Intervenção dietética, metabolismo e desempenho físico de adolescentes

Abstract

The purposes of this study were: 1) to describe the state of the art about the substrate metabolism during exercise in children and adolescents (Review paper), and 2) to investigate the effects of a short-term, isoenergetic fat- or carbohydrate-rich diet on carbohydrate (CHO) and fat oxidation rates during submaximal exercise, and on performance during a 10-km running race in adolescent boys (Original paper). It was found, by review paper, that children and adolescents have a facilitated oxidative metabolism, greater fat utilization rate and greater energy contribution of exogenous CHO, when available, comparable to adults at the same relative exercise intensities. These differences are attributed to particular morphological characteristics, mainly lower endogenous CHO oxidation in younger. From the original paper, it was found that, compared to an isocaloric short-time FAT-rich diet, CHO-rich diet increased the CHO oxidation and improved the 10 km running performance. Nevertheless, adolescents aged 13 to 18 retain a good fat oxidation rate and therefore the 10 km running performance was not negatively affected after 48h FAT-rich dietary intervention when compared to a normal diet. Together, these results suggest that children and adolescents seem to have a well-developed capacity to provide ATP from alternative energy sources such as fat or exogenous CHO, preserving endogenous CHO for their growth and development.