Comparisons of oxygen transport between Tibetan and Han residents at moderate altitude

To compare the difference for oxygen transport between Tibetans living for generations at high altitude and acclimatized Han newcomers to high altitude, we measured the ventilatory, circulatory, metabolic, and gas exchange functions during exercise in 17 Tibetans and 19 Hans at the altitude of 3417 m. At maximal effort, the Tibetans, compared with the Hans, showed higher O 2 consumption ( V ˙ o 2 max ) (2.54±0.1 versus 2.10±0.1 liters min −1 , p p −1 , p P −1 ) was higher than that in the Hans (68.0±3.9 liters min −1 ), but the ventilatory equivalent was equal. The anaerobic threshold for absolute O 2 consumption ( V ˙ o 2 AT ) for the Tibetans and Hans was 1.91±0.1 versus 1.45±0.1 liters min −1 , respectively ( p 2 consumption (in % V ˙ o 2 max ) was 76.2±1.5 versus 70.5±2.2, respectively ( p V ˙ o 2 max correlated well with maximal cardiac output. No difference was found in the maximal heart rate between the two groups. Arterial oxygen desaturation from rest to exercise in the Hans (15.3%; 90.3–76.5%) was greater than that in the Tibetans (9.2%; 90.1–81.8%). We conclude that the lifelong exposure to an hypoxic environment has resulted in an increase in oxygen transport and improved aerobic exercise performance.