Exercise pathophysiology in patients with chronic mountain sickness exercise in chronic mountain sickness.
BACKGROUND
Chronic mountain sickness (CMS) is characterized by a combination of excessive erythrocytosis,severe hypoxemia, and pulmonary hypertension, all of which affect exercise capacity.


METHODS
Thirteen patients with CMS and 15 healthy highlander and 15 newcomer lowlander control subjects were investigated at an altitude of 4,350 m (Cerro de Pasco, Peru). All of them underwent measurements of diffusing capacity of lung for nitric oxide and carbon monoxide at rest, echocardiography for estimation of mean pulmonary arterial pressure and cardiac output at rest and at exercise, and an incremental cycle ergometer cardiopulmonary exercise test.


RESULTS
The patients with CMS, the healthy highlanders, and the newcomer lowlanders reached a similar maximal oxygen uptake at 32 1, 32 2, and 33 2 mL/min/kg, respectively, mean SE( P 5 .8), with ventilatory equivalents for C O 2 vs end-tidal P CO 2 , measured at the anaerobic threshold,of 0.9 0.1, 1.2 0.1, and 1.4 0.1 mm Hg, respectively ( P , .001); arterial oxygen content of 26 1, 21 2, and 16 1 mL/dL, respectively ( P , .001); diffusing capacity for carbon monoxide corrected for alveolar volume of 155% 4%, 150% 5%, and 120% 3% predicted, respectively( P , .001), with diffusing capacity for nitric oxide and carbon monoxide ratios of 4.7 0.1 at sea level decreased to 3.6 0.1, 3.7 0.1, and 3.9 0.1, respectively ( P , .05) and a maximal exercise mean pulmonary arterial pressure at 56 4, 42 3, and 31 2 mm Hg, respectively ( P , .001).


CONCLUSIONS
The aerobic exercise capacity of patients with CMS is preserved in spite of severe pulmonary hypertension and relative hypoventilation, probably by a combination of increased oxygen carrying capacity of the blood and lung diffusion, the latter being predominantly due to an increased capillary blood volume.
Department of Pulmonology, VU University Medical Center, Amsterdam, The Netherlands.
Herman
H
Groepenhoff
Department of Pulmonology, VU University Medical Center, Amsterdam, The Netherlands.
Marieke J
MJ
Overbeek
Department of Cardiology, University of Catania, Catania, Italy.
Massimiliano
M
Mulè
Department of Respiratory Medicine, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
Mart
M
van der Plas
Department of Cardiology, Monaldi Hospital, Second University of Naples, Naples, Italy.
Paola
P
Argiento
Department of Medicine and High Altitude Research Institute, Universidad Peruana Cayetano Heredia, Lima, Peru.
Francisco C
FC
Villafuerte
Department of Pathophysiology, Faculty of Medicine, Free University of Brussels, Brussels, Belgium.
Sophia
S
Beloka
Department of Pathophysiology, Faculty of Medicine, Free University of Brussels, Brussels, Belgium.
Vitalie
V
Faoro
Department of Medicine and High Altitude Research Institute, Universidad Peruana Cayetano Heredia, Lima, Peru.
Jose L
JL
Macarlupu
Department of Physiology, University Hospital Bordeaux, Bordeaux, France.
Herve
H
Guenard
Laboratory of Physiologic Adaptations to Physical Activities, Poitiers University, Poitiers, France.
Claire
C
de Bisschop
Department of Pneumology, St Elisabeth Hospital, Namur, Belgium.
Jean-Benoit
JB
Martinot
Department of Pathophysiology, Faculty of Medicine, Free University of Brussels, Brussels, Belgium.
Rebecca
R
Vanderpool
Department of Medicine and High Altitude Research Institute, Universidad Peruana Cayetano Heredia, Lima, Peru.
Dante
D
Penaloza
Department of Pathophysiology, Faculty of Medicine, Free University of Brussels, Brussels, Belgium. Electronic address: rnaeije@ulb.ac.be.
Robert
R
Naeije
D000531:Altitude; D000532:Altitude Sickness / Q000175:diagnosis / Q000503:physiopathology*; D062186:Arterial Pressure / Q000502:physiology*; D002908:Chronic Disease; D025401:Echocardiography, Stress; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D006801:Humans; D010568:Peru; D011379:Prognosis; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D014195:Travel