Oxygen uptake of overweight and obese children at different stages of a progressive treadmill test. (Consumo de oxígeno de niños y niñas con sobrepeso y obesos en los diferentes estadios de una prueba progresiva en un tapiz rodante).

Resumen

Abstract

Introduction: Maximal oxygen uptake (VO2 max) is associated with cardiovascular and metabolic risks but it is difficult to assess in obese children. The objective of this study was to develop an equation to estimate VO2 (mL/kg/min) and to check the % of tests that were maximal according to recommended criteria. Methods: Stress tests were analyzed of 222 subjects (94 male and 128 female with a BMI above the 85 percentile for age and sex), and repeated 4 months later. Mean age was 9.4 + 1.1 years and weighed 52.4 + 13.3 kg. Body fat % (40.5 + 6.2) was determined by DXA (Hologic QDR 4500W). The protocol on the treadmill started with a warm up at 2.5 and 3 mph with a slope of 0% and 2%. The speed was kept at 3 mph for all the stages and the slope was increased 2% every 2 minutes. Statistical analysis (descriptive, t-test and ANOVAS 2x2x2) was done with SPSS 15.0. Results: Only 35% of the tests were maximal. The equation calculates was Y = 2.6x + 22.3 (x = protocol stage). Data pre and post treatment were not statistically different. Discussion: Increments in VO2 were consistent despite subject diversity (sex, % body fat, physical fitness, treatment). Conclusion: To be able to estimate VO2 at the different stages of the test without complex equipment or specialized staff, will facilitate the performance of stress tests on a daily basis.

Key words: Childhood obesity and overweight, estimation of VO2, stress test protocols.

Resumen

Introducción: El consumo máximo de oxígeno (VO2 max) está asociado con riesgos cardiovasculares y metabólicos pero resulta difícil valorarlo en niños y niñas obesos. El objetivo de este trabajo fue desarrollar una ecuación para estimar su VO2 (mL/kg/min) y comprobar el porcentaje de pruebas máximas según los criterios recomendados. Métodos: Se analizaron las pruebas de esfuerzo de 222 sujetos (94 varones y 128 mujeres con un IMC superior al percentil 85 para su edad y sexo), y las repetidas a los 4 meses. Su edad era 9,4 + 1,1 años y pesaban 52,4 + 13,3 kg. El % de grasa corporal (40,5 + 6,2) se determinó mediante DXA (Hologic QDR 4500W). El protocolo del tapiz rodante comenzó calentando a 4,02 km/h y a 4,83 km/h con pendientes del 0% y 2%. La velocidad se mantuvo a 4,83 km/h en los estadíos de la prueba incrementando la pendiente un 2% cada 2 minutos. El análisis estadístico (descriptivo, t-tests y ANOVAS 2x2x2) se realizó con SPSS 15.0. Resultados: Sólo 35% de las pruebas resultaron máximas. La ecuación resultante fue Y = 2,6x + 22,3 (x = estadío del protocolo). Los datos pre y post tratamiento no mostraron diferencias significativas. Discusión: Los incrementos del VO2 resultaron consistentes a pesar de la diversidad de los sujetos (sexo, % de grasa, niveles de condición física, tratamiento). Conclusión: Poder estimar el VO2 en los distintos estadíos de la prueba sin necesidad de equipos complejos, caros, y personal especializado, facilitará la realización de pruebas de esfuerzos en la práctica diaria.

Palabras clave: estimación del VO2; obesidad y sobrepeso infantil; protocolos de pruebas de esfuerzo.

doi:10.5232/ricyde2010.01805

PMID 21218170 - click here to show this article in PubMed database

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