High-Intensity Interval Versus Aerobic Training for Patient-Reported Outcomes in Women With Heart Failure. (HIIT-WHEF)

Entrenamiento interválico de Alta Intensidad Versus Entrenamiento aeróbico Para Resultados Reportados Por Pacientes en Mujeres Con Insuficiencia cardíaca (HIIT-WHEF, High-intensity Interval Versus Aerobic Training for Patient-reported Outcomes in Women With Heart Failure): un Ensayo clínico Piloto, Prospectivo, Aleatorizado y de Factibilidad.

Heart failure is associated with impaired health-related quality of life and reduced exercise capacity. Women remain under-represented in cardiac rehabilitation research, and evidence comparing high-intensity interval training (HIIT) with moderate-intensity continuous training (MICT) in women with heart failure is limited.

HIIT-WHEF is a prospective, single-centre, randomised pilot feasibility trial involving 36 women aged 18 years or older with heart failure and a left ventricular ejection fraction below 50%. Participants will be randomly allocated in a 1:1 ratio to a 12-week supervised cardiac rehabilitation programme incorporating either HIIT or MICT. Both groups will also undertake individualised resistance training.

The primary objectives are to assess the feasibility and safety of conducting the randomised trial, including recruitment, acceptance, retention, adherence, intervention fidelity, completeness of outcome data and exercise-related adverse events. Health-related quality of life, assessed using the Minnesota Living with Heart Failure Questionnaire (MLHFQ), is the key clinical outcome of interest. Peak oxygen uptake, left ventricular ejection fraction and biomarkers will be assessed as exploratory clinical outcomes.

The study is designed to inform the planning of a future adequately powered confirmatory trial. It is not intended to establish definitive evidence of the superiority of HIIT over MICT.

Study Overview

• Status: Not yet recruiting
• Conditions: Heart Failure Reduced Ejection Fraction
• Intervention / Treatment: Behavioral: HIIT + Strength Training; Behavioral: MICT + Strength Training

Detailed Description

HIIT-WHEF will be conducted in the cardiac rehabilitation unit of Hospital Universitario Reina Sofía, Córdoba, Spain. Eligible women with clinically stable heart failure, New York Heart Association functional class I-II, a left ventricular ejection fraction below 50%, and stable, guideline-directed medical treatment will be considered for participation following referral for cardiac rehabilitation.

After baseline assessment and written informed consent, 36 participants will be randomly allocated to HIIT or MICT in a 1:1 ratio, with concealed allocation. Outcome assessors and data analysts will remain blinded to treatment allocation where feasible.

Both interventions will be delivered over 12 weeks, three supervised sessions per week. HIIT will comprise repeated high-intensity exercise intervals above the second ventilatory threshold, interspersed with active recovery below the first ventilatory threshold. MICT will comprise continuous aerobic exercise at an individually prescribed moderate intensity, between the first and second ventilatory thresholds. Both groups will receive resistance training, with exercise prescription and progression individualised according to functional capacity, symptoms and clinical response.

Feasibility outcomes will include recruitment rate, acceptance of randomisation, retention, adherence to prescribed sessions, fidelity to the assigned intervention, completeness of MLHFQ and other outcome assessments, and the frequency and nature of adverse events, particularly those related to exercise.

The MLHFQ will be assessed before and after the intervention. Peak oxygen uptake will be measured by cardiopulmonary exercise testing, left ventricular ejection fraction by echocardiography, and relevant blood biomarkers will be collected. Clinical outcomes will be analysed primarily using analysis of covariance, adjusting for baseline values, and reported with estimates and 95% confidence intervals. Given the pilot design and sample size, clinical comparisons will be exploratory and will inform the design of a future confirmatory trial.

Women who decline cardiac rehabilitation may be invited to participate in a separate observational registry, subject to separate informed consent. These women will not form part of the randomised comparison.

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Martín Ruiz Ortiz, MD, PhD; Phone Number: +34957010329; Email: martin.ruiz@ui1.es; maruor@gmail.com

Study Locations

• Spain
  • Córdoba
    • Córdoba, Córdoba, Spain, 14005
      • Hospital Universitario Reina Sofía.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

1. Women aged 18 years or older.
2. Documented diagnosis of heart failure with a left ventricular ejection fraction (LVEF) below 50%.
3. Stable symptoms corresponding to New York Heart Association functional class I-II.
4. Clinically stable and receiving stable, guideline-directed medical treatment at the maximum tolerated doses, as appropriate.
5. Referred by the responsible cardiologist for cardiac rehabilitation according to usual clinical practice.
6. No contraindication to supervised cardiac rehabilitation, cardiopulmonary exercise testing or the allocated exercise intervention.
7. Written informed consent provided before enrolment.

Exclusion Criteria:

1. Acute coronary syndrome or cardiac surgery within the previous 15 days.
2. Uncontrolled arrhythmias.
3. Severe valvular heart disease with an indication for intervention.
4. Musculoskeletal or neurological limitations that prevent the performance of exercise.
5. Any contraindication to cardiopulmonary exercise testing or high-intensity exercise training.
6. Clinical or haemodynamic instability, decompensated heart failure, unstable angina, clinically significant uncontrolled arrhythmias, or any other cardiovascular or non-cardiovascular condition that, in the judgement of the responsible clinical team, makes exercise unsafe at the time of assessment.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High-Intensity Interval Training (HIIT); Patients assigned to HIIT	Behavioral: HIIT + Strength Training; A 12-week supervised cardiac rehabilitation programme consisting of three individual sessions per week. Aerobic exercise will be performed on a treadmill or cycle ergometer, with intensity individually prescribed according to cardiopulmonary exercise testing and ventilatory thresholds. Sessions will include a 5-minute warm-up below the first ventilatory threshold, at least four high-intensity intervals above the second ventilatory threshold interspersed with active recovery intervals of equal duration below the first ventilatory threshold, and a 5-minute cool-down. Exercise duration and intensity will be progressed according to individual tolerance and clinical response. Both groups will also undertake individualised resistance training targeting the major muscle groups. Total session duration will be approximately 60 minutes. All sessions will be supervised by a physiotherapist, with clinical monitoring and exercise modification or interruption when indicated for safety.
Active Comparator: Moderate-Intensity Continuous Training (MICT); Patients assigned to MICT	Behavioral: MICT + Strength Training; A 12-week supervised cardiac rehabilitation programme consisting of three individual sessions per week. Aerobic exercise will be performed on a treadmill or cycle ergometer at an individually prescribed moderate intensity between the first and second ventilatory thresholds, avoiding significant dyspnoea. Sessions will include a 5-minute warm-up below the first ventilatory threshold and a 5-minute cool-down. Exercise duration will progress according to individual tolerance and clinical response, towards approximately 30 minutes of continuous aerobic exercise. Both groups will also undertake individualised resistance training targeting the major muscle groups, progressing towards approximately 40-60% of one-repetition maximum, with 8-15 repetitions and at least two sets per muscle group when tolerated. Total session duration will be approximately 60 minutes. All sessions will be supervised by a physiotherapist, with clinical monitoring and exercise modification or interruption when indic

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recruitment Rate	Number of participants randomised per month during the first nine months of recruitment. Feasibility will be classified as green if at least 2 participants per month are randomised, amber if 1 to less than 2 participants per month are randomised, and red if fewer than 1 participant per month is randomised.	From the start of recruitment to the end of the first 9 months of recruitment.
Acceptance of Randomisation	Proportion of eligible women referred for cardiac rehabilitation who agree to randomisation. Green: at least 50%; amber: 30% to less than 50%; red: less than 30%.	From screening and referral throughout the recruitment period.
Participant Retention	Proportion of randomised participants with a post-intervention assessment. Green: at least 85%; amber: 70% to less than 85%; red: less than 70%.	At the end of the 12-week intervention.
Adherence to Prescribed Exercise Sessions	Proportion of prescribed exercise sessions attended by participants who complete the programme. Green: at least 80%; amber: 65% to less than 80%; red: less than 65%.	Throughout the 12-week intervention.
Fidelity to the Assigned HIIT Intervention	Proportion of HIIT sessions in which at least four intervals are completed above the second ventilatory threshold. Green: at least 75%; amber: 60% to less than 75%; red: less than 60%.	Throughout the 12-week intervention.
Completeness of Post-Intervention MLHFQ Data	Proportion of randomised participants with a completed Minnesota Living with Heart Failure Questionnaire (MLHFQ) at post-intervention assessment. Green: at least 90%; amber: 75% to less than 90%; red: less than 75%.	At the end of the 12-week intervention.
Exercise-Related Adverse Events	Frequency and nature of adverse events related to exercise, including serious adverse events and events requiring modification of exercise prescription. Feasibility criteria are green if no serious exercise-related adverse event occurs; amber if non-serious events require modification of the prescription in more than 20% of cases; and red if any serious adverse event attributable to exercise occurs.	Throughout the 12-week intervention and the study period in which exercise-related adverse events are monitored.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Minnesota Living with Heart Failure Questionnaire (MLHFQ) Total Score	Between-group difference in the post-intervention MLHFQ total score, adjusted for baseline score using analysis of covariance (ANCOVA). The MLHFQ ranges from 0 to 105, with higher scores indicating worse health-related quality of life. The baseline-to-post-intervention change will also be reported. This is an exploratory clinical outcome in the pilot trial and will not be used to establish confirmatory superiority.	Baseline and 12 weeks.
Change in Peak Oxygen Consumption (VO2peak)	Between-group difference in peak oxygen uptake measured during cardiopulmonary exercise testing, adjusted for baseline VO2peak. VO2peak will be expressed in mL/kg/min and defined as the highest oxygen uptake achieved during the final 30 seconds of exercise.	Baseline and at 12 weeks
Change in Left Ventricular Ejection Fraction (LVEF)	Between-group difference in left ventricular ejection fraction measured by echocardiography, adjusted for baseline LVEF. Results will be expressed as percentage points.	Baseline and at 12 weeks
Changes in NT-proBNP, High-Sensitivity C-Reactive Protein and CA125	Changes in circulating NT-proBNP, high-sensitivity C-reactive protein (hs-CRP) and CA125 concentrations from baseline to post-intervention. Between-group comparisons will be exploratory and adjusted for baseline values where appropriate.	Baseline and at 12 weeks

Collaborators and Investigators

• Sponsor: Universidad Internacional Isabel I de Castilla
• Collaborators: Hospital Universitario Reina Sofia de Cordoba
• Investigators: Principal Investigator: Martín Ruiz Ortiz, MD, PhD, Hospital Universitario Reina Sofía. Córdoba. Universidad Internacional Isabel I. Burgos. Spain

Study record dates

Study Major Dates

• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: November 3, 2026
• First Submitted That Met QC Criteria: November 3, 2026
• First Posted (Actual): November 9, 2026

Study Record Updates

• Last Update Posted (Actual): November 9, 2026
• Last Update Submitted That Met QC Criteria: November 3, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Quality of Life; Women; Women's Health; Cardiac Rehabilitation; Exercise Therapy; High-Intensity Interval Training (HIIT); Patient-Reported Outcome Measures; Heart Failure Reduced Ejection Fraction; Moderate-Intensity Continuous Training (MICT)
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases; Heart Failure; Heart Failure, Systolic; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Therapeutics; Physical Therapy Modalities; Patient Care; Exercise Therapy; Rehabilitation; Aftercare; Continuity of Patient Care; Physical Conditioning, Human; Exercise; Resistance Training
• Other Study ID Numbers: HIIT-WHEF V4.0

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

De-identified individual participant data (IPD) that underlie the results reported in future publications (including text, tables, and figures) will be made available to qualified researchers for scientifically sound research proposals. Data sharing will be conducted in strict compliance with the European General Data Protection Regulation (GDPR) and Spanish Organic Law 3/2018. Requests must be evaluated and approved by the competent Research Ethics Committee.

IPD Sharing Time Frame

Available beginning 6 months and ending 5 years following article publication.

IPD Sharing Access Criteria

Data requests should be sent via email to the Principal Investigator (maruor@gmail.com) and the Data Protection Officers (dpo@ui1.es / dpd@imibic.org). Requesters must provide a methodologically sound proposal and obtain prior approval from an authorized Research Ethics Committee. Data will be shared via a secure, encrypted file transfer.

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No