拉萨健康藏汉族青年运动时颈内动脉血流速度的变化

CHANGES IN CAROTID ARTERIAL FLOW VELOCITY DURING EXERCISE IN TIBETAN AND HAN HEALTHY RESIDENTS IN LHASA

应用多普勒超声法测定了拉萨市１５名健康男性世居藏族和１１名健康男性移居汉族静息时的颈内动脉平均血流速度（ＩＣＡＭＦＶ）；以了解高原居民运动时ＩＣＡＭＦＶ、脑血流（ＣＢＦ）和脑氧供应量的状况。结果表明：静息时两组ＩＣＡＭＦＶ、ＣＢＦ及脑氧供应量相似；次极量运动时，两组的ＩＣＡＭＦＶ和脑氧供应量均增加；但在最大运动负荷时，仅世居组的ＩＣＡＭＦＶ及脑氧供应量增加。ＩＣＡＭＦＶ的增加可代偿最大运动时因ＳａＯ２降低所致的脑氧供应量下降。最大运动时世居组的脑氧供应量高于移居组，主要以ＣＢＦ增加同时与维持较高的ＳａＯ２有关。脑氧供应量的增加可能与提高最大运动负荷能力有关。结果说明长期居住于高原的世居人和移居人运动时ＣＢＦ反应己恢复到与平原相似的正常状态。

Fifteen male Tibetan native healthy residents versus ll acclimatized healthy male Hans ofLhasa(alt=3 658 m, PB=52.3 kPa)were studied to determine whether the cerebral blood flowincreased during exercise. The Tibetans and Hans were matched for age,body size, resting bloodpressure,hemoglobin concentration, and diameter of the internal carotid artery.NoninvasiveDoppler ultrasonograph was used to measure internal carotid arterial mean flow velocity(ICAMFV) and to assess cerebral blood flow(CBF) and cerebral O2 delivery.ICAMFV and cer-ebral O2 delivery were similar in the two groups at rest.The ICAMFVand cerebral O2 deliveryincreased in Tibetan and Han groups during submaximal exercise workload.At maximal efforts,the Tibetan retained the increase in ICAM FV and cerebral O2 delivery but the Han did not.Greater cerebral O2 delivery was associated with increased maximal exercise performance in theTibetan as compared with the Han group. The findings suggest that the CBF response to exerciseis restored to nearly normal after long─term residence at high altitude.