Zhang et al. [19] used submaximal bench stepping to directly calculate maximal oxygen uptake (VO 2max ), which was then applied to predict HAPE. They conducted this study in soldiers ascending to high altitude. They found that soldiers with a VO 2max ≥ 3 L/min at sea level were less likely to develop HAPE than those with a VO 2max < 3 L/min. [20] measured FVC, body surface area, and thoracic volume in an effort to predict HAPE in individuals ascending to high altitude. They found that a FVC/body surface area <3 L/m 3 , FVC/thoracic volume <400 L/m 3 , lung/body index >30, and lung/thorax index >0.24 were associated with increased risk for HAPE.