title: 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.
authors.affiliation: Department of Sport Science, Allan McGavin Sports Medicine Centre, University of British Columbia, Vancouver, Canada.
authors.forename: D C
authors.initials: DC
authors.lastname: McKenzie
authors.forename: L S
authors.initials: LS
authors.lastname: Goodman
authors.forename: C
authors.initials: C
authors.lastname: Nath
authors.forename: B
authors.initials: B
authors.lastname: Davidson
authors.forename: G O
authors.initials: GO
authors.lastname: Matheson
authors.forename: W S
authors.initials: WS
authors.lastname: Parkhouse
authors.forename: P W
authors.initials: PW
authors.lastname: Hochachka
authors.forename: P S
authors.initials: PS
authors.lastname: Allen
authors.forename: C
authors.initials: C
authors.lastname: Stanley
authors.forename: W
authors.initials: W
authors.lastname: Ammann
mesh_terms: 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