Early signs of acute mountain sickness and recommended action.

• A. Headache, nausea, fatigue, insomnia; descend if symptoms worsen; rest; hydration; oxygen if available; avoid further ascent.
• B. Cough, fever, rash; increase altitude gradually.
• C. Joint pain and swelling; immobilize.
• D. Skin numbness; apply local heat.

Answer: (A)

Recognizing early signs of acute mountain sickness and knowing how to respond is the key idea. The early signs—headache, nausea, fatigue, and insomnia—reflect the body's struggle to acclimate to higher altitude. If these symptoms appear, the best course is to slow or stop ascending and prioritize acclimatization: rest, stay hydrated, and give the body time to adjust. If symptoms worsen, descend to lower elevation to relieve pressure and prevent progression to more serious illness. Oxygen can help if available, and avoid further ascent until symptoms resolve. The other descriptions describe conditions not related to altitude illness, so they don’t fit the appropriate response.