Impact of Interval Training on Sympathetic Hyperactivity and Vascular Function

April 28, 2026 updated by: University of Sao Paulo General Hospital

The Impact of High-intensity Interval Training Versus Moderate Continuous Training on Neurovascular Control in Patients With Heart Failure

In this study, the investigators are testing the hypothesis that reduction in sympathetic activity would be greater following high-intensity interval training (HIIT) than moderate-intensity continuous training (MICT) and correspond with improvements in peripheral vascular function, and skeletal muscle function in patients with heart failure with reduced ejection fraction (HFrEF).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

In this study, the investigators are testing the hypothesis that reductions in sympathetic activity would be greater following high-intensity interval training (HIIT) than moderate-intensity continuous training (MICT) and correspond with improvements in peripheral vascular function, and skeletal muscle function in patients with heart failure with reduced ejection fraction (HFrEF). To test this hypothesis patients with chronic heart failure (30 - 65 years), left ventricular ejection fraction ≤40%, Functional Classes II-III), are being randomized into exercise with HIIT, MICT or no training (NT) three times/week for 12 weeks. Muscle sympathetic nerve activity is assessed by microneurography. Brachial artery flow-mediated dilation (FMD), blood flow and vascular conductance were assessed by ultrasonography. Blood pressure (BP) and heart rate (HR) by are being measured via finger photoplethysmograph and peak oxygen uptake (V̇O2peak) by a cardiopulmonary exercise test on ergometer cycle for leg. Biopsy samples from the lateral vast of the thigh are being collected for analysis of the intracellular mechanisms in the skeletal muscle. Exercise training is being conducted under supervision at the Heart Institute, School of Medicine, University of São Paulo. Both HIIT and MICT are performed on a cycle ergometer, three times per week for 12 weeks, and training sessions were matched for energy expenditure (i.e., an isocaloric energy expenditure of 200 Kcal/session). The intensity of the MICT session is established based on the HR and workload levels corresponding to anaerobic threshold and respiratory compensation point (RCP). The intensity of the HIIT session is established based on the HR and workload levels corresponding to 5% above the RCP. All exercise sessions were performed under the supervision of an exercise physiologist. The patients in the NT group were instructed to avoid any regular exercise program or any non-supervised exercise protocol during the study. All patients are being assessed before (pre) and after (post) both exercise training modes or control, no training.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
35

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

  • Brazil
    • Cerqueira Cesar
      • São Paulo, Cerqueira Cesar, Brazil
        • Heart Institute
    • São Paulo
      • São Paulo, São Paulo, Brazil, 05403-900
        • Heart Institute (InCor)

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

30 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Functional Class II to III of New York Heart Association
  • Left ventricular ejection fraction ≤40%
  • Peak oxygen uptake (V̇O2) <20 ml•kg-1•min-1

Exclusion Criteria:

  • Myocardial infarction within three months
  • Unstable angina
  • Acute heart failure
  • Pacemaker
  • Pulmonary disease
  • Chronic renal disease
  • Peripheral neuropathy
  • History of stroke
  • Untreated hypo/hyperthyroidism
  • Body mass index (BMI) >30 kg/m2
  • History of smoking

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: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: High-intensity interval training (HIIT)
High-intensity interval training (HIIT) = the exercise of high intensity perform on a cycle ergometer, three times per week for 12 weeks, and training sessions were matched for energy expenditure (i.e., an isocaloric energy expenditure of 200 Kcal/session). The intensity of the HIIT session was established based on the HR and workload levels corresponding to 5% above the respiratory compensation point.
Other: Exercise training of High Intensity
High intensity
Other Names:
  • Physical exercise
Experimental: Moderate-intensity continuous training (MICT)
Moderate-intensity continuous training (MICT) = the exercise of moderate intensity perform on a cycle ergometer, three times per week for 12 weeks, and training sessions were matched for energy expenditure (i.e., an isocaloric energy expenditure of 200 Kcal/session). The intensity of the MICT session was established based on the HR and workload levels corresponding to anaerobic threshold and respiratory compensation point
Other: Exercise training of Moderate Intensity
Moderate intensity
Sham Comparator: No training
The patients are instructed to avoid any regular exercise program or any non-supervised exercise protocol during the study.
Other: Untraining
Sedentary

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in muscle sympathetic nerve activity (MSNA)
Time Frame: Baseline and 12 weeks
MSNA is being assessed by microneurography
Baseline and 12 weeks
Change muscle mechanoreceptor sensitivity
Time Frame: Baseline and 12 weeks
The mechanoreceptor sensitivity is being assessed via passive exercise to the leg
Baseline and 12 weeks
Change muscle metaboreceptor sensitivity
Time Frame: Baseline and 12 weeks
The metaboreceptor sensitivity is being assessed via dynamic exercise to the leg.The exercise intensity is 30% maximum voluntary contraction.
Baseline and 12 weeks
Change in chemoreceptor sensitivity
Time Frame: Baseline and 12 weeks
Hypoxia via 10% oxygen
Baseline and 12 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Peripheral vascular function
Time Frame: Baseline and 12 weeks
Brachial artery flow-mediated dilation is being used to assess the vascular function
Baseline and 12 weeks
Skeletal muscle function
Time Frame: Baseline and 12 weeks
The skeletal muscle function is being assessed in biopsy samples collected in lateral vasts of thigh with needle of biopsy.
Baseline and 12 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Sao Paulo General Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Calors Negrao, PhD, aHeart Institute, University of São Paulo Medical School, São Paulo, Brazil

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 1, 2021

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 23, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 28, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 30, 2020

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2022

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SDC: 4070/14/050

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

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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