抄録
Could the intrinsic characteristics of tolerance to hypoxia be retained in Tibetan high-altitude natives after migrating to the low altitude? To answer this question, 33 healthy male adolescent Tibetans were born and grown up in high plateau (3,700 m about see level) and migrated to Shanghai (sea level) for 4 years. Ten aged-matched healthy male Han adolescents born and grown up in Shanghai were regarded as the control group. Acute hypoxia was induced in a hypobaric chamber for 2 h to mimic 3,700 m altitude. At sea level maximal oxygen consumption (VO2 max) was not significant difference between the two groups. During acute hypoxia, the values of VO2 max, tissue oxygen extraction, arterial oxygen pressure, and the arterial oxygen saturation showed markedly higher in Tibetan than Han (1.41 ± 0.04 l/min/M2 vs.1.25 ± 0.04 l/min/M2, 55.0 ± 4.2% vs. 47.3 ± 9.1%, 7.2 ± 0.6 vs. 5.5 ± 0.2 kPa, and 87.9 ± 3.3% vs. 78.2 ± 1.6%, respectively, P < 0.05). The calculated “oxygen reserve capacity” and “cardiac reserve capacity” were better in the Tibetan (P < 0.05). It suggests that physical work capacity is greater in the Tibetan group. The sympathetic stimulation was less and there was not noticeable change in cardiac function during acute hypoxia in the Tibetan group. The results indicate that the better tolerance to hypoxia in the Tibetan is retained with the 4 years stay at sea level; implying the intrinsic hypoxic adaptation still exists in the Tibetan high altitude natives.
