[The characteristics and changes in high altitude ventilatory response during acclimatization at 5000 meters altitude].

To assess the characteristics and changes of high altitude ventilation response during acclimatization at 5000m altitude. The poikilocapnic hypoxic ventilatory responses (PHVR) were tested on nineteen healthy men who sojourned 5000m altitude for 12 weeks. The results were that there was a linear correlation between predicated ventilations which were calculated for 5000m altitude depended on PHVR values before ascent and actual ventilations tested when arrived at altitude. The PHVR was increased at second week after ascent, but at twelth week it was dropped near the level before ascent. The authors thought that peripheral chemoreceptor function might be enhanced within a period after ascent. With the acclimatization becomes perfected, the role of compensatory hyperventilation drops gradually to secondary position. So the activity of the chemoreceptor was restored gradually. The PHVR values in Xining group were lower than that in sea level group before ascent, but opposite change appeared at second week at 5000m altitude. There were no significant difference in PHVR between with and without acute mountain sickness groups.