Friedlander A L, Casazza G A, Horning M A, Huie M J, Piacentini M F, Trimmer J K, Brooks G A
Exercise Physiology Laboratory, Department of Integrative Biology, University of California, Berkeley, California 94720-3140, USA.
J Appl Physiol (1985). 1998 Sep;85(3):1175-86. doi: 10.1152/jappl.1998.85.3.1175.
We examined the hypothesis that glucose flux was directly related to relative exercise intensity both before and after a 12-wk cycle ergometer training program [5 days/wk, 1-h duration, 75% peak O2 consumption (VO2 peak)] in healthy female subjects (n = 17; age 23.8 +/- 2.0 yr). Two pretraining trials (45 and 65% of VO2 peak) and two posttraining trials [same absolute workload (65% of old VO2 peak) and same relative workload (65% of new VO2 peak)] were performed on nine subjects by using a primed-continuous infusion of [1-13C]- and [6,6-2H]glucose. Eight additional subjects were studied by using [6, 6-2H]glucose. Subjects were studied postabsorption for 90 min of rest and 1 h of cycling exercise. After training, subjects increased VO2 peak by 25.2 +/- 2.4%. Pretraining, the intensity effect on glucose kinetics was evident between 45 and 65% of VO2 peak with rates of appearance (Ra: 4.52 +/- 0.25 vs. 5.53 +/- 0.33 mg . kg-1 . min-1), disappearance (Rd: 4.46 +/- 0.25 vs. 5.54 +/- 0.33 mg . kg-1 . min-1), and oxidation (Rox: 2.45 +/- 0.16 vs. 4.35 +/- 0.26 mg . kg-1 . min-1) of glucose being significantly greater (P </= 0.05) in the 65% than in the 45% trial. Training reduced Ra (4.7 +/- 0.30 mg . kg-1 . min-1), Rd (4.69 +/- 0.20 mg . kg-1 . min-1), and Rox (3.54 +/- 0.50 mg . kg-1 . min-1) at the same absolute workload (P </= 0. 05). When subjects were tested at the same relative workload, Ra, Rd, and Rox were not significantly different after training. However, at both workloads after training, there was a significant decrease in total carbohydrate oxidation as determined by the respiratory exchange ratio. These results show the following in young women: 1) glucose use is directly related to exercise intensity; 2) training decreases glucose flux for a given power output; 3) when expressed as relative exercise intensity, training does not affect the magnitude of blood glucose flux during exercise; but 4) training does reduce total carbohydrate oxidation.
在一项为期12周的周期测力计训练计划[每周5天，持续1小时，75%的峰值耗氧量（VO₂峰值）]前后，健康女性受试者（n = 17；年龄23.8±2.0岁）的葡萄糖通量与相对运动强度直接相关。对9名受试者进行了两次训练前试验（VO₂峰值的45%和65%）和两次训练后试验[相同的绝对工作量（旧VO₂峰值的65%）和相同的相对工作量（新VO₂峰值的65%）]，通过[1-¹³C]-和[6,6-²H]葡萄糖的预充连续输注进行。另外8名受试者使用[6,6-²H]葡萄糖进行研究。受试者在吸收后进行90分钟的休息和1小时的骑行运动研究。训练后，受试者的VO₂峰值增加了25.2±2.4%。训练前，在VO₂峰值的45%至65%之间，强度对葡萄糖动力学的影响明显，葡萄糖的出现率（Ra：4.52±0.25对5.53±0.33mg·kg⁻¹·min⁻¹）、消失率（Rd：4.46±0.25对5.54±0.33mg·kg⁻¹·min⁻¹）和氧化率（Rox：2.45±
