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Earth Notes: Living at Altitude

Llamas are among several animals that have adapted to living at high altitude.
Llamas are among several animals that have adapted to living at high altitude.

Flagstaff, AZ – Living at high altitude presents challenges for all animals, especially when it comes to the availability of oxygen. At 7,000 feet, only 78 percent as much oxygen is available for use as at sea level.

As a result, visitors from Florida might notice that they have to breathe harder at high elevation. What they won't notice is the details of the changes going on inside their bodies.

As soon as someone reaches a higher altitude, a cascade of cellular reactions starts to take place in order to get enough oxygen to the tissues and brain. The formation of red blood cell increases; blood vessels widen; new blood vessels are formed in tissues; and cells begin anaerobic metabolism.

But how long it takes for a body to acclimate, or get used to the lower oxygen levels, depends on the individual and the altitude.

Populations of humans and other mammals that live at high altitude have already adapted to low oxygen levels. Researchers have long known that llamas and vicunas (vee-coon-yas) from the South American mountains have a particular form of hemoglobin that more readily attaches to the fewer available oxygen molecules. So do high-altitude Peruvian and Bolivian Indians.

Some mountain mice in Colorado have a genetic mutation that allows their hemoglobin to better deliver oxygen. Tibetan people, too, carry a gene that can help optimize metabolism in conditions of low oxygen.

Together, such adaptations ensure that the brain and body get enough usable oxygen to survive and enjoy high mountain landscapes.

-Cecile LeBlanc