Timmons Brian W, Bar-Or Oded, Riddell Michael C
Children's Exercise and Nutrition Centre, McMaster University, Hamilton L8N 3Z5, Canada M3J 1P3.
J Appl Physiol (1985). 2003 Jan;94(1):278-84. doi: 10.1152/japplphysiol.00140.2002. Epub 2002 Sep 13.
To determine whether the relative utilization of exogenous carbohydrate (CHO(exo)) differs between children and adults, substrate utilization during 60 min of cycling at 70% peak O(2) uptake was studied in 12 pre- and early pubertal boys (9.8 +/- 0.1 yr) and 10 men (22.1 +/- 0.5 yr) on two occasions. Subjects consumed either a placebo or a (13)C-enriched 6% CHO(exo) beverage (total volume per trial: 24 ml/kg). Substrate utilization was calculated for the final 30 min of exercise. During both trials, total fat oxidation was higher (5.4 +/- 0.5 vs. 3.0 +/- 0.4 mg x kg(-1) x min(-1), P < 0.001) and total CHO oxidation lower (27.4 +/- 1.5 vs. 34.8 +/- 1.2 mg x kg(-1) x min(-1), P < 0.001) in boys than in men, respectively. During the CHO(exo) trial, CHO(exo) oxidation was higher (P < 0.001) in boys (8.8 +/- 0.5 mg x kg(-1) x min(-1)) than in men (6.2 +/- 0.5 mg x kg(-1) x min(-1)) and provided a greater (P < 0.001) relative proportion of total energy in boys (21.8 +/- 1.4%) than in men (14.6 +/- 0.9%). These results suggest that, although endogenous CHO utilization during exercise is lower, the relative oxidation of ingested CHO is considerably higher in boys than in men. The greater reliance on CHO(exo) in boys may be important in preserving endogenous fuels and may be related to pubertal status.
为了确定外源性碳水化合物（CHO(exo)）的相对利用率在儿童和成人之间是否存在差异，我们对12名青春期前和青春期早期男孩（9.8±0.1岁）和10名男性（22.1±0.5岁）进行了两次研究，观察他们在以70%峰值摄氧量进行60分钟骑行过程中的底物利用情况。受试者分别饮用了安慰剂或富含¹³C的6% CHO(exo)饮料（每次试验的总体积：24 ml/kg）。计算运动最后30分钟的底物利用率。在两次试验中，男孩的总脂肪氧化均高于男性（分别为5.4±0.5 vs. 3.0±0.4 mg·kg⁻¹·min⁻¹，P<0.001），总碳水化合物氧化低于男性（分别为27.
