic lung volume measurements will be made according to ATS and ERS criteria. With the device, flow rate 25-75% of forced expiratory volume (FEF 25-75%) will be evaluated.
Baseline (Day 1)
Pulmonary function (Peak flow rate (PEF))
Time Frame: Baseline (Day 1)
Pulmonary function will be evaluated with the spirometry. Dynamic lung volume measurements will be made according to ATS and ERS criteria. With the device, peak flow rate (PEF) will be evaluated.
Baseline (Day 1)

Collaborators and Investigators

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

Sponsor

Gazi University

Investigators

  • Study Director: Meral BOŞNAK GÜÇLÜ, Prof. Dr., Gazi University
  • Study Chair: Şeyma Mutlu Kayaarslan, PT, MSc, Başkent University and Gazi University
  • Principal Investigator: Betül Yoleri, PT, MSc, Gazi University
  • Principal Investigator: Nilgün Yılmaz Demirci, Prof. Dr., Gazi University Faculty of Medicine

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)

February 1, 2026

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

December 1, 2028

Study Registration Dates

First Submitted

November 26, 2025

First Submitted That Met QC Criteria

December 23, 2025

First Posted (Actual)

January 2, 2026

Study Record Updates

Last Update Posted (Actual)

February 3, 2026

Last Update Submitted That Met QC Criteria

January 31, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2025 - 1878

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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