Basic information description Altitude illness results from travel to higher-than-normal altitudes. It can affect anyone, no matter what his or her age or how healthy they are. Types of altitude illness include: Acute mountain sickness (AMS); the most common. High-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE). These are less common. frequent signs and symptoms Mild symptoms may begin when you climb or travel to around 7000 to 8000 feet. Headache,...