Journal of Applied Physiology, Vol 73, Issue 6 2638-2642, Copyright © 1992 by American Physiological Society

ARTICLES

Internal carotid arterial flow velocity during exercise in Tibetan and Han residents of Lhasa (3,658 m)

S. Y. Huang, S. Sun, T. Droma, J. Zhuang, J. X. Tao, R. G. McCullough, R. E. McCullough, A. J. Micco, J. T. Reeves and L. G. Moore
Shanghai Institute of Physiology, China.

Cerebral blood flow increases with acute exposure to high altitude, but the effect of hypoxia on the cerebral circulation at rest and during exercise appears influenced by the duration of high-altitude exposure. To determine whether internal carotid artery flow velocity increased with exercise in long-term residents of high altitude and whether resting values and the response to exercise differed in lifelong vs. acclimatized newcomer male residents of high altitude, we studied 15 native Tibetan and 11 Han ("Chinese") 6 +/- 2-yr residents of Lhasa (3,658 m), Tibet Autonomous Region, China. Noninvasive Doppler ultrasound was used to measure internal carotid artery diameter, mean flow velocity, and, in combination, hemoglobin and arterial O2 saturation to assess cerebral O2 delivery. Tibetan and Han groups were similar in body size and resting internal carotid artery diameter, blood pressure, hemoglobin concentration, internal carotid artery mean flow velocity, and calculated cerebral O2 delivery. Submaximal exercise increased internal carotid artery mean flow velocity and cerebral O2 delivery in the Tibetan and Han subjects. At peak exercise, the Tibetans sustained the increase in flow velocity and cerebral O2 delivery, whereas the Hans did not. Across all exercise levels up to and including peak effort, the Tibetans demonstrated a greater increase in internal carotid artery flow velocity and cerebral O2 delivery relative to resting values than did the Hans. The greater cerebral O2 delivery was accompanied by increased peak exercise capacity in the Tibetan compared with the Han group. Our findings suggest that the cerebral blood flow response to exercise is maintained in Tibetan lifelong residents of high altitude.

This article has been cited by other articles:

				N. H. Secher, T. Seifert, and J. J. Van Lieshout Cerebral blood flow and metabolism during exercise: implications for fatigue J Appl Physiol, January 1, 2008; 104(1): 306 - 314. [Abstract] [Full Text] [PDF]

				G. F. A. Jansen, A. Krins, B. Basnyat, J. A. Odoom, and C. Ince Role of the altitude level on cerebral autoregulation in residents at high altitude J Appl Physiol, August 1, 2007; 103(2): 518 - 523. [Abstract] [Full Text] [PDF]

				C. M. Beall Colloquium Papers: Two routes to functional adaptation: Tibetan and Andean high-altitude natives PNAS, May 15, 2007; 104(suppl_1): 8655 - 8660. [Abstract] [Full Text] [PDF]

				C. Marconi, M. Marzorati, D. Sciuto, A. Ferri, and P. Cerretelli Economy of locomotion in high-altitude Tibetan migrants exposed to normoxia J. Physiol., December 1, 2005; 569(2): 667 - 675. [Abstract] [Full Text] [PDF]