OXYGEN-TRANSPORT TO EXERCISING LEG IN CHRONIC HYPOXIA
OXYGEN-TRANSPORT TO EXERCISING LEG IN CHRONIC HYPOXIA
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DOI：
10.1152/jappl.1988.65.6.2592
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发表时间：
1988-12-01
影响因子：
3.3
通讯作者：
REEVES, JT
中科院分区：
文献类型：
--
作者：
BENDER, PR;GROVES, BM;REEVES, JT
居住在高海拔地区可能伴随着适应，改变O2输送到运动肌肉的机制。7名海平面居民男性，年龄22岁。1年，在海平面常氧[吸入PO 2（PIO 2）150 Torr]和急性低压缺氧条件下进行中度至接近最大稳态循环运动（大气压，445托; PIO 2，83 Torr），并在Pikes Peak（4，300 m）上停留18天，同时呼吸环境空气（PIO 2，86托）和空气类似于在海平面（35%O2，144托）。在低氧和常氧条件下，习服后股动脉-髂静脉氧含量差、血红蛋白浓度和动脉氧含量均高于习服前，但静脉氧分压（PvO 2）无变化。热稀释腿部血流量较低，但计算的动脉O2输送和腿部VO 2在低氧适应后与适应前相似。平均动脉压（MAP）和总外周阻力在低氧习服后，大于之前，习服。我们的结论是，适应并没有增加O2输送，而是通过增加动脉氧合和减少腿部血流量来维持输送。PvO 2的维持和适应后较高的MAP表明O2输送与组织O2需求相匹配，血管收缩可能导致流量下降。
Residence at high altitude could be accompanied by adaptations that alter the mechanisms of O2 delivery to exercising muscle. Seven sea level resident males, aged 22 .+-. 1 yr, performed moderate to near-maximal steady-state cycle exercise at sea level in normoxia [inspired PO2 (PIO2) 150 Torr] and acute hypobaric hypoxia (barometric pressure, 445 Torr; PIO2, 83 Torr) and after 18 days'' residence on Pikes Peak (4,300 m) while breathing ambient air (PIO2, 86 Torr) and air similar to that at sea level (35% O2, 144 Torr). In both hypoxia and normoxia, after acclimatization the femoral arterial-iliac venous O2 content difference, hemoglobin concentration, and arterial O2 content, were higher than before acclimatization, but the venous PO2 (PvO2) was unchanged. Thermodilution leg blood flow was lower but calculated arterial O2 delivery and leg .ovrhdot.VO2 similar in hypoxia after vs. before acclimatization. Mean arterial pressure (MAP) and total peripheral resistance in hypoxia were greater after, than before, acclimatization. We concluded that acclimatization did not increase O2 delivery but rather maintained delivery via increased arterial oxygenation and decreased leg blood flow. The maintenance of PvO2 and the higher MAP after acclimatization suggested matching of O2 delivery to tissue O2 demands, with vasoconstriuction possibly contributing to the decreasd flow.