RESUMEN
BACKGROUND: Exaggerated sympathetic nervous system activity associated with low heart rate variability (HRV) is considered to trigger cardiac arrhythmias and sudden death. Regular exercise training is efficient to improve autonomic balance. OBJECTIVE: We aimed to verify the superiority of high-intensity interval training (HIIT) to enhance HRV, cardiorespiratory fitness and cardiac function as compared with moderate intensity continuous training (MICT) in a short, intense cardiac rehabilitation program. METHODS: This was a prospective, monocentric, evaluator-blinded, randomised (1:1) study with a parallel two-group design. Overall, 31 individuals with voluntary chronic heart failure (CHF) (left ventricular ejection fraction [LVEF]<45%) were allocated to MICT (n=15) or HIIT (n=16) for a short rehabilitation program (mean [SD] 27 [4] days). Participants underwent 24-hr electrocardiography, echocardiography and a cardiopulmonary exercise test at entry and at the end of the study. RESULTS: High-frequency power in normalized units (HFnu%) measured as HRV increased with HIIT (from 21.2% to 26.4%, P<0.001) but remained unchanged with MICT (from 23.1% to 21.9%, P=0.444, with a significant intergroup difference, P=0.003). Resting heart rate (24-hr Holter electrocardiography) decreased significantly for both groups (from 68.2 to 64.6 bpm and 66.0 to 63.5 bpm for MICT and HIIT, respectively, with no intergroup difference, P=0.578). The 2 groups did not differ in premature ventricular contractions. Improvement in peak oxygen uptake was greater with HIIT than MICT (+21% vs. +5%, P=0.009). LVEF improved with only HIIT (from 36.2% to 39.5%, P=0.034). CONCLUSIONS: In this short rehabilitation program, HIIT was significantly superior to the classical MICT program for enhancing parasympathetic tone and peak oxygen uptake. CLINICALTRIALS. GOV IDENTIFIER: NCT03603743.
Asunto(s)
Rehabilitación Cardiaca/métodos , Ejercicio Físico/fisiología , Insuficiencia Cardíaca/rehabilitación , Frecuencia Cardíaca/fisiología , Entrenamiento de Intervalos de Alta Intensidad/métodos , Anciano , Enfermedad Crónica , Femenino , Insuficiencia Cardíaca/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno/fisiología , Estudios Prospectivos , Volumen Sistólico/fisiología , Resultado del TratamientoRESUMEN
OBJECTIVE: To assess the efficacy of a strategy, based on telephone support oriented by accelerometer measurements, on the adherence to physical activity (PA) recommendations in cardiac patients not achieving PA recommendations. DESIGN: Prospective and randomized study. SETTING: A cardiac rehabilitation program (CRP) at a clinic. PARTICIPANTS: Stable, noncompliant cardiac (coronary artery disease, heart failure, post-cardiovascular surgery) patients (weekly moderate-intensity PA <150 min) were randomly assigned to an intervention group (n=19) or a control group (n=10). INTERVENTIONS: The intervention group wore an accelerometer for 8 weeks. Every 15 days, feedback and support were provided by telephone. The control group wore the accelerometer during the 8th week of the intervention only. MAIN OUTCOME MEASURES: Active energy expenditure (EE) (in kilocalories) and the time spent doing light, moderate, or intense PA (minutes per week). RESULTS: In the intervention group, the time spent at moderate-intensity PA increased from 95.6±80.7 to 137.2±87.5 min/wk between the 1st and 8th week (P=.002), with 36.8% of the sample achieving the target amount of moderate-intensity PA. During the 8th week, the EE averaged 543.7±144.1 kcal and 266.7±107.4 kcal in the intervention group and control group, respectively (P=.004). CONCLUSIONS: Telephone support based on accelerometer recordings appeared to be an effective strategy to improve adherence to PA in noncompliant patients. This intervention could be implemented after a CRP as an inexpensive, modern, and easy-to-use strategy.