Definition
A condition in which the body's tissues receive no oxygen, or so little oxygen that normal cellular function cannot continue. In aviation, anoxia most commonly refers to the severe oxygen starvation that occurs at high altitudes when supplemental oxygen is not used.
Plain English
The body, especially the brain, is being starved of oxygen. Without enough oxygen, the pilot cannot think clearly, stay conscious, or fly the aircraft safely.
Context Anchor
Encountered in aviation physiology, high-altitude flight, oxygen system discussions, and training about the effects of reduced oxygen on pilots and passengers.
Derivation
From Greek 'an-' meaning 'without' and 'oxia' from 'oxygen.' Literally 'without oxygen.' Knowing this helps separate it from hypoxia, which means 'reduced oxygen' rather than 'no oxygen.'
Why Pilots Care
Leads to rapid loss of consciousness and control if not recognized during unpressurized flight above 10,000 feet.
Grounding Statement
At altitude, the air may not provide enough usable oxygen for the body, and the brain is usually one of the first places where the effects show up.
Intuition Check
Do not treat anoxia as just feeling short of breath. A person can be losing usable oxygen and still not feel obvious air hunger at first.
Example Sentence 1
The flight surgeon explained that anoxia can occur within seconds after a rapid decompression at high altitude.
Example Sentence 2
The preflight briefing covered how anoxia develops faster than most pilots expect in a depressurized cabin.