Cardiovascular adaptations in Andean natives after 6 wk of exposure to sea level

Abstract

Six male Quechua Indians (34.0 +/- 1.1 yr, 159.5 +/- 2.1 cm, 60.5 +/- 1.6 kg), life-long residents of La Raya, Peru (4,350-m altitude with an average barometric pressure of 460 Torr), were studied using noninvasive methods to determine the structural and functional changes in the cardiovascular system in response to a 6-wk deacclimation period at sea level. Cardiac output, stroke volume, and left ventricular ejection fractions were determined using radionuclide angiographic techniques at rest and during exercise on a cycle ergometer at 40, 60, and 90% of a previously determined maximal O2 consumption. Subjects at rest were subjected to two-dimensional and M-mode echocardiograms and a standard 12-lead electrocardiogram. Hemoglobin and hematocrit were measured on arrival at sea level by use of a Coulter Stacker S+ analyzer. After a 6-wk deacclimation period, all variables were remeasured using the identical methodology. Hemoglobin values decreased significantly over the deacclimation period (15.7 +/- 1.1 to 13.5 +/- 1.2 g/dl; P less than 0.01). The results indicate that the removal of these high-altitude-adapted natives from 4,300 m to sea level for 6 wk results in only minor changes to the cardiac structure and function as measured by these noninvasive techniques.

Structural Modulation of Brain Development by Oxygen: Evidence on Adolescents Migrating from High Altitude to Sea Level Environment

“…HA residents who descended to SL over a three-month period showed a slow disappearance of electrocardiographic signs of right ventricular hypertrophy [30]. The hemoglobin in HA natives was significantly reduced during the 6 weeks at SL [42]. Increased vital capacity was found in healthy male HA residents in the third day after their arrival at SL [41].…”

“…HA natives have developed adaptations in respiratory and cardiovascular function [38]–[40]. After residing at SL for a long period of time, they redeveloped an adaption to high concentration of oxygen environment [29]–[32], [41], [42]. In the present study, pulmonary function and cardiovascular function were also examined.…”

Cortical Thickness of Native Tibetans in the Qinghai-Tibetan Plateau

“…For example, when HA adult natives descended to sea level for several weeks, their cardiac functions remained unchanged. 79,80 Third, the interethnic difference of brain structure can be large. Brain morphologic differences between populations of different origins have been found in whole-brain and region-specific volume.…”

31P magnetic resonance spectroscopy of the Sherpa heart: a phosphocreatine/adenosine triphosphate signature of metabolic defense against hypobaric hypoxia.

“…Earlier physiological studies have shown that cardiac output in high-altitude natives is adjusted according to the acclimation state (6) and especially according to the 02-carrying capacity of the blood. Earlier biochemical studies of the metabolic properties of the heart in hypoxia-adapted natives found evidence for elevated glucose preference of the heart (7,8).…”