Human Adaptation to the Tibetan Plateau

摘要

Humans live at high altitude for longer periods of time on the Tibetan Plateau than elsewhere in the world, thus providing opportunity to investigate the physiologic effects of longer (years to generations) duration of high altitude exposure. This has military importance because persons are stationed at high altitude locations for extended periods and some of the symptoms of failure to adjust to high altitude require months or years for development. We have completed two field projects (Fall 1987 and 1988) which suggest that Tibetans (natives) possess superior O2 transport and/or utilization systems compared to acclimatized newcomers ('Han Chinese'). Studies conducted in the period covered by this report addressed the control of breathing and blood oxygenation during sleep. In 22 healthy young men (11 Tibetans, 11 Hans), measurements of the control of breathing and lung volume during wakefulness were examined together with nighttime studies of breathing and brain blood flow during sleep. Similar, additional studies were carried out in 8 principally Han patients with chronic mountain sickness and 8 age-matched healthy controls. The data analysis from these studies is not yet complete but suggests that the Tibetans' greater lung volume, ventilatory sensitivity to hypoxia and high frequency respiratory pattern may confer protection against sleep-disordered breathing and thus better pressure blood oxygenation during sleep. Keywords: High altitude; O2 Transport; Hypoxia ventilation; Blood flow; Altitude illness. (kt)