Leijssen D P, Saris W H, Jeukendrup A E, Wagenmakers A J
Department of Human Biology, University of Limburg, Maastricht, The Netherlands.
J Appl Physiol (1985). 1995 Sep;79(3):720-5. doi: 10.1152/jappl.1995.79.3.720.
The present study examined the oxidation of exogenous galactose or glucose during prolonged submaximal cycling exercise. Eight highly trained volunteers exercised on two occasions on a cycle ergometer at 65% of maximal workload for 120 min, followed by a 60-min rest period and a second exercise bout of 30 min at 60% maximal workload. At random, subjects ingested a 8% galactose solution to which an [1-13C]galactose tracer was added or a 8% glucose solution to which an [U-13C]glucose tracer was added. Drinks were provided at the end of the warm-up period (8 ml/kg) and every 15 min (2 ml/kg) during the first 120 min of the test. Blood and breath samples were collected every 30 and 15 min, respectively, during the test. The exogenous carbohydrate (CHO) oxidation was calculated from the 13CO2/12CO2 ratio and CO2 production of the expired air. Peak exogenous CHO oxidation during exercise for galactose and glucose was 0.41 +/- 0.03 and 0.85 +/- 0.04 g/min, respectively. Total CHO and fat oxidation were not significantly different between the treatments. Forty-six percent of the ingested glucose was oxidized, whereas only 21% of the ingested galactose was oxidized. As a consequence, more endogenous CHO was utilized with galactose than with glucose (124.4 +/- 6.7 and 100.1 +/- 3.6 g, respectively). These results indicate that the oxidation rate of orally ingested galactose is maximally approximately 50% of the oxidation rate of a comparable amount of orally ingested glucose during 120 min of exercise.
本研究考察了长时间次最大强度骑行运动期间外源性半乳糖或葡萄糖的氧化情况。八名训练有素的志愿者在功率自行车上进行了两次运动，第一次以最大负荷的65%运动120分钟，随后休息60分钟，接着以最大负荷的60%进行30分钟的第二次运动。随机地，受试者摄入添加了[1-13C]半乳糖示踪剂的8%半乳糖溶液或添加了[U-13C]葡萄糖示踪剂的8%葡萄糖溶液。在热身期结束时（8毫升/千克）以及测试的前120分钟内每15分钟（2毫升/千克）提供饮料。在测试期间，分别每30分钟和15分钟采集血液和呼气样本。外源性碳水化合物（CHO）氧化通过呼出气体中13CO2/12CO2比值和CO2产生量来计算。运动期间半乳糖和葡萄糖的外源性CHO氧化峰值分别为0.41±0.03克/分钟和0.85±0.04克/分钟。两种处理之间总的CHO和脂肪氧化没有显著差异。摄入的葡萄糖中有46%被氧化，而摄入的半乳糖中只有21%被氧化。因此，与葡萄糖相比，半乳糖运动时利用了更多的内源性CHO（分别为124.4±6.7克和100.1±3.6克）。这些结果表明，在120分钟运动期间，口服摄入的半乳糖氧化速率最大约为等量口服葡萄糖氧化速率的50%。
