Descending to a lower altitude is the most effective treatment for acute mountain sickness. Lower elevations provide higher oxygen pressure, allowing the body to recover from hypoxia and reverse symptoms such as headache, nausea, and fatigue. Even a modest descent of 500 to 1,000 meters (1,600 to 3,300 feet) can lead to rapid improvement. The sooner descent begins after recognizing worsening symptoms, the greater the chance of preventing severe complications like high-altitude cerebral or pulmonary edema. Rest and gradual acclimatization after descent help ensure full recovery and safer re-ascent if needed.