What is high altitude sickness?
High altitude sickness, also called mountain sickness, is a problem that occurs when people travel from lower elevations to about 8,000 feet or more above sea level. Serious types of altitude sickness include high-altitude pulmonary edema (fluid in the lungs) and high-altitude cerebral edema (swelling of the brain). With altitude sickness, the travelers may first feel like having the flu or a hangover, with symptoms such as, headache, fatigue, appetite loss, nausea, insomnia and difficulty breathing during exercise.
