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Human Performance

2.3.4.3 Symptoms of oxygen deficiency

What symptoms should you be aware of when it comes to oxygen deficiency?

Symptoms of Oxygen deficiency

Observed Self-experienced

Mental Elevated mood Confusion
Poor performance Elevated mood

Poor judgment Good performance

Physical Increased breathing rate Dizziness
Poor coordination Nausea

Unconsciousness Headache
Ringing in ears

Other Aggressive behavior Blurred vision

Faded colors
Tunnel vision

Tingling in arms and fingers
Blue lips and fingers

Oxygen deficiency can cause unconsciousness and death.

2.3.4.4 Time of useful consciousness

There is a concept called Time of Useful
Relationship Between
Consciousness (TUC). Altitude and TUC

This refers to the time during which a Altitude (feet) TUC

person remains capable of taking 50.000 9 – 12 sek

purposeful action in an oxygen-deficient 43.000 9 – 12 sek
40.000 15 – 20 sek
environment.
35.000 30 – 60 sek
30.000 1 – 2 min

28.000 2,5 – 3 min
This table shows the relationship between
25.000 4 – 6 min
altitude and TUC. 22.000 8 – 10 min
18.000 20 – 30 min

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 142