What is hypoxia?
Hypoxia is a well-known flight safety hazard when flying at high altitude. A loss of cabin pressure with a decreased oxygen content in the air will cause hypoxia. Hypoxia is insidious and creeping and causes incapacitation due to lack of oxygen in the body. The reaction is individual and the symptoms differ. Learning to recognize your own personal symptoms is crucial.
Common symptoms
- Tachycardia
- Air hunger
- Lightheadedness
- Euphoria
- Warmth and cold feeling
- Tingling sensations
- Vertigo
- Visual impairment
Common observed signs
- Rapid and deep breathing
- Cyanosis of fingers and lips
- Slow reaction time
- Bad judgement
Make the most out of your time
On normal flight altitudes hypoxia quickly cause medical incapacitation with inability to perform the right actions. TUC, Time of Useful Consciousness, is the time you have to perform the right maneuvers before you get even more affected of hypoxia or unconscious. If you are performing any physical activity the time declines further as you can see in the table.
Altitude |
Time of Useful ConsciousnessTUC |
|---|---|
| 20,000 feet / 6,000 m MSL | 10 – 30 minutes |
| 22,000 feet / 6,500 m MSL | 5 – 10 minutes |
| 25,000 feet / 7,500 m MSL | 3 – 5 minutes |
| 28,000 feet / 8,500 m MSL | 2,5 – 3 minutes |
| 30,000 feet / 9,000 m MSL | 1 – 2 minutes |
| 35,000 feet / 10,500 m MSL | 30 – 60 seconds |
| 40,000 feet / 12,000 m MSL | 15 – 20 seconds |
| 45,000 feet / 13,500 m MSL | 9 – 15 seconds |