High Altitude Pulmonary Edema (HAPE) is a serious condition that can occur when individuals ascend to high altitudes, typically above 8,000 feet (2,400 meters). It results from the body’s inability to adapt to lower oxygen levels, leading to fluid accumulation in the lungs. Symptoms include shortness of breath, cough, fatigue, and chest tightness. HAPE can develop rapidly, often within a few days of reaching high altitude. It is more common in individuals who ascend too quickly without proper acclimatization. Immediate descent to a lower altitude and medical treatment are essential for recovery.