Exercise Performance in Central Asian Highlanders: A Cross-Sectional Study

Forrer, Aglaia, Philipp M. Scheiwiller, Maamed Mademilov, Mona Lichtblau, Ulan Sheraliev, Nuriddin H. Marazhapov, Stéphanie Saxer, Patrick Bader, Paula Appenzeller, Shoira Aydaralieva, Aybermet Muratbekova, Talant M. Sooronbaev, Silvia Ulrich, Konrad E. Bloch, and Michael Furian. Exercise performance in central Asian highlanders: A cross-sectional study. High Alt Med Biol. 22:386-394, 2021. Life-long exposure to hypobaric hypoxia induces physiologic adaptations in highlanders that may modify exercise performance; however, reference data for altitude populations are scant. Life-long residents of the Tien Shan mountain range, 2,500 - 3,500 m, Kyrgyzstan, free of cardiopulmonary disease, underwent cardiopulmonary cycle exercise tests with a progressive ramp protocol to exhaustion at 3,250 m. ECG, breath-by-breath pulmonary gas exchange, and oxygen saturation by pulse oximetry (SpO₂) were measured. Among 81 highlanders, age (mean ± SD) 48 ± 10 years, 46% women, SpO₂ at rest was 88% ± 2%, peak oxygen uptake (V'O₂peak) was 21.6 ± 5.9 mL/kg/min (76% ± 15% predicted for a low-altitude reference population); peak work rate (Wpeak) was 117 ± 37 W (77% ± 17% predicted), SpO₂ at peak was 84% ± 5%, heart rate reserve (220 - age - maximal heart rate) was 28 ± 17/min, ventilatory reserve (maximal voluntary ventilation - maximal minute ventilation) was 68 ± 32 l/min, and respiratory exchange ratio was 1.03 ± 0.09. Peak BORG-CR10 dyspnea and leg fatigue scores were 5.1 ± 2.0 and 6.3 ± 2.1. In multivariable linear regression analyses, age and sex were robust determinants of Wpeak, V'O₂peak, and metabolic equivalent (MET) at peak, whereas body mass index, resting systolic blood pressure, and mean pulmonary artery pressure were not. The current study shows that V'O₂peak and Wpeak of highlanders studied at 3,250 m, near their altitude of residence, were reduced by about one quarter compared with mean predicted values for lowlanders. The provided prediction models for V'O₂peak, Wpeak, and METs in central Asian highlanders might be valuable for comparisons with other high altitude populations.