Friedlander A L, Casazza G A, Horning M A, Huie M J, Brooks G A
Department of Human Biodynamics, University of California, Berkeley 94720, USA.
J Appl Physiol (1985). 1997 Apr;82(4):1360-9. doi: 10.1152/jappl.1997.82.4.1360.
We examined the hypothesis that glucose flux was directly related to relative exercise intensity both before and after a 10-wk cycle ergometer training program in 19 healthy male subjects. Two pretraining trials [45 and 65% of peak O2 consumption (VO2peak)] and two posttraining trials (same absolute and relative intensities as 65% pretraining) were performed for 90 min of rest and 1 h of cycling exercise. After training, subjects increased VO2peak by 9.4 +/- 1.4%. Pretraining, the intensity effect on glucose kinetics was evident with rates of appearance (R(a); 5.84 +/- 0.23 vs. 4.73 +/- 0.19 mg x kg(-1) x min(-1)), disappearance (R(d); 5.78 +/- 0.19 vs. 4.73 +/- 0.19 mg x kg(-1) x min(-1) x min(-1)), oxidation (R(ox); 5.36 +/- 0.15 vs. 3.41 +/- 0.23 mg x kg(-1) x min(-1)), and metabolic clearance (7.03 +/- 0.56 vs. 5.20 +/- 0.28 ml x kg(-1) x min(-1)) of glucose being significantly greater (P < or = 0.05) in the 65% than the 45% VO2peak trial. When R(d) was expressed as a percentage of total energy expended per minute (R(dE)), there was no difference between the 45 and 65% intensities. Training did reduce R(a) (4.63 +/- 0.25), R(d) (4.65 +/- 0.24), R(ox) (3.77 +/- 0.43), and R(dE) (15.30 +/- 0.40 to 12.85 +/- 0.81) when subjects were tested at the same absolute workload (P < or = 0.05). However, when they were tested at the same relative workload, R(a), R(d), and R(dE) were not different, although R(ox) was lower posttraining (5.36 +/- 0.15 vs. 4.41 +/- 0.42, P < or = 0.05). These results show 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 use during exercise; 4) training alters the pathways of glucose disposal.
在19名健康男性受试者进行为期10周的周期测力计训练计划前后，葡萄糖通量与相对运动强度直接相关。进行了两次训练前试验[峰值耗氧量（VO₂peak）的45%和65%]以及两次训练后试验（绝对强度和相对强度与训练前的65%相同），包括90分钟的休息和1小时的骑行运动。训练后，受试者的VO₂peak增加了9.4±1.4%。训练前，在65%VO₂peak试验中，葡萄糖动力学的强度效应明显，葡萄糖的出现率（R(a)；5.84±0.23对4.73±0.19mg·kg⁻¹·min⁻¹）、消失率（R(d)；5.78±0.19对4.73±0.19mg·kg⁻¹·min⁻¹）、氧化率（R(ox)；5.36±0.15对3.41±0.23mg·kg⁻¹·min⁻¹）和代谢清除率（7.03±0.56对5.20±0.28ml·kg⁻¹·min⁻¹）均显著更高（P≤0.05）。当将R(d)表示为每分钟总能量消耗的百分比（R(dE)）时，45%和65%强度之间没有差异。当受试者在相同绝对工作量下进行测试时，训练确实降低了R(a)（4.63±0.25）、R(d)（4.65±0.24）、R(ox)（3.77±0.43）和R(dE)（15.30±0.40至12.85±0.81）（P≤0.05）。然而，当他们在相同相对工作量下进行测试时，R(a)、R(d)和R(dE)没有差异，尽管训练后R(ox)较低（5.36±0.15对4.41±0.42，P≤0.05）。这些结果表明：1）葡萄糖利用与运动强度直接相关；2）训练可降低给定功率输出下的葡萄糖通量；3）当表示为相对运动强度时，训练不影响运动期间血糖利用的幅度；4）训练改变了葡萄糖处置途径。
