Impact of Interval Training on Sympathetic Hyperactivity and Vascular Function
- Conditions
- Heart Failure
- Interventions
- Other: Exercise training of Moderate IntensityOther: Exercise training of High IntensityOther: Untraining
- Registration Number
- NCT04248894
- Lead Sponsor
- University of Sao Paulo General Hospital
- 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.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- All
- Target Recruitment
- 35
- 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
- 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 & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Moderate-intensity continuous training (MICT) Exercise training of Moderate Intensity 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 High-intensity interval training (HIIT) Exercise training of High Intensity 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. No training Untraining The patients are instructed to avoid any regular exercise program or any non-supervised exercise protocol during the study.
- Primary Outcome Measures
Name Time Method Change muscle mechanoreceptor sensitivity Baseline and 12 weeks The mechanoreceptor sensitivity is being assessed via passive exercise to the leg
Change in muscle sympathetic nerve activity (MSNA) Baseline and 12 weeks MSNA is being assessed by microneurography
Change in chemoreceptor sensitivity Baseline and 12 weeks Hypoxia via 10% oxygen
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.
- Secondary Outcome Measures
Name Time Method 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.
Trial Locations
- Locations (2)
Heart Institute (InCor)
🇧🇷Sao Paulo, SP, Brazil
Heart Institute
🇧🇷São Paulo, Cerqueira Cesar, Brazil