Henderson K K, Clancy R L, Gonzalez N C
Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160-7401, USA.
J Appl Physiol (1985). 2001 Jun;90(6):2057-62. doi: 10.1152/jappl.2001.90.6.2057.
The objective of these experiments was to determine whether living and training in moderate hypoxia (MHx) confers an advantage on maximal normoxic exercise capacity compared with living and training in normoxia. Rats were acclimatized to and trained in MHx [inspired PO2 (PI(O2)) = 110 Torr] for 10 wk (HTH). Rats living in normoxia trained under normoxic conditions (NTN) at the same absolute work rate: 30 m/min on a 10 degrees incline, 1 h/day, 5 days/wk. At the end of training, rats exercised maximally in normoxia. Training increased maximal O2 consumption (VO2 max) in NTN and HTH above normoxic (NS) and hypoxic (HS) sedentary controls. However, VO2 max and O2 transport variables were not significantly different between NTN and HTH: VO2 max 86.6 +/- 1.5 vs. 86.8 +/- 1.1 ml x min(-1) x kg(-1); maximal cardiac output 456 +/- 7 vs. 443 +/- 12 ml x min(-1) x kg(-1); tissue blood O2 delivery (cardiac output x arterial O2 content) 95 +/- 2 vs. 96 +/- 2 ml x min(-1) x kg(-1); and O2 extraction ratio (arteriovenous O2 content difference/arterial O2 content) 0.91 +/- 0.01 vs. 0.90 +/- 0.01. Mean pulmonary arterial pressure (Ppa, mmHg) was significantly higher in HS vs. NS (P < 0.05) at rest (24.5 +/- 0.8 vs. 18.1 +/- 0.8) and during maximal exercise (32.0 +/- 0.9 vs. 23.8 +/- 0.6). Training in MHx significantly attenuated the degree of pulmonary hypertension, with Ppa being significantly lower at rest (19.3 +/- 0.8) and during maximal exercise (29.2 +/- 0.5) in HTH vs. HS. These data indicate that, despite maintaining equal absolute training intensity levels, acclimatization to and training in MHx does not confer significant advantages over normoxic training. On the other hand, the pulmonary hypertension associated with acclimatization to hypoxia is reduced with hypoxic exercise training.
这些实验的目的是确定与在常氧环境中生活和训练相比，在中度低氧环境（MHx）中生活和训练是否能赋予最大常氧运动能力优势。将大鼠置于MHx环境[吸入氧分压（PI(O2)）= 110 Torr]中适应并训练10周（HTH）。生活在常氧环境中的大鼠在相同的绝对工作强度下于常氧条件下训练（NTN）：在10度斜坡上以30米/分钟的速度运动，每天1小时，每周5天。训练结束时，大鼠在常氧环境中进行最大强度运动。训练使NTN组和HTH组的最大耗氧量（VO2 max）高于常氧（NS）和低氧（HS）静息对照组。然而，NTN组和HTH组之间的VO2 max和氧运输变量没有显著差异：VO2 max分别为86.6±1.5与86.8±1.1毫升·分钟⁻¹·千克⁻¹；最大心输出量分别为45,6±7与⁻443±12毫升·分钟⁻¹·千克⁻¹；组织血液氧输送（心输出量×动脉血氧含量）分别为95±2与96±2毫升·分钟⁻¹·千克⁻¹；氧摄取率（动静脉血氧含量差/动脉血氧含量）分别为0.91±0.01与0.90±0.01。静息时（24.5±0.8与18.1±0.8）和最大运动时（32.0±0.9与23.8±0.6），HS组的平均肺动脉压（Ppa，mmHg）显著高于NS组（P < 0.05）。在MHx环境中训练显著减轻了肺动脉高压的程度，HTH组静息时（19.3±0.8）和最大运动时（29.2±0.5）的Ppa显著低于HS组。这些数据表明，尽管保持相同的绝对训练强度水平，但在MHx环境中适应和训练并不比常氧训练具有显著优势。另一方面，与低氧适应相关的肺动脉高压可通过低氧运动训练减轻。
