Optimization of Interval Exercise Based-intensity on Ventilatory Anaerobic Threshold in Coronary Artery Disease

Influence of Interval Aerobic Exercise Training on Cardiorespiratory and Metabolic Variables and Inflammatory Markers in Patients With Different Level of Coronary Artery Lesions

The purpose of this study is to investigate the effects of interval training, based-intensity on 70% at 110% of oxygen consumption and workload attained on ventilatory anaerobic threshold, on aerobic functional capacity, autonomic modulation of heart rate, metabolic profile in patients with and without coronary artery disease.

Background: Exercise training has been essential component of the cardiac rehabilitation. However, it is not known if interval training based on ventilatory anaerobic threshold could be effective for improving aerobic functional capacity and metabolic profile.

Objective:To investigate the effects of interval training, based-intensity on 70% at 110% of oxygen consumption and workload attained on ventilatory anaerobic threshold, on aerobic functional capacity, autonomic modulation of heart rate, metabolic profile in patients with and without coronary artery disease.

Design: Prospective randomized controlled trial. Subjects: 68 men between 40 and 65 years old.

All subjects will be submitted:

1. - Clinical assessment: personal data, lifestyle and food, family history, current and previous history of disease.
2. - Physical examination: cardiac and lung auscultation,measurement of heart rate, blood pressure, body weight and height.
3. - Heart rate will be recorded at rest, in the supine position for 15 min, standing position for 10 min and respiratory sinus arrhythmia maneuver.
4. - Submaximal or symptom-limited cardiopulmonary exercise test on cycle ergometer will be performed to determined the ventilatory anaerobic threshold.
5. - Two cardiopulmonary exercise testing on treadmill at constant workload (moderate and high intensity). Expiratory flow limitation will be evaluated by flow-volume loops at the end of each exercise workload.
6. - Blood samples will be collected to analyze glycemic and lipid profiles.
7. - After these procedures, the subjects will be randomly assigned to one of two groups, trained group or control group.
8. - Interval training program will consist 30-40 minutes each exercise session, three times a week for 16 weeks, with a workload determined on the basis of ventilatory anaerobic threshold.
9. - At 48 hours after the last day of training, the subjects will repeat all experimental procedures as in baseline testing. Controls will be retested 16 weeks after the completion of baseline testing.
10. - All subjects will be instructed to maintain their habitual diet without a standardized caloric restriction.

Thus, it is expected that interval training will promote beneficial physiological adaptations in patients with and without coronary artery disease.

Inclusion Criteria:

• All patients will be undergone a medical investigation for coronary artery disease, by coronary angiography, at the Hemodynamics Center of local Hospital.
• After this procedure, the CAD+ group will include 34 patients, who will have clinical evidence significant stenosis (<50% of stenosis in one or more major coronary vessels), or previous coronary artery intervention (such as percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery).
• The CAD- group will be comprised 32 patients without stenosis in coronary vessels (angiographically documented) and without history of previous myocardial infarction (MI), PCI or CABG.
• All the patients will have three or more cardiovascular risk factors such as obesity (body mass index >30 kg/m2), smoking, sedentary lifestyle according to the International Physical Activity Questionnaire (IPAQ) version 6, hypertension, diabetes mellitus (type 2 - nonusers of insulin), and dyslipidemia.

Exclusion Criteria:

• The exclusion criteria consisted of MI <6 months, PCI and CABG <3 months
• Severe cardiac arrhythmias
• Chronic obstructive pulmonary disease
• Unstable angina
• Osteomuscular disorders
• Diabetes mellitus (users of insulin)
• Renal failure
• Sequelae associated with stroke.