RESUMEN
This study examined the influence of maturation on the oxygen uptake efficiency slope (OUES) in healthy male subjects. Seventy-six healthy male subjects (8-27 yr) were divided into groups based on maturation status: prepubertal (PP), midpubertal (MP), late-pubertal (LP), and young-adult (YA) males. Puberty status was determined by physical examination. Subjects performed a graded exercise test on a cycle ergometer to determine OUES. Group differences were assessed using a one-way ANOVA. OUES values (VO(2)L·min(-1)/log(10)V(E)L·min(-1)) were lower in PP and MP compared with LP and YA (p < .05). When OUES was expressed relative to body mass (VO(2)mL·kg-1·min(-1)/log(10)V(E)mL·kg(-1)·min(-1)) differences between groups reversed whereby PP and MP had higher mass relative OUES values compared with LP and YA (p < .05). Adjusting OUES by measures of body mass failed to eliminate differences across maturational groups. This suggests that qualitative factors, perhaps related to oxidative metabolism, account for the responses observed in this study.
Asunto(s)
Consumo de Oxígeno/fisiología , Pubertad/fisiología , Ventilación Pulmonar/fisiología , Maduración Sexual/fisiología , Adolescente , Adulto , Análisis de Varianza , Índice de Masa Corporal , Niño , Estudios Transversales , Prueba de Esfuerzo , Humanos , Masculino , Espirometría , Adulto JovenRESUMEN
The effect of stimulant medication use by children with attention deficit/hyperactivity disorder (ADHD) on the rating of perceived exertion (RPE)-heart rate (HR) relationship was examined. Children with ADHD (n=20; 11.3±1.8 yrs) and children without ADHD (n=25; 11.2±2.1 yrs) were studied. Children with ADHD were examined while on their usual dose of medication on the day of study. HR and RPE, using the OMNI RPE scale, were assessed during a graded exercise to peak voluntary effort. The RPE-HR relationship was determined individually and the intercept and slope responses were compared between groups. The intercept was 132.4±19.5 bpm for children with ADHD and 120.6±15.7 bpm for children without ADHD. The slope was 7.3±1.9 bpm/RPE for the children with ADHD and 8.1±1.6 bpm/ RPE for the children without ADHD. For the group with ADHD the intercept and slope values fell outside of the 95% CI observed in the control group. The altered relationship between RPE and HR with stimulant medication use in children with ADHD has practical implications with respect to the use of HR and RPE to monitor exercise intensity.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Estimulantes del Sistema Nervioso Central/administración & dosificación , Prueba de Esfuerzo/métodos , Frecuencia Cardíaca/efectos de los fármacos , Esfuerzo Físico/efectos de los fármacos , Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Estudios de Casos y Controles , Niño , Intervalos de Confianza , Relación Dosis-Respuesta a Droga , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Modelos Lineales , Masculino , Percepción/fisiología , Esfuerzo Físico/fisiología , Valores de Referencia , Sensibilidad y Especificidad , Índice de Severidad de la EnfermedadRESUMEN
OBJECTIVE: The effect of stimulant medication on exercise responses was studied in 14 boys (10.9 +/- 1.1 years) with attention deficit/hyperactivity disorder (ADHD). METHOD: Exercise, with and without medication, was performed at 25 W, 50 W, and 75 W, followed by a peak exercise test. RESULT: Submaximal heart rate (HR) was significantly higher by ~8 to 13 b.min(-1) across the three intensities during the medication trial, but oxygen uptake (VO(2)), respiratory exchange ratio (RER), and perceived exertion were similar (p > .05). At peak exercise, VO(2), HR, and work rate were attenuated (p < or = .05) in the absence of medication but not RER or perceived exertion. The decreased peak exercise responses were apparent in 6 of 13 participants. CONCLUSION: Stimulant medication raises submaximal HR but does not affect other cardiorespiratory measures or perceived exertion. Without medication physiological responses at peak exercise are attenuated in some but not all boys with ADHD.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Estimulantes del Sistema Nervioso Central/uso terapéutico , Ejercicio Físico , Frecuencia Cardíaca/fisiología , Metilfenidato/uso terapéutico , Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Niño , Humanos , Masculino , Índice de Severidad de la Enfermedad , Factores de Tiempo , Resultado del TratamientoRESUMEN
This study examined substrate use during exercise in early-pubertal (EP), mid-pubertal (MP), late-pubertal (LP), and young-adult (YA) males. Fuel use was calculated using the RER and VO2 response during cycling exercise at 30 to 70% of VO2speak. Significant group by intensity interactions were found for lactate, RER, percent CHO, and fat use, in addition to fat and CHO oxidation rates, which suggest a maturation effect on substrate use during exercise. While significance was not achieved at all intensities, post hoc analyses revealed greater fat use, lower CHO use, and lower lactate concentrations in EP and MP compared to LP or YA. No differences were noted between EP and MP or LP and YA at any intensity, suggesting the development of an adult-like metabolic profile occurs between mid- to late-puberty and is complete by the end of puberty.