Increased vital and total lung capacities in Tibetan compared to Han residents of Lhasa (3,658 m)

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Abstract
Larger chest dimensions and lung volumes have been reported for Andean high‐altitude natives compared with sea‐level residents and implicated in raising lung diffusing capacity. Studies conducted in Nepal suggested that lifelong Himalayan residents did not have enlarged chest dimensions. To determine if high‐altitude Himalayans (Tibetans) had larger lung volumes than acclimatized newcomers (Han “Chinese”), we studied 38 Tibetan and 43 Han residents of Lhasa, Tibet Autonomous Region, China (elevation 3,658 m) matched for age, height, weight, and smoking history. The Tibetan compared with the Han subjects had a larger total lung capacity [6.80 ± 0.19 (mean ± SEM) vs 6.24 ± 0.18 1 BTPS, P < 0.05], vital capacity (5.00 ± 0.08 vs 4.51 ± 0.10 1 BTPS, P < 0.05), and tended to have a greater residual volume (1.86 ± 0.12 vs 1.56 ± 0.09 1 BTPS, P < 0.06). Chest circumference was greater in the Tibetan than the Han subjects (85 ± 1 vs 82 ± 1 cm, P < 0.05) and correlated with vital capacity in each group as well as in the two groups combined (r = 0.69, P < 0.05). Han who had migrated to high altitude as children (≤ 5 years old, n = 6) compared to Han adult migrants (≥ 18 years old, n = 26) were shorter but had similar lung volumes and capacities when normalized for body size. The Tibetans' vital capacity and total lung capacity in relation to body size were similar to values reported previously for lifelong residents of high altitude in South and North America. Thus, Tibetans, like North and South American high‐altitude residents, have larger lung volumes. This may be important for raising lung diffusing capacity and preserving arterial oxygen saturation during exercise.