Altitude sickness occurs when you cannot get enough oxygen from the air at high
altitudes. This causes symptoms such as a headache, loss of appetite, and trouble sleeping.
It happens most often when people who are not used to high altitudes go quickly
from lower altitudes to
8000 ft (2438 m) or higher. For
example, you may get a headache when you drive over a high mountain pass, hike
to a high altitude, or arrive at a mountain resort.
sickness is common. In the United States, more than 20% of people visiting the
western mountains get it.1 Experts do not know who
will get it and who will not. Being male or female and your fitness level play no role in whether you get altitude sickness.
Recommended Related to Lung Disease/Respiratory Problems
sickness can be dangerous. It is smart to take special care if you go
high-altitude hiking or camping (like in the Rockies) or have plans for a
vacation or trek in high-altitude countries like Peru, Ecuador, or
Altitude sickness is also called acute mountain
What causes altitude sickness?
Air is "thinner" at
high altitudes. When you go too high too fast, your body cannot get as much
oxygen as it needs. This causes the headache and other symptoms of altitude
sickness. As your body gets used to the altitude, the symptoms go away.
What are the symptoms?
The symptoms of altitude
A headache, which is usually
throbbing. It gets worse during the night and when you wake up.
Feeling weak and lazy. In severe cases, you do not have the
energy to eat, dress yourself, or do anything.
Waking up during the
night and not sleeping well.
Your symptoms may be mild to severe. They may not start
until a day after you have been at a high altitude. Many people say altitude
sickness feels like having a hangover.
Altitude sickness can
affect your lungs and brain. When this happens, symptoms include being
confused, not being able to walk straight (ataxia),
feeling faint, and having blue or gray lips or fingernails. When you breathe,
you may hear a sound like a paper bag being crumpled. These symptoms mean the
condition is severe. It may be deadly.
If you are going on a
high-altitude trek, learn about altitude sickness, its symptoms, and
how to treat it. Look out for other people in your group. You can learn more about altitude
sickness at the International Society for Mountain Medicine website at
How is altitude sickness diagnosed?
If you are at
a high altitude, your doctor may think you have this condition. Your doctor
will ask you questions about your symptoms and examine you. To rule out other
conditions, your doctor may ask if you have been drinking fluids or alcohol or
using any medicines, or if you have a cold or the flu.