Which of the following is a major environmental health risk associated with high-altitude flight?

• A. Hypoxia.
• B. Motion sickness.
• C. Noise exposure.
• D. Fatigue.

Answer: (A)

Hypoxia from reduced ambient oxygen pressure is the main environmental health risk at high altitude. As you ascend, barometric pressure drops, so even air with the same 21% oxygen has less oxygen available for your lungs to transfer into the blood. That lowers arterial oxygen content and the body’s tissues can’t receive enough oxygen quickly enough. The result is impaired judgment, slower reaction times, decreased coordination, and potentially loss of consciousness if not corrected with supplemental oxygen or cabin pressurization. Other issues like motion sickness, noise exposure, or fatigue can occur, but they don’t pose the rapid, system-wide threat that hypoxia does in flight.