Altitue sickness, also known as acute mountain sickness (AMS), altitude illness, or soroche, is a pathological condition that is caused by acute exposure to low air pressure (usually outdoors at high altitudes). It commonly occurs above 2,400 metres (approximately 8,000 feet). Acute mountain sickness can progress to high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE).