Effects of Long Extensive Aerobic Interval Training Versus Long Extensive Continuous Training on Heart Rate-Power Decoupling in Patients With Ischemic Heart Disease: A Randomized Clinical Trial
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 48
- 主要终点
- Change in heart rate-power slope during a submaximal incremental cycling test
研究概览
简要总结
This study is a randomized, parallel-group clinical trial with assessor and statistical analyst blinding, conducted at a single center. Participants with stable ischemic heart disease enrolled in a cardiac rehabilitation program will be randomly allocated to one of two aerobic exercise interventions: long extensive continuous aerobic training (zone 2) or long extensive aerobic interval training (zone 3). Both groups will participate in supervised exercise sessions twice weekly for a period of 8 weeks, integrated into the standard cardiac rehabilitation program.
Assessments will be performed at baseline, immediately after the intervention period (8 weeks), and after a 4-week follow-up period without supervised training to evaluate potential detraining effects. The primary outcome is heart rate-power decoupling during a prolonged submaximal cycling exercise test, used as an indicator of cardiovascular efficiency. Secondary outcomes include heart rate response during submaximal exercise, exercise tolerance, heart rate recovery, blood pressure, functional capacity, quality of life, and adherence to the training program.
The objective of this study is to compare the effects of long extensive aerobic interval training versus long extensive continuous training on heart rate-power decoupling and related cardiovascular and functional outcomes in patients with ischemic heart disease undergoing cardiac rehabilitation.
详细描述
BACKGROUND AND RATIONALE Cardiac rehabilitation (CR) based on supervised aerobic exercise is a well-established intervention that reduces cardiovascular morbidity and mortality, improves functional capacity, and enhances quality of life in patients with ischemic heart disease. Two aerobic training modalities are routinely used within CR programs and recommended by international guidelines: moderate-intensity continuous training (MICT, zone 2), characterized by prolonged steady-state exercise below the first ventilatory threshold (65-75% HRmax); and long extensive interval training (LEIT, zone 3), which alternates prolonged work intervals between the two ventilatory thresholds (75-85% HRmax) with active recovery periods. Both modalities are standard components of the Phase II CR program at Hospital Universitario 12 de Octubre (HU12O), Madrid, where this trial is conducted.
Despite the established benefits of both training modalities, no randomized controlled trial has directly compared their effects on heart rate-power decoupling during submaximal exercise - a physiological marker of cardiovascular efficiency that remains underexplored in the CR setting.
HEART RATE-POWER DECOUPLING: PHYSIOLOGICAL BASIS During constant-load cycling exercise, an efficient cardiovascular system maintains a relatively stable heart rate (HR) over time. When HR progressively increases despite unchanged mechanical power output, this phenomenon - termed HR-power decoupling or cardiovascular drift - reflects a declining stroke volume compensated by chronotropic response, resulting in greater cardiac work per unit of mechanical output. A higher decoupling index indicates lower cardiorespiratory efficiency during submaximal exercise.
HR-power decoupling can be assessed using standard CR equipment (calibrated cycle ergometer and validated chest-strap HR monitor), without maximal testing or specialized technology, making it a clinically applicable and safe measure in this population. Reducing HR-power decoupling after training would indicate that the heart operates with lower hemodynamic load for the same mechanical demand - a meaningful adaptation in terms of myocardial oxygen consumption, exercise tolerance, and long-term cardiovascular prognosis.
STUDY DESIGN RATIONALE A parallel-group design was chosen over a crossover design to avoid carry-over effects, as aerobic training adaptations may persist for weeks after program completion. Assessor and statistical analyst blinding is implemented to minimize detection and analysis bias; blinding of the treating physiotherapist is not feasible given the nature of the intervention.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Double (Investigator, Outcomes Assessor)
盲法说明
In addition to blinding the outcome assessor and the statistical analyst, no masking will be applied to other parties involved in the study. Due to the practical nature of the intervention, the personnel responsible for administering the training (physiotherapists) and the participants themselves will be aware of group allocation. Blinding of the intervention providers or the participants is not planned.
Thus, the only blinding implemented will be that of the assessor and the analyst, ensuring objectivity in outcome measurement and data analysis, and minimizing potential bias in these processes.
入排标准
- 年龄范围
- 40 Years 至 75 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Confirmed diagnosis of cardiovascular disease requiring cardiac rehabilitation, with medical indication for a supervised exercise training program.
- •Prognostic risk classified as low or moderate according to the clinical risk stratification established in the unit, considering:
- •Killip class I or II (absence or mild heart failure)¹.
- •Absence of recent acute myocardial infarction (< 1 month) or presence of a stable previous infarction.
- •Stable and well-controlled cardiovascular symptoms.
- •Physical capacity demonstrated in functional tests ≥ 5 METs, preferably > 7 METs for low-risk patients.
- •Age between 40 and 75 years.
- •Ability to perform physical exercise without absolute contraindications.
- •Written informed consent and willingness to attend the scheduled sessions twice per week for 8 weeks.
排除标准
- •High prognostic risk, defined by:
- •Killip class > III (moderate to severe heart failure).
- •Recent acute myocardial infarction (< 1 month) with clinical instability.
- •Active anginal symptoms or decompensated heart failure.
- •Physical capacity < 5 METs on functional testing, indicating severely reduced exercise capacity.
- •Presence of complex or unstable arrhythmias contraindicating vigorous physical exercise.
- •Concomitant diseases that may limit participation or compromise safety (e.g., advanced pulmonary disease, severe renal failure, severe neuromuscular disorders).
- •Absolute medical contraindications to maximal strength or interval training (e.g., aortic aneurysm, uncontrolled hypertension).
- •Participation in another clinical trial or concurrent rehabilitation program.
- •Inability to comply with attendance requirements or to follow the intervention protocol.
结局指标
主要结局
Change in heart rate-power slope during a submaximal incremental cycling test
时间窗: Baseline (Week 0), Post-intervention (Week 8), and Follow-up (Week 12)
The heart rate-power slope will be assessed during a submaximal incremental cycling test performed on a cycle ergometer. The protocol will start at 20 W, with workload increases of 10 W every 2 minutes until submaximal termination criteria are reached. Heart rate will be continuously monitored using a validated chest strap device. The heart rate-power slope will be calculated as: (Heart rate\_initial - Heart rate\_final) / (Power\_initial - Power\_final) The result will be expressed in beats per minute per watt (bpm/W). Higher values indicate reduced cardiovascular efficiency.
次要结局
未报告次要终点
研究者
Isidro Fernández López
PT, PhD.
Universidad Complutense de Madrid