Hypoxia occurs when there is insufficient oxygen; which action directly mitigates hypoxia by increasing available oxygen?

• A. Use supplemental oxygen
• B. Descend to a lower altitude
• C. Increase airspeed
• D. Open a cabin window

Answer: (A)

Hypoxia happens when the body doesn’t get enough oxygen, usually because the air at altitude has a lower partial pressure of oxygen. The direct way to fix this is to increase how much oxygen you’re breathing. Supplemental oxygen raises the fraction of inspired oxygen, which raises the alveolar and arterial oxygen levels, improving oxygen delivery to tissues regardless of how high you are.

Descending to a lower altitude would help by increasing ambient oxygen, but it’s a secondary fix and may not be feasible immediately; providing oxygen directly increases the amount of oxygen available to the body right away. Opening a cabin window is unsafe at altitude, and increasing airspeed does not change the amount of oxygen you breathe.