Cardiovascular adaptations in Andean natives after 6 wk of exposure to sea level.
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.
McKenzie
D C
DC
Department of Sport Science, Allan McGavin Sports Medicine Centre, University of British Columbia, Vancouver, Canada.
Goodman
L S
LS
Nath
C
C
Davidson
B
B
Matheson
G O
GO
Parkhouse
W S
WS
Hochachka
P W
PW
Allen
P S
PS
Stanley
C
C
Ammann
W
W
D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D000531:Altitude; D002302:Cardiac Output; D002320:Cardiovascular Physiological Phenomena; D006339:Heart Rate; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010568:Peru; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right