When a person travels to a location that is greater than 8,000 feet, they must do so at a speed that allows their body to acclimatize to certain changes, such as decreased air pressure, low humidity, and greater exposure to ultraviolet rays. Typically, full acclimatization can take as much as five days. If a person does not fully acclimatize to the higher altitude, it may cause a condition known as altitude sickness. The three forms of altitude sickness are acute mountain sickness, high altitude pulmonary edema, and high-altitude cerebral edema. Many people enjoy activities that allow them to get outside and take in some fresh air, but hikers, skiers, and others who are traveling to great heights must educate themselves about altitude sickness when planning their trip. This knowledge is important so that they can prevent or recognize it, and know what to do if they or one of their companions should become ill.
