AMS · acute mountain sickness
After gaining altitude, headache together with nausea, dizziness or unusual fatigue can suggest AMS. Stop ascending and tell the guide. Do not sleep higher while symptoms persist. If symptoms worsen or do not improve, descend and seek medical assessment.
HAPE · high-altitude pulmonary edema
Breathlessness at rest, an unusual loss of exercise capacity, cough or chest tightness can indicate a serious lung problem. Symptoms may progress to marked difficulty breathing, bluish lips or frothy sputum. Do not wait for every sign: stop ascent, arrange descent or evacuation and seek urgent medical attention.
HACE · high-altitude cerebral edema
Confusion, unusual behavior, severe drowsiness or inability to walk steadily at altitude are emergency warning signs. HACE can be life-threatening. Arrange immediate assisted descent or evacuation and urgent medical help; never send an affected person downhill alone.
Acclimatization and medical planning
Gain altitude gradually, allow rest and plan flexibility. A previous summit or a few days in a city does not guarantee acclimatization. Seek individualized medical advice for existing conditions, medications, pregnancy or a history of altitude illness. Avoid alcohol and sedating medicines at altitude unless your clinician advises otherwise; drink normally rather than forcing excessive water.
Oxygen, if available and appropriately used, may support treatment but does not replace descent or urgent medical care. Pulse oximetry readings do not replace symptoms and clinical judgment. This is general education, not a diagnosis, fitness clearance or a claim that oxygen is carried on our trips.