Inspiratory Muscle Training for People With Heart Failure

NCT07672041 | Not Yet Recruiting

• 2 other identifiers: 033/202611261229
• Study Type: interventional
• Target: 108
• Locations: 1 country
• Sites: 1

Brief Summary

Heart failure is frequently associated with inspiratory muscle weakness, which contributes to dyspnea, reduced exercise capacity, impaired quality of life, and adverse cardiovascular outcomes. Although inspiratory muscle training (IMT) is a recommended adjunct to cardiovascular rehabilitation, the optimal training modality remains uncertain, particularly among patients with reduced and preserved ejection fraction. This randomized controlled trial will evaluate the efficacy of a novel inspiratory muscle training protocol using tapered flow resistive loading (TFRL) compared with conventional threshold loading (TL) and usual care. A total of 108 clinically stable patients with heart failure (NYHA class II-III) will be enrolled. Participants will be stratified according to heart failure phenotype (reduced or preserved ejection fraction) and allocated to one of three groups: TFRL, TL, or control. Both training interventions will be performed for 8 weeks in combination with supervised exercise-based cardiac rehabilitation. Primary and secondary outcomes will include inspiratory muscle strength and endurance, exercise capacity, pulmonary function, dyspnea, skeletal muscle oxygenation, autonomic balance, arterial stiffness, and health-related quality of life. The study is powered to detect moderate between-group differences and interaction effects with 80% statistical power and a two-sided alpha level of 0.05. Changes over time and between groups will be analyzed using analysis of covariance (ANCOVA), adjusting for baseline inspiratory muscle strength. The trial aims to determine whether TFRL provides superior clinical and physiological benefits compared with conventional inspiratory muscle training and whether treatment responses differ according to heart failure phenotype.

Conditions

Heart Failure

Keywords

Heart Failure; Inspiratory Muscle Training; Cardiac Rehabilitation; Tapered Flow Resistive Loading; Exercise Capacity

Outcome Measures

Primary Outcomes (3)

• Exercise capacity

  Improve cardiorespiratory capacity assessed peak oxygen uptake (VO2peak)

  From enrollment to the end of treatment at 8 weeks

• Maximal inspiratory muscle strength

  Improve maximal inspiratory pressure which implies an increase in the values measured in millimeters of mercury (mmHg).

  From enrollment to the end of treatment at 8 weeks

• Arterial stiffness

  Decrease in pulse wave velocity measured using a Holter blood pressure monitor.

  From enrollment to the end of treatment at 8 weeks

Secondary Outcomes (1)

• Health related quality of life

  From enrollment to the end of treatment at 8 weeks

Study Arms (3)

Tapered flow resistive load (TFRL)

EXPERIMENTAL

This group will perform an inspiratory muscle training using a flow resistive loading device (POWER Breathe KH2) and they will be instructed to perform each inspiratory effort from functional residual capacity

Other: Inspiratory muscle training with Tapered Resistive Load; Other: Concurrent Exercise Training

Threshold load (TL)

EXPERIMENTAL

This group will perform inspiratory muscle training using a pressure threshold loading device (POWER Breathe Plus Medic) and they will be instructed to perform each inspiratory effort from functional residual capacity

Other: Inspiratory muscle training with threshold load; Other: Concurrent Exercise Training

Control Group (CG)

ACTIVE COMPARATOR

This group will receive a Usual Care program, i.e., only cardiac rehabilitation with whole exercise

Other: Concurrent Exercise Training

Interventions

Inspiratory muscle training with Tapered Resistive Load OTHER

The resistance pressure of the Tapered Resistive Load Device (POWER Breathe KH2) will be set at 60% of each participant's maximum inspiratory pressure measured at baseline. Re-evaluations of peak inspiratory pressure in both exercise groups will be carried out every 2 weeks to perform load progression. The training protocol has 6 levels depending on the rest period. The first level has 60 second rest periods and from the second level through the sixth level, the rest period will be reduced to 45, 30, 15, 10, and 5 seconds. All participants in all groups will perform 6 inspiratory efforts at each level. In total, each participant will perform 36 inspiratory efforts (6 levels x 6 efforts = 36 total efforts). Training sessions will be supervised and performed three times a week for 8 weeks.

Tapered flow resistive load (TFRL)

Inspiratory muscle training with threshold load OTHER

The resistance pressure of the threshold device (POWER Breathe Plus Medic) will be set at 60% of each participant's maximum inspiratory pressure measured at baseline. Re-evaluations of peak inspiratory pressure in both exercise groups will be carried out every 2 weeks to perform load progression. The training protocol has 6 levels depending on the rest period. The first level has 60 second rest periods and from the second level through the sixth level, the rest period will be reduced to 45, 30, 15, 10, and 5 seconds. All participants in all groups will perform 6 inspiratory efforts at each level. In total, each participant will perform 36 inspiratory efforts (6 levels x 6 efforts = 36 total efforts). Training sessions will be supervised and performed three times a week for 8 weeks.

Threshold load (TL)

Concurrent Exercise Training OTHER

The concurrent training program will include aerobic and resistance exercise. Aerobic training will begin after a 5-minute warm-up at low to moderate intensity. This will be followed by 40 minutes of aerobic exercise at the anaerobic threshold (AT) power (PO) obtained from a cardiopulmonary exercise test. Each session will include 8 intervals of 3 minutes (110-120% of AT-PO) and 8 intervals of 2 minutes of active recovery (70-80% of AT-PO). Training intensity increased by 10% each week while maintaining a Borg scale rating of 13-14, provided that no abnormal cardiovascular or electrocardiographic signs or symptoms were observed. Resistance training will be conducted in 10-minute sessions with at least 6 different exercises using between 40% and 50% of one-repetition maximum (1RM). The 1RM will be calculated using Brzycki's submaximal repetition formula (Weight/(1.0278 - (0.0278\*Reps)). Subsequently, 5 minutes of stretching will be performed as a cool-down.

Control Group (CG); Tapered flow resistive load (TFRL); Threshold load (TL)

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• History of symptomatic heart failure (NYHA functional class I and III).
• Participants able to understand and respond to the instructions given in the study
• Unaltered dose and type of medication up to three months before the start of the study

You may not qualify if:

• Participants unable to perform a valid baseline cardiopulmonary exercise test.
• Participants with unstable angina, acute myocardial infarction, and/or heart surgery within the past three months.
• Participants with other concomitant cardiac or neurological disease.
• Participants with difficulties in maintaining a proper mouth seal or unable to avoid air leakage during pulmonary function testing.
• Participants in other non-pharmacological study will be also excluded.
• Current smokers.
• Cardiac acute decompensation.

Sponsors & Collaborators

• Universidad Nacional Andres Bello: lead

Study Sites (1)

Centro de Salud Sports Medicina Deportiva

Viña del Mar, Valparaiso, 2372067, Chile

Location

Related Publications (4)

• Palau P, Dominguez E, Nunez E, Schmid JP, Vergara P, Ramon JM, Mascarell B, Sanchis J, Chorro FJ, Nunez J. Effects of inspiratory muscle training in patients with heart failure with preserved ejection fraction. Eur J Prev Cardiol. 2014 Dec;21(12):1465-73. doi: 10.1177/2047487313498832. Epub 2013 Jul 17.

  PMID: 23864363 BACKGROUND

• Bosnak-Guclu M, Arikan H, Savci S, Inal-Ince D, Tulumen E, Aytemir K, Tokgozoglu L. Effects of inspiratory muscle training in patients with heart failure. Respir Med. 2011 Nov;105(11):1671-81. doi: 10.1016/j.rmed.2011.05.001. Epub 2011 May 31.

  PMID: 21621993 BACKGROUND

• Ahmad AM, Hassan MH. Effects of Addition of Inspiratory Muscle Training to Exercise-Based Cardiac Rehabilitation on Inspiratory Muscle Strength, Peak Oxygen Consumption, and Selected Hemodynamics in Chronic Heart Failure. Acta Cardiol Sin. 2022 Jul;38(4):485-494. doi: 10.6515/ACS.202207_38(4).20220117A.

  PMID: 35873122 BACKGROUND

• Siddiqi AK, Shahzad M, Kumar A, Ahmed M, Sridharan L, Abdou MH, Naeem M. The efficacy of inspiratory muscle training in improving clinical outcomes in heart failure patients: An updated systematic review and meta-analysis. J Cardiol. 2025 May;85(5):374-385. doi: 10.1016/j.jjcc.2025.01.016. Epub 2025 Feb 3.

  PMID: 39909304 BACKGROUND

MeSH Terms

Conditions

Heart Failure

Condition Hierarchy (Ancestors)

Heart Diseases; Cardiovascular Diseases

Central Study Contacts

Marcelo R Tuesta, Doctor of Philosophy

CONTACT

+56973892114; marcelo.tuesta@unab.cl

Alvaro R Reyes, Doctor of Philosophy

CONTACT

+56994339083; alvaro.reyes@unab.cl

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Doctor of Philosophy degree

Study Record Dates

• First Submitted: June 22, 2026
• First Posted: June 26, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): July 1, 2028
• Last Updated: June 26, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

CL (1)