Symptoms generally associated with mild to moderate altitude illness include:

·         Difficulty sleeping

·         Dizziness or light-headedness

·         Fatigue

·         Headache

·         Loss of appetite

·         Nausea or vomiting

·         Rapid pulse (heart rate)

·         Shortness of breath with exertion

Symptoms generally associated with more severe altitude illness include:

·         Bluish discoloration of the skin (cyanosis)

·         Chest tightness or congestion

·         Confusion

·         Cough

·         Coughing up blood

·         Decreased consciousness or withdrawal from social interaction

·         Gray or pale complexion

·         Inability to walk in a straight line, or to walk at all

·         Shortness of breath at rest

The rates of acute altitude sickness 3,000 m, 3,700 m, 3,900 m, 4,520 m and 5,300m above sea level are 40 percent, 57.3 percent, 63.8 percent, 89.24 percent and 100 percent, according to a survey Although these values are typical, experts point out that the human body is very adaptable and has a magical capability for acclimation. As breakthroughs have been made in determining the cause of altitude sickness and in the treatment, the cure rate of the two most common forms of acute altitude sickness -- high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE) -- has reached 99%.