Impact of Interval Training on Sympathetic Hyperactivity and Vascular Function
Study Details
Study Description
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).
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
N/A |
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 Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| 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:
|
| 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
|
Outcome Measures
Primary Outcome Measures
- 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 Outcome Measures
- 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.
Eligibility Criteria
Criteria
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
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Heart Institute | São Paulo | Cerqueira Cesar | Brazil | |
| 2 | Heart Institute (InCor) | Sao Paulo | SP | Brazil | 05403-900 |
Sponsors and Collaborators
- University of Sao Paulo General Hospital
Investigators
- Principal Investigator: Calors Negrao, PhD, aHeart Institute, University of São Paulo Medical School, São Paulo, Brazil
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- SDC: 4070/14/050