Topic Overview
What is altitude sickness?
Altitude sickness
occurs when you cannot get enough oxygen from the air at high
altitudes. This causes symptoms such as a headache and not feeling like eating.
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.
Mild altitude
sickness is common. In the United States, more than 20% of people visiting the
western mountains have it.
1
Experts do not know who
will get it and who will not. Being male or female and how physically fit you
are play no role in whether you get altitude sickness.
Altitude
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
Nepal.
Altitude sickness is also called acute mountain
sickness.
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
sickness include:
- Having a headache. The headache is usually
throbbing. It gets worse during the night and when you wake up.
- Not
feeling like eating.
- Feeling sick to your stomach. You may
vomit.
- 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.
- Feeling dizzy.
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, tell your group about altitude sickness, its symptoms, and
how to treat it. Look out for each other. You can learn more about altitude
sickness at the International Society for Mountain Medicine Web site at
www.ismmed.org.
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.
If you are
hiking or camping, you and those with you need to know the symptoms of altitude
sickness. People often mistake altitude sickness for the flu, a hangover, not
getting enough fluids, or feeling tired. As a rule, consider your symptoms to
be altitude sickness unless you can prove they are not.
How is it treated?
The best treatment for
altitude sickness is to go to a lower altitude. But if you have mild symptoms,
you may be able to stay at that altitude and let your body get used to it.
Symptoms often occur if you have just arrived at a mountain resort from a lower
altitude.
You may also be able to use oxygen or a specially
designed pressure chamber to treat altitude sickness.
If you stay
at a high altitude, rest. You can explore the area, but take it easy. Limit any
walking or activity. Drink plenty of water, but do not drink alcohol. Do not go
to a higher altitude until your symptoms go away. This may take from 12 hours
to 3 or 4 days.
For the headache,
you can take an over-the-counter medicine, such as acetaminophen (Tylenol),
ibuprofen (Advil, Motrin), or naproxen (Aleve). Do not give aspirin to anyone
younger than 20. Aspirin has been linked to
Reye syndrome
, a serious illness. You may also use
medicine to reduce feeling sick to your stomach or other symptoms.
A doctor
can give you acetazolamide (Diamox). This speeds up how fast your body gets
used to the a higher altitude. Nifedipine (Procardia) and dexamethasone are
also used for altitude sickness. You may also be able to use oxygen or a
specially designed pressure chamber to treat altitude sickness.
Go to a lower altitude if your symptoms are moderate to severe, they get
worse, or medicine or oxygen treatment does not help. Go down at least
1500 ft (457 m). Go to a lower
altitude as fast as you can or get emergency help if someone with you has
severe symptoms such as being confused or not being able to walk straight. Go
with the person. Never let someone with severe altitude sickness go down
alone.
Can I prevent altitude sickness?
You may be able
to prevent altitude sickness by taking your time when you go to high altitudes,
using medicine in advance, and eating certain foods.
- If you go to altitudes higher than
8000 ft (2438 m), try to spend
a night at a medium altitude before going higher. For example, in the United
States, spend a night in Denver before going to the Rocky Mountains.
- Do not fly into high-altitude cities. If this is not
possible, avoid large meals, alcohol, and being very active after you arrive.
Rest, and drink plenty of liquids. Talk to your doctor about taking
acetazolamide before you arrive. If you have symptoms, do not go higher until
they have gone away. Examples of high-altitude cities include Cuzco, Peru; La
Paz, Bolivia; and Lhasa, Tibet.
- Sleep at an altitude that is
lower than the altitude you were at during the day. For example, if you ski at
9500 ft (2896 m) during the
day, sleep the night before and the night after at
8000 ft (2438 m). "Climb high,
sleep low" is standard practice for those who spend time at high
altitudes.
- You may consider taking acetazolamide (Diamox) before going
to a high altitude. Talk to your doctor about this.
- Eat a lot of
carbohydrate. This include breads, cereals, grains, and pasta.
What if I have a lung problem or other disease?
Experts do not know much about how altitude affects other diseases. Many
people with
allergic asthma
do better at high altitudes. Still, if
you have asthma and are going to high altitudes, continue to use your usual
medicine and take your reliever medicine with you. Talk with your doctor about
altitude sickness if you have long-term diseases, especially heart problems,
sickle cell anemia
,
chronic obstructive pulmonary disease
, or
sleep apnea
.
