Name two common early signs of hypoxia in the cabin.

• A. Headache and dizziness
• B. Nausea and vomiting
• C. Cough and throat irritation
• D. Visual disturbances and ringing in ears

Answer: (B)

Oxygen levels in the brain drop first, so the body's early warning signs are neurological. A headache and feeling dizzy or lightheaded are classic early indicators of cabin hypoxia because brain tissue is the first to suffer from reduced oxygen. Recognizing these symptoms promptly is crucial—they signal you should use supplemental oxygen and/or descend to a lower cabin altitude.

Nausea and vomiting aren’t typical early signs of hypoxia; they’re more often caused by motion sickness, dehydration, or other factors and tend to appear after the initial brain-oxygen deficit. Cough and throat irritation point to airway irritation or infection, not the initial oxygen shortage. Visual disturbances and ringing in the ears can occur with hypoxia but are less common early signs and may indicate more advanced hypoxia or other conditions.