Zhou et al. [24] investigated the ventilatory functions in 113 newly recruited soldiers at sea level, and then the soldiers were transferred to 3658 m by airplane. Two and three days after ascending to high altitude, the investigators scored the symptoms of acute mountain sickness and evaluated the relationship between ventilatory functions and symptom scores. They found that FVC, peak expiratory flow, and forced expiratory volume in 1 second in soldiers with HAPE were significantly lower than those in soldiers without HAPE. Thus, they speculated that ventilatory functions at sea level could be used to screen subjects susceptible to HAPE. [25] investigated whether a cardiopulmonary exercise test could be used to predict HAPE. They found that subjects with poor cardiac and ventilatory responses to hypoxia were more susceptible to HAPE. They assessed several parameters, including the heart rate to oxygen saturation ratio (ΔHR/ΔSaO 2 ) and the minute ventilation to oxygen saturation ratio (ΔVE/ΔSaO 2 ), to establish a mathematical model that could predict HAPE.