Perry Christopher G R, Talanian Jason L, Heigenhauser George J F, Spriet Lawrence L
Dept. of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
J Appl Physiol (1985). 2007 Mar;102(3):1022-7. doi: 10.1152/japplphysiol.01215.2006. Epub 2006 Dec 14.
Inspiring a hyperoxic (H) gas permits subjects to exercise at higher power outputs while training, but there is controversy as to whether this improves skeletal muscle oxidative capacity, maximal O(2) consumption (Vo(2 max)), and endurance performance to a greater extent than training in normoxia (N). To determine whether the higher power output during H training leads to a greater increase in these parameters, nine recreationally active subjects were randomly assigned in a single-blind fashion to train in H (60% O(2)) or N for 6 wk (3 sessions/wk of 10 x 4 min at 90% Vo(2 max)). Training heart rate (HR) was maintained during the study by increasing power output. After at least 6 wk of detraining, a second 6-wk training protocol was completed with the other breathing condition. Vo(2 max) and cycle time to exhaustion at 90% of pretraining Vo(2 max) were tested in room air pre- and posttraining. Muscle biopsies were sampled pre- and posttraining for citrate synthase (CS), beta-hydroxyacyl-coenzyme A dehydrogenase (beta-HAD), and mitochondrial aspartate aminotransferase (m-AsAT) activity measurements. Training power outputs were 8% higher (17 W) in H vs. N. However, both conditions produced similar improvements in Vo(2 max) (11-12%); time to exhaustion (approximately 100%); and CS (H, 30%; N, 32%), beta-HAD (H, 23%; N, 21%), and m-AsAT (H, 21%; N, 26%) activities. We conclude that the additional training stimulus provided by training in H was not sufficient to produce greater increases in the aerobic capacity of skeletal muscle and whole body Vo(2 max) and exercise performance compared with training in N.
吸入高氧（H）气体可使受试者在训练时以更高的功率输出进行运动，但对于与常氧（N）训练相比，这是否能更大程度地提高骨骼肌氧化能力、最大摄氧量（Vo₂max）和耐力表现存在争议。为了确定H训练期间更高的功率输出是否会导致这些参数有更大的增加，九名有运动习惯的受试者以单盲方式被随机分配，分别在H（60%氧气）或N环境下训练6周（每周3次，每次10×4分钟，强度为90%Vo₂max）。在研究过程中，通过增加功率输出维持训练心率（HR）。在至少6周的停训期后，以另一种呼吸条件完成第二个6周的训练方案。在训练前后，于室内空气中测试Vo₂max以及达到训练前Vo₂max的90%时的骑行至力竭时间。在训练前后采集肌肉活检样本，用于测量柠檬酸合酶（CS）、β-羟酰基辅酶A脱氢酶（β-HAD）和线粒体天冬氨酸转氨酶（m-AsAT）的活性。与N组相比，H组的训练功率输出高8%（17瓦）。然而，两种条件下Vo₂max（11%-12%）、力竭时间（约100%）以及CS（H组为30%；N组为32%）、β-HAD（H组为23%；N组为21%）和m-AsAT（H组为21%；N组为26%）活性的改善程度相似。我们得出结论，与N训练相比，H训练所提供的额外训练刺激不足以使骨骼肌的有氧能力、全身Vo₂max和运动表现有更大的提高。
