Journal of Applied Physiology, Vol 70, Issue 6 2650-2655, Copyright © 1991 by American Physiological Society
Cardiovascular adaptations in Andean natives after 6 wk of exposure to sea level
D. C. McKenzie, L. S. Goodman, C. Nath, B. Davidson, G. O. Matheson, W. S. Parkhouse, P. W. Hochachka, P. S. Allen, C. Stanley and W. Ammann
Department of Sport Science, Allan McGavin Sports Medicine Centre, University of British Columbia, Vancouver, Canada.
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.
