Huang S Y, Tawney K W, Bender P R, Groves B M, McCullough R E, McCullough R G, Micco A J, Manco-Johnson M, Cymerman A, Greene E R
Cardiovascular Pulmonary Laboratory, University of Colorado Health Sciences Center, Denver 80262.
J Appl Physiol (1985). 1991 Oct;71(4):1469-76. doi: 10.1152/jappl.1991.71.4.1469.
Cerebral blood flow and O2 delivery during exercise are important for well-being at altitude but have not been studied. We expected flow to increase on arrival at altitude and then to fall as O2 saturation and hemoglobin increased, thereby maintaining cerebral O2 delivery. We used Doppler ultrasound to measure internal carotid artery flow velocity at sea level and on Pikes Peak, CO (4,300 m). In an initial study (1987, n = 7 men) done to determine the effect of brief (5-min) exercises of increasing intensity, we found at sea level that velocity [24.8 +/- 1.4 (SE) cm/s rest] increased by 15 +/- 7, 30 +/- 6, and 22 +/- 8% for cycle exercises at 33, 71, and 96% of maximal O2 uptake, respectively. During acute hypobaric hypoxia in a decompression chamber (inspired PO2 = 83 Torr), velocity (23.2 +/- 1.4 cm/s rest) increased by 33 +/- 6, 20 +/- 5, and 17 +/- 9% for exercises at 45, 72, and 98% of maximal O2 uptake, respectively. After 18 days on Pikes Peak (inspired PO2 = 87 Torr), velocity (26.6 +/- 1.5 cm/s rest) did not increase with exercise. A subsequent study (1988, n = 7 men) of the effect of prolonged exercise (45 min at approximately 100 W) found at sea level that velocity (24.8 +/- 1.7 cm/s rest) increased by 22 +/- 6, 13 +/- 5, 17 +/- 4, and 12 +/- 3% at 5, 15, 30, and 45 min.(ABSTRACT TRUNCATED AT 250 WORDS)
运动期间的脑血流量和氧气输送对高原地区的健康很重要，但尚未得到研究。我们预计到达高原时血流量会增加，然后随着氧气饱和度和血红蛋白的增加而下降，从而维持脑部的氧气输送。我们使用多普勒超声测量海平面和科罗拉多州派克斯峰（4300米）处颈内动脉的血流速度。在一项初步研究（1987年，7名男性）中，为了确定强度递增的短暂（5分钟）运动的效果，我们发现在海平面上，静息时速度为[24.8±1.4（标准误）厘米/秒]，在最大摄氧量的33%、71%和96%的自行车运动中，速度分别增加了15±7%、30±6%和22±8%。在减压舱的急性低压缺氧期间（吸入氧分压=83托），静息时速度为（23.2±1.4厘米/秒），在最大摄氧量的45%、72%和98%的运动中，速度分别增加了33±6%、20±5%和17±9%。在派克斯峰停留18天后（吸入氧分压=87托），速度（静息时26.6±1.5厘米/秒）并未随运动增加。随后的一项研究（1988年，7名男性），研究了长时间运动（约100瓦，45分钟）的效果，发现在海平面上，静息时速度为（24.8±1.7厘米/秒），在5、15、30和45分钟时分别增加了22±6%、13±5%、17±4%和12±3%。（摘要截选至250字）
