RESUMEN
BACKGROUND: High intensity interval training (HIIT) confers superior cardiovascular health benefits to moderate intensity continuous training (MICT) in adults and may be efficacious for improving diminished cardiac function in obese children. The aim of this study was to compare the effects of HIIT, MICT and nutrition advice interventions on resting left ventricular (LV) peak systolic tissue velocity (S') in obese children. METHODS: Ninety-nine obese children were randomised into one of three 12-week interventions, 1) HIIT [nâ¯=â¯33, 4â¯×â¯4â¯min bouts at 85-95% maximum heart rate (HRmax), 3 times/week] and nutrition advice, 2) MICT [nâ¯=â¯32, 44 min at 60-70% HRmax, 3 times/week] and nutrition advice, and 3) nutrition advice only (nutrition) [nâ¯=â¯34]. RESULTS: Twelve weeks of HIIT and MICT were equally efficacious, but superior to nutrition, for normalising resting LV S' in children with obesity (estimated mean difference 1.0â¯cm/s, 95% confidence interval 0.5 to 1.6â¯cm/s, Pâ¯<â¯0.001; estimated mean difference 0.7â¯cm/s, 95% confidence interval 0.2 to 1.3â¯cm/s, Pâ¯=â¯0.010, respectively). CONCLUSIONS: Twelve weeks of HIIT and MICT were superior to nutrition advice only for improving resting LV systolic function in obese children.
Asunto(s)
Entrenamiento de Intervalos de Alta Intensidad , Contracción Miocárdica , Obesidad Infantil/terapia , Disfunción Ventricular Izquierda/terapia , Función Ventricular Izquierda , Adolescente , Factores de Edad , Capacidad Cardiovascular , Niño , Consejo , Dieta Saludable , Ecocardiografía Doppler , Ecocardiografía de Estrés , Femenino , Estado de Salud , Humanos , Masculino , Noruega , Obesidad Infantil/complicaciones , Obesidad Infantil/diagnóstico , Obesidad Infantil/fisiopatología , Queensland , Recuperación de la Función , Factores de Riesgo , Factores de Tiempo , Resultado del Tratamiento , Disfunción Ventricular Izquierda/diagnóstico , Disfunción Ventricular Izquierda/etiología , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
BACKGROUND: Obesity in childhood predisposes individuals to cardiovascular disease and increased risk of premature all-cause mortality. The aim of this study was to determine differences in LV morphology and function in obese and normal-weight adolescents. Furthermore, relationships between LV outcomes, cardiorespiratory fitness (CRF) and adiposity were explored. METHODS: LV morphology was assessed using magnetic resonance imaging (MRI) in 20 adolescents (11 normal-weight [BMI equivalent to 18kg/m2-25kg/m2] and 9 obese [BMI equivalent to ≥30kg/m2]); 13.3±1.1years, 45% female, Tanner puberty stage 3 [2-4]) using magnetic resonance imaging (MRI). Global longitudinal strain (GLS), strain rate (SR) and traditional echocardiographic indices were used to assess LV function. CRF (peak oxygen consumption), percent body fat (dual-energy x-ray absorptiometry), abdominal adipose tissue (MRI), and blood biochemistry markers were also evaluated. RESULTS: Adolescents with obesity showed significantly poorer LV function compared to normal-weight adolescents (P<0.05) indicated by higher GLS (+6.29%) and SR in systole (+0.17s-1), and lower SR in early diastole (-0.61s-1), and tissue Doppler velocities (S' -2.7cm/s; e' -2.3cm/s; A' -1.1cm/s). There were no group differences in LV morphology when indexed to fat free mass (P>0.05). Moderate to strong associations between myocardial contractility and relaxation, adiposity, arterial blood pressure and cardiorespiratory fitness were noted (r=0.49-0.71, P<0.05). CONCLUSION: Obesity in adolescence is associated with altered LV systolic and diastolic function. The notable relationship between LV function, CRF and adiposity highlights the potential utility of multidisciplinary lifestyle interventions to treat diminished LV function in this population. CLINICAL TRIAL REGISTRATION: NCT01991106.