Heart Failure
Conditions
Brief summary
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).
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.
Interventions
OTHERExercise training of High Intensity
High intensity
OTHERExercise training of Moderate Intensity
Moderate intensity
OTHERUntraining
Sedentary
Sponsors
University of Sao Paulo General Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
30 Years to 65 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in muscle sympathetic nerve activity (MSNA) | Baseline and 12 weeks | MSNA is being assessed by microneurography |
| Change muscle mechanoreceptor sensitivity | Baseline and 12 weeks | The mechanoreceptor sensitivity is being assessed via passive exercise to the leg |
| Change muscle metaboreceptor sensitivity | Baseline and 12 weeks | The metaboreceptor sensitivity is being assessed via dynamic exercise to the leg.The exercise intensity is 30% maximum voluntary contraction. |
| Change in chemoreceptor sensitivity | Baseline and 12 weeks | Hypoxia via 10% oxygen |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Peripheral vascular function | Baseline and 12 weeks | Brachial artery flow-mediated dilation is being used to assess the vascular function |
| Skeletal muscle function | Baseline and 12 weeks | The skeletal muscle function is being assessed in biopsy samples collected in lateral vasts of thigh with needle of biopsy. |
Countries
Brazil
Contacts
PRINCIPAL_INVESTIGATORCalors Negrao, PhD
aHeart Institute, University of São Paulo Medical School, São Paulo, Brazil
Outcome results
None listed