Impact of Interval Training on Sympathetic Hyperactivity and Vascular Function

University of Sao Paulo General Hospital

Status: Unknown

Conditions: Heart Failure

Treatments: Other: Untraining; Other: Exercise training of High Intensity; Other: Exercise training of Moderate Intensity

Study type: Interventional

Funder types: Other

Identifiers

NCT04248894

SDC: 4070/14/050

Details and patient eligibility

About

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).

Full 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.

Enrollment: 35 estimated patients

Sex: All

Ages: 30 to 65 years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Other

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

---

35 participants in 3 patient groups

High-intensity interval training (HIIT)

Experimental group

Description:

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.

Treatment:

Other: Exercise training of High Intensity

Moderate-intensity continuous training (MICT)

Experimental group

Description:

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

Treatment:

Other: Exercise training of Moderate Intensity

No training

Sham Comparator group

Description:

The patients are instructed to avoid any regular exercise program or any non-supervised exercise protocol during the study.

Treatment:

Other: Untraining