Forrer A; Scheiwiller PM; Mademilov M; Lichtblau M; Marazhapov NH; Saxer S; Bader P; Appenzeller P;
Aydaralieva S; Muratbekova A; Sooronbaev TM; Ulrich S; Bloch KE; Furian M;
High altitude medicine & biology [High Alt Med Biol] 2021 Aug 24. Date of Electronic Publication: 2021 Aug 24.
Introduction: Life-long exposure to hypobaric hypoxia induces physiologic adaptations in highlanders that may modify exercise performance; however, reference data for altitude populations are scant.
Methods: 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 (SpO 2 ) were measured.
Results: Among 81 highlanders, age (mean ± SD) 48 ± 10 years, 46% women, SpO 2 at rest was 88% ± 2%, peak oxygen uptake (V’O 2 peak) 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), SpO 2 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’O 2 peak, and metabolic equivalent (MET) at peak, whereas body mass index, resting systolic blood pressure, and mean pulmonary artery pressure were not.
Conclusions: The current study shows that V’O 2 peak 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’O 2 peak, Wpeak, and METs in central Asian highlanders might be valuable for comparisons with other high altitude populations.