Gore C J, Hahn A G, Aughey R J, Martin D T, Ashenden M J, Clark S A, Garnham A P, Roberts A D, Slater G J, McKenna M J
Australian Institute of Sport, Adelaide, South Australia, Australia.
Acta Physiol Scand. 2001 Nov;173(3):275-86. doi: 10.1046/j.1365-201X.2001.00906.x.
This study investigated whether hypoxic exposure increased muscle buffer capacity (beta(m)) and mechanical efficiency during exercise in male athletes. A control (CON, n=7) and a live high:train low group (LHTL, n=6) trained at near sea level (600 m), with the LHTL group sleeping for 23 nights in simulated moderate altitude (3000 m). Whole body oxygen consumption (VO2) was measured under normoxia before, during and after 23 nights of sleeping in hypoxia, during cycle ergometry comprising 4 x 4-min submaximal stages, 2-min at 5.6 +/- 0.4 W kg(-1), and 2-min 'all-out' to determine total work and VO(2peak). A vastus lateralis muscle biopsy was taken at rest and after a standardized 2-min 5.6 +/- 0.4 W kg(-1) bout, before and after LHTL, and analysed for beta(m) and metabolites. After LHTL, beta(m) was increased (18%, P < 0.05). Although work was maintained, VO(2peak) fell after LHTL (7%, P < 0.05). Submaximal VO2 was reduced (4.4%, P < 0.05) and efficiency improved (0.8%, P < 0.05) after LHTL probably because of a shift in fuel utilization. This is the first study to show that hypoxic exposure, per se, increases muscle buffer capacity. Further, reduced VO2 during normoxic exercise after LHTL suggests that improved exercise efficiency is a fundamental adaptation to LHTL.
本研究调查了低氧暴露是否会增加男性运动员运动期间的肌肉缓冲能力（β(m)）和机械效率。一组对照组（CON，n = 7）和一组高住低练组（LHTL，n = 6）在接近海平面（600米）的高度进行训练，其中LHTL组在模拟中度海拔（3000米）睡眠23晚。在低氧睡眠23晚之前、期间和之后，在常氧状态下测量全身耗氧量（VO2），在包括4个4分钟次最大强度阶段的自行车测功试验期间，在5.6±0.4 W kg(-1)强度下持续2分钟，并进行2分钟的“全力”运动以确定总功和VO(2peak)。在LHTL前后，于休息时以及在标准化的2分钟5.6±0.4 W kg(-1)运动 bout 之后，采集股外侧肌活检样本，分析β(m)和代谢产物。LHTL后，β(m)增加（18%，P < 0.05）。尽管功保持不变，但LHTL后VO(2peak)下降（7%，P < 0.05）。LHTL后，次最大强度VO2降低（4.4%，P < 0.05），效率提高（0.8%，P < 0.05），这可能是由于燃料利用的转变。这是第一项表明低氧暴露本身会增加肌肉缓冲能力的研究。此外，LHTL后常氧运动期间VO2降低表明运动效率提高是对LHTL的一种基本适应性变化。
