TABLE 1.
Physiological parameters studied in Sherpa and lowlanders at altitude.
| Parameter(s) |
Sherpa at high altitude |
Lowlander at altitude (meter) |
Reference(s) | ||||
| Sample size | Parameter value | Altitude | Sample size | Duration (days) | Parameter value | ||
| Heart rate while working at 900 kg⋅m/min-beats/min | 1 | 162 | 5,800 | 2 | 240 | 122 | Pugh, 1962; Pugh et al., 1964 |
| Lung diffusion capacity for oxygen-ml/min | 1 | 97 | 5,800 | 2 | 240 | 52.5 | Pugh, 1962 |
| Basal metabolic rate, kcal/m2 h | 3 | 46.1 ± 1.0 | 5,800 | 8 | 240 | 41.1 ± 3.6 | Gill and Pugh, 1964 |
| 10 different physiological parameters; measured, to test oxygen utilization at the cellular level | 4 | efficiently used O2 | 4,880 | 3 | 60 | less efficient to use O2 | Lahiri and Milledge, 1965 |
| Heart rate (while work rate at 1,265 kg-m/min)- beats/min | 4 | 198 | 4,880 | 2 | 63 | 146 | Lahiri et al., 1967 |
| Partial pressure of carbon dioxide in the arterial blood, mm Hg | 4 | 28.6 | 4,880 | 5 | 60 | 25.9 | Lahiri and Milledge, 1967 |
| Hemoglobin level in Tibetans living at 3658 m in Nepal; g/l00 ml | 52 | Male; 16.8 ± 1.4; Female: 14.5 ± 0.7 | – | Adams and Shresta, 1974 | |||
| Hemoglobin level in Tibetans living at 4000 m in Nepal; g/l00 ml | 51 | Male; 17.0 ± 1.25; Female:15.3 ± 0.8 | – | Adams and Strang, 1975 | |||
| Ratio of 2, 3 diphosphoglycerate and hemoglobin | 7 | 0.9 | 3,900 | 2 | 30 | 1.26 | Morpurgo et al., 1976 |
| Mean oxygen half saturation of hemoglobin | 7 | 27.3 ± 1.8 | 3,500 | 7 | 120 | 28.2 ± 1.3 | Samaja et al., 1979 |
| Arterial oxygen saturation (SaO2) | 10 | 88 ± 0.74 | 4,243 | 25 | 12 | 85.6 ± 1.0 | Hackett et al., 1980 |
| Body weight changes- Mean weight loss (kg) | 4 | constant | 5,400 | 13 | 25 | 1.9 to 4 | Boyer and Blume, 1984 |
| Hypoxic ventilatory response (HVR)-end-tidal PO2, 40 Torr | 6,300 | 9 | 25 | 21.2 ± 5.4 | Schoene et al., 1984 | ||
| Partial pressure of oxygen in arterial blood (Torr) | 6 | 34.5 ± 3.2 | 5,400 | 9 | – | 41.0 ± 3.3 | Santolaya et al., 1989 |
| Partial pressure of carbondioxide in arterial blood (Torr) | 6 | 27.5 ± 2.2 | 5,400 | 9 | – | 20.0 ± 2.8 | Sutton et al., 1988 |
| Hemoglobin oxygen affinity values | 14 | 29.8 ± 1.9 | – | 1 | – | 19 | Winslow et al., 1989 |
| Resting glucose appearance rate at sea level (1.79 ± 0.02) mg.kg−l.min-1 | – | – | 4,300 | 7 | 21 | 3.59 ± 0.08 | Brooks et al., 1991 |
| HVR shape parameter A, (mean ± SE) | 27 | 121 ± 17 | 3,658 | 30 | 9 ± 1 year | 81 ± 10 | Zhuang et al., 1993 |
| Resting mean pulmonary arterial pressure SE mmHg | 5 | 15 ± 1 | 22 | 28 ± 2 | Groves et al., 1993 | ||
| Glucose metabolic rates of myocardial regions | 6 | 0.32 ± 0.05 | 226 | 6 | 0.20 ±0 04 | Holden et al., 1995 | |
| Brain glucose metabolic rates | 6 | 0.71 | 6 | 19 | 0.73 | Hochachka et al., 1996b | |
| Signs of mild cortical atrophy | 7 | Seen in 1 | 21 | Seen in 13 | Garrido et al., 1996 | ||
| Partial pressure of carbon dioxide, mm Hg | 5 | 28.8 ± 1.2 | 3,400 | 4 | 40 | 22.0 ± 0.4 | Samaja et al., 1997 |
| Mean arterial blood pressure, mm Hg | 9 | 83 ± 6 | 4,243 | 10 | 7 | 94 ± 7 | Jansen et al., 2000 |
| Forced expiratory volume of adult male (%) | 146 | 110(107−114) | 3,840 | 103 | 103.8 (100.4-107.3) | Havryk et al., 2002 | |
| Heart Rate (beats min–1) means ± S.D. | 7 | 167 ± 10 | 5,050 | 10 | 28 | 149 ± 7 | Marconi et al., 2004 |
| Carried loads of their body weight (mean ± SD) | 96 | 93 ± 36% | 2,880 | 10 | 75% | Bastien et al., 2005a, b, 2016 | |
| Arterial oxygen saturation (SaO2) or (SpO2) | – | – | 5,620 | lower SaO2 in Han than Tibetans | Wu, 1990; Wu and Kayser, 2006 | ||
| Arterial oxygen saturation, % | 10 | 88 ± 3 | 40 | 10 | 97 ± 2 | Jansen et al., 2007 | |
| Statistically significant gender specific differences in SpO2 | Adult Tibetan female show higher SpO2 value than male | Weitz and Garruto, 2007 | |||||
| Serum angiotension-converling enzyme activity, IU/L/37°C | 105 | 14.5 ± 0.4 | 1,300 | 111 | 14.7 ± 0.4 | Droma et al., 2008 | |
| Mean arterial oxygen content at 8,400 m (26% lower than at 7100 m) | – | – | 8,400 | 4 | – | 145.8 ml per L | Grocott et al., 2009 |
| Muscle phosphocreatine recovery halftime- PCrtl/2 (s) | 7 | 22.2 ± 1.6 | 50 | 7 | – | 16.1 ± 1.1 | Edwards et al., 2010 |
| Radial arterial plasma NO2–(nmol I–1) | – | – | 4,559 | 26 | 4 | 263.6 ± 61.2 | Bailey et al., 2010 |
| Middle cerebral artery diameter [at 6,400 m = 6.66 mm] | – | – | 7,950 | 5 | 71 | 9.34 mm | Wilson et al., 2011 |
| Flow-mediated dilatation (FMD)-shear rate | 12 | 24490 ± 7230 | 5,050 | 12 | 14 | 14802 ± 5306 | Lewis et al., 2014 |
| Arterial oxygen saturation (mean ± SE) | 13 | 86 ± 1 | 5,050 | 13 | 9 | 83 ± 2 | Faoro et al., 2014 |
| Hemoglobin level ml. min(−l). mmHg(−l) | 13 | 61 ± 4 | 5,050 | 13 | 9 | 37 ± 2 | Faoro et al., 2014 |
| Lung diffusing capacities | 13 | 226 ± 18 | 5,050 | 13 | 9 | 153 ± 9 | Faoro et al., 2014 |
| Systolic pulmonary artery pressure | 95 | 29.4 ± 5.5 | 13 | 64 | – | 23.6 ± 4.8 | Bruno et al., 2014 |
| Left ventricular untwisting velocity, °/s | 11 | −93 ± 31 | 5,050 | 9 | 13 | −153 ± 38 | Stembridge et al., 2014 |
| Right ventricular isovolumic ralaxation time, ms | 11 | 64 ± 20 | 5,050 | 9 | 13 | 78 ± 14 | Stembridge et al., 2015 |
| No significant differences of dietary nitrate supplementation on AMS score | – | – | 4,559 | 28 | 7 | p = 0.29, p = 0.47 | Cumpstey et al., 2017 |
| Arterial oxygen saturation (%, 95% CI of Mean) | – | – | 5,300 | 11 | 13 | 73.0 (70.3–75.5) | Luks et al., 2017 |
| Relative PPARA mRNA expression of muscles tissues | 15 | 0.5158 | 5,300 | 10 | 19 | 1.0045 | Horscroft et al., 2017 |
| Post reproductive, Tibetan women (n=959)-Hemoglobin concentration, gm/dl | – | 13.8 | – | – | Cho et al., 2017 | ||
| Increase in nocturnal time course of blood oxygen saturation level at rest | – | – | 3,050 | 10 | 21 | 94.5% (91-97) | Tannheimer et al., 2017 |
| FMD unchanged (in rest and maximal exercise), at low and high altitude | – | – | 3,800 | 9 | 7 | (6.3 ± 1.3)% | Tymko et al., 2017a |
| Brachial artery blood flow [at Sea level- (142.7 ± 30.6)], ml/min | – | – | 5,050 | 14 | 21 | 53.1 ± 11.1 | Tymko et al., 2017b |
| Number of circulating microparticles in blood (CD 66b+)/μ1 (21 ± 4) Sea level | – | 3,800 | 10 | 3 | 74 ± 17 | Tremblay et al., 2017 | |
| Birth-weight (kg) in Tibetans & Han; at 3,000–4,000 m altitude | 100 | 3.14 (3.06, 3.22) | <4,000 | 100 | 2.61 (2.34, 2.88) | Moore et al., 2001 | |
| Case report of a 32 week gestation Sherpa at 5160 m and her data after 10 month postpartum | No apparent maternal, fetal or neonatal complications | – | Davenport et al., 2018 | ||||
| Arterial oxygen pressure (PaO2; mm Hg) | – | – | 4,100 | 8 | 50 | 54 ±1.2 | Lundby et al., 2018 |
| Prefatigue, maximal voluntary contraction torque, N. m | 9 | 50.1 ± 11.3 | 5,050 | 9 | – | – | Ruggiero and Mcneil, 2018 |
| Maximal voluntary contractile force (kg) | 10 | 44.3 ± 14.1 | 5,050 | 12 | 10 | 58.2 ± 8.1 | Ruggiero et al., 2018 |
| Brachial artery flow-mediated dilation (FMD) | 12 | 5.8 ± 2.8% | 5,050 | 22 | 10 | 3.8 ± 2.8% | Tremblay et al., 2018 |
| Resting posterior cerebral artery velocity | – | – | 4.240 | 10 | 13 | 43 cm/s | Leacy et al., 2018 |
| Lowland origin; Female SpO2; Mean (SD), (%)[95.2 (1.2); at 600 m] | – | – | 3,500 | 20 | 1 | 76.7 (5.6) | Burtscher et al., 2018 |
| Partial pressure of arterial carbon dioxide. mmHg | 11 | 32.1 ±2.5 | 5,050 | 21 | 21 | 30.0 ±1.9 | Willie et al., 2018 |
| Peripheral oxygen saturation in female [at 600 m; 96.9 (1.0)] Mean (SD) % | – | – | 3,840 | 20 | 1 | 86.5 (6.5) | Burtscher et al., 2019 |
| SpO2 (%) [at Sea Level (244 m) is 98 ± 1] | – | – | 3.800 | 12 | 10 | 89.1 ± 3 | Stembridge et al., 2019 |
| Free cysteine and plasma total free thiol concentrations | – | – | 4,559 | 4 | Elevated at 4,559 m than at 50 m | Cumpstey et al., 2019 | |
| Sublingual capillary total vessel density [at Sea Level; 18.81 ± 3.92 mm mm–2 | – | – | 7,042 | 10 | 21 | 21.25 ±2.27 | Hilty et al., 2019 |
| Sympathetic nerve activity, burst frequency (bursts min–1) | 8 | 22 ± 11 | 5,050 | 14 | 20 | 30 ± 9 | Simpson et al., 2019 |