Cardiorespiratory fitness and effects of ubiquinol during high-altitude acclimatization and deacclimatization: The SCARF trial.

The dynamic characteristics of cardiorespiratory fitness during high-altitude acclimatization and deacclimatization are not well elucidated, and whether ubiquinol exerts beneficial effects on cardiorespiratory fitness remains debated. In this trial, 41 volunteers were randomized to receive oral ubiquinol or placebo administration, 14 days before departure to highlands. All individuals were carried to 3900 m by air and then returned to 300 m after 7 days. Cardiopulmonary exercise testing was performed at baseline, on the third day after arrival in the highlands, and on the seventh day after return. This trial revealed the dynamic characteristics of cardiorespiratory fitness during the entire high-altitude acclimatization and deacclimatization process. The short-term journey to the highlands did not significantly affect cardiorespiratory fitness or physical performance capacity after the return. Cardiovascular and respiratory recoveries were desynchronized after returning from the highlands. Ubiquinol supplementation maintained the physical performance capacity in the highlands and facilitated acclimatization to hypoxia. Trial registration: The Chinese Clinical Trial Registry, ChiCTR2200059900, http://www.chictr.org.cn/ChiCTR2200059900.