Premium
Superior exercise performance in lifelong Tibetan residents of 4,400 m compared with Tibetan residents of 3,658 m
Author(s) -
Curran Linda S.,
Zhuang Jianguo,
Droma Tarshi,
Moore Lorna G.
Publication year - 1998
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/(sici)1096-8644(199801)105:1<21::aid-ajpa3>3.0.co;2-g
Subject(s) - effects of high altitude on humans , altitude (triangle) , vo2 max , hypoxia (environmental) , population , aerobic capacity , oxygen , heart rate , medicine , zoology , chemistry , mathematics , biology , anatomy , blood pressure , geometry , environmental health , organic chemistry
Few environments challenge human populations more than high altitude, since the accompanying low oxygen pressures (hypoxia) are pervasive and impervious to cultural modification. Work capacity is an important factor in a population's ability to thrive in such an environment. The performance of work or exercise is a measure of the integrated functioning of the O 2 transport system, with maximal O 2 uptake (VO 2 max) a convenient index of that function. Hypoxia limits the ability to transport oxygen: maximal O 2 uptake decreases with ascent to high altitude, and years of high altitude residence do not restore sea level VO 2 maxvalues. Since Tibetans live and work at some of the highest altitudes in the world, their ability to exercise at very high altitude (<4,000 m) may define the limits of human adaptation to hypoxia. We transported 20 Tibetan lifelong residents of ≥4,400 m down to 3,658 m in order to compare them with 16 previously studied Tibetan residents of Lhasa (3,658 m). The two groups of Tibetans were matched for age, weight, and height. All studies were performed in Lhasa within 3 days of the 4,400 m Tibetans' arrival. Standard test protocol and criteria were used for attaining VO 2 maxon a Monark bicycle ergometer, while measuring oxygen uptake (VO 2 , ml/kg − min STPD), heart rate (bpm), minute ventilation (VE, 1/min BTPS), and arterial oxygen saturation (Sa O 2, %). The 4,400 m compared with 3,658 m residents had, at maximal effort, similar VO 2 (48.5 ± 1.2 vs. 51.2 ± 1.4 ml/kg − min, P = NS), higher workload attained (211 ± 6 vs. 177 ± 7 watts, P < 0.01), lower heart rate (176 ± 2 vs. 191 ± 2 bpm, P < 0.01), lower ventilation (127 ± 5 vs. 149 ± 5 l/min BTPS, P < 0.01), and similar Sa O 2(81.9 ± 1.0 vs. 83.7 ± 1.2%, P = NS). Furthermore, over the range of submaximal workloads, 4,400 m compared with 3,658 m Tibetans had lower VO 2 ( P < 0.01), lower heart rates ( P < 0.01), and lower ventilation ( P < 0.01) and Sa O 2( P < 0.05). We conclude that Tibetans living at 4,400 m compared with those residing at 3,658 m achieve greater work performance for a given VO 2 at submaximal and maximal workloads with less cardiorespiratory effort. Am J Phys Anthropol 105:21–31, 1998. © 1998 Wiley‐Liss, Inc.