Influencia da suplementação de Aspartato e Asparagina sobre a associação entre os limiares metabolicos e ventilatorios e sobre a taxa de oxidação de nutrientes durante o exercicio

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The anaerobic threshold (A T), defined as the levei of work or the O2 consumption (V02) just below that at which metabolic acidosis and associated changes in gas exchange occur, is composed of a supposed cause-effect association of 2 individual thresholds - lactate or metabolic (MT) and ventilatory (VT). However the proposed mechanisms to explain musclelblood lactate accumulation and cause-effect association of MTNT has been rejected. The aim of this study was to verify the influence of aspartate and asparagine (AA) supplementation on MTNT association (experiment 1; n = 6) and substrate oxidation rates (experiment 2; n = 18). The subjects of both experiments were supplemented with 300mg . kg -1 . day -1 of amino acids (150mg aspartate + 150mg asparagine, AA treatment) and 300mg . kg -1 . day-1 of lactose (PLC treatment) in double blind-crossover fashion prior DIT tests, for 7 days. In the experiment 1, the subjects performed three discontinuous incremental tests (DITs) on cycle ergometer for detection of the MTs, VTs (BASAL, AA and PLC tests). In the experiment 2, the subjects were randomly placed into three groups and submitted to 28-min cycling rides (28R) at the 75% (group SUB), 100% (group SPI) or 115% (group SPII) of the AT 11 workload (watts). The energy expenditure and substrate oxidation rates for group SUB were calculated from respiratory measurements collected at 8, 13, 18, 23 and 28 min from 28R. No significant differences were observed in absolute or relative values for WR, VENT, HR and LA for the comparisons between MTINTI and MTIINTII relationships among test groups (experiment 1). No significant differences were observed for LA during 28R between treatments for the same group. The AA treatment increases the rei ative CHO energy expenditure in 2.284 % (97.531 :!: 4.241% to 99.759 :!: 0.720%; P <.05%) and decreases the relative LlP energy expenditure in -90.239% (2.469:!:: 4.241% to 0.241 : 0.720%, P <.05%) in comparison with PLC treatment, during the SUB28R (experiment 2). We suggest a hypothetic model that involves the increases of [pyruvate]/[Iactate] ratio and PDH activity, promoted for the AA supplementation, to justify the lower LlP oxidation rate during the 28R performed below anaerobic threshold intensity

ASSUNTO(S)

exercicios fisicos oxidação aminoacidos

ACESSO AO ARTIGO

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