Normoxic ventilatory response in lowlander and Sherpa elite climbers

Abstract

The differences in ventilatory response to exercise of some highland ethnic communities is a controversial issue. We have evaluated the differences in ventilatory response to exercise at sea level between two groups of elite climbers, four Himalayan Sherpas (S) and four Caucasian lowlanders (C), after descent from extreme altitude. All of them performed a progressive-intensity exercise test on a treadmill under normoxic conditions. Pulmonary gas exchange was obtained until exhaustion by means of an automatic gas-analyzer system. Significant differences in expired ventilation and carbon dioxide production were found between the two groups, the V ̇ e · V ̇ O 2 −1 being lower in the S at rest (41.9±5) in comparison with C (48.7±9) ( P<0.05), higher at medium loads of the test (S=28.2±4 vs. C=25.7±2; P<0.05) and reaching similar values at higher loads (S=34.5±2 vs. C=35.6±4; NS). We conclude that the special ventilatory response observed in these highlanders could explain their adaptation to altitude, allowing higher oxygen blood saturation at medium working loads and reducing the risk of neurological injury caused by a high ventilatory response when exercising at high intensity effort under extreme altitude environment.