两个地方有疑惑，理解的对吗？谢谢

Altitude Decompression Sickness

Flying at high altitude in military aircraft exposes pilots to significant degrees of decompression; a cabin altitude of 9000 m (30 000 ft) is equivalent to approximately 0.3 ATA.During actual flights, symptoms of decompression sickness tend to be underreported because these elite pilots may fear restrictions on their flying activities. However, during their careers, three-quarters of pilots experience problems, and almost 40% of trainee pilots develop symptoms during hypobaric chamber testing to normal cabin altitudes.1Joint pain is predictably the most common symptom, whereas the ‘chokes’ (substernal pain, cough and dyspnoea) occur in 1% to 3% of cases. Breathing 100% oxygen for 60 minutes before altitude exposure significantly attenuates the symptoms seen, and is required by the US Air Force before flying.

高空减压病^19,20

军用飞机在高空飞行时，飞行员处于压力明显降低的环境，9000m（30000英尺）高度的机舱压力相当于约0.3个ATA。在实际飞行中，精英飞行员为了避免影响职业生涯，往往减少了减压病症状的报告。然而，3/4的飞行员在其职业生涯中曾经有过减压病症状，近40%的见习飞行员在正常高度的低压舱测试中出现减压病症状¹⁹。关节疼痛最常见，而1%～3%的病例中发生“窒息”（胸骨后疼痛、咳嗽和呼吸困难）。在高空飞行前，吸纯氧60min可显著减轻以上症状，这也是美国空军飞行前的要求。

老师，两个地方有疑惑，理解的对吗？谢谢