[Hypoxia in aviation: list of possible causes].

Hypoxia represents a major physiological challenge in aviation, often underestimated due to its subtle onset and individually variable symptoms. This article summarizes the physical basis of decreasing oxygen partial pressure with altitude and its impact on human performance. Even at moderate altitudes (2500-4000 m), cognitive functions, reaction times, and visual performance decline significantly-often without the affected person noticing. At higher altitudes, time of useful consciousness rapidly decreases, especially in cases of sudden decompression. Although the body initiates compensatory mechanisms, such as hyperventilation and increased heart rate, these are limited and can lead to secondary complications. The key threat lies in the mismatch between actual impairment and perceived capability. Understanding hypoxia's mechanisms, recognizing early signs, and using oxygen systems correctly are critical to maintaining flight safety across all aviation sectors.