Risk assessment for acute altitude illness
| Planned ascent profile and prior history at high altitude# | |
| Low risk | Ascent ≤500 m·day−1 above 2500 m Ascent >500 m·day−1 above 2500 m in persons with exposure to high altitude <3000 m in preceding weeks No history of AMS, HACE or HAPE with similar ascent profile |
| Moderate risk | Unknown susceptibility to AMS, HACE or HAPE and planned ascent >500 m·day−1 above 3000 m Unknown susceptibility to acute altitude illness and planned ascent to >3000 m in 1 day |
| High risk | Unknown susceptibility to AMS, HACE or HAPE and planned very rapid ascent (>>500 m·day−1) to final altitude >4000 m History of AMS, HACE and HAPE with previous exposure similar to the planned ascent |
AMS: acute mountain sickness; HACE: high-altitude cerebral oedema; HAPE: high-altitude pulmonary oedema. #: altitudes refer to the individual's sleeping elevation.