Limitações da Utilização do Equivalente Metabólico (MET) para Estimativa do Gasto Energético em Atividades Físticas

Abstract

Determining the total energy expenditure is extremely important in the field of health sciences, with the voluntary physical activity the most variable component. This work contextualizes metabolic equivalent (MET), a simple and practical method for estimating the energy expenditure of exercise and physical activity in adults. The MET is based on the resting oxygen consumption value of 3.5 mL/kg/min, but the exact origin of this value is unknown. In contrast, studies in heterogeneous and specific populations (i. e. obese, elderly) show lower values than the default value. Consequently, the energy expenditure in voluntary physical activity may be underestimated, since they are based in the elevation (multiples) of oxygen consumption when compared to the resting state. In this context, recent studies suggest a correction of the value of 1 MET through the Harris-Benedict equation (3.5 ÷ estimated resting metabolic rate (mL/kg/min)), provides a more individualized and accurate estimation of the energy expenditure directly measured (indirect calorimetry). This factor can favor the better planning of nutritional interventions and physical training. Calculations and estimates are always subject to errors due to physical/biological variations among individuals and environmental factors. This factor can favor the better planning of nutritional interventions and physical training. However, does not justify the use of a universal value (1 MET = 3.5 mL/kg/min) for entire population, which results in inadequate estimates of energy expenditure in physical activities. On the other hand, new studies must be carried out so that correction factors may be proposed for specific populations, given that are also controversies between the predictive equations of resting metabolic rate.