Mark Wise is a Family Doctor
in Toronto, Ontario, who specializes in Tropical and Travel Medicine.
He is the Medical Advisor to VSO Canada. When not travelling himself,
he loves to talk and write about it.
Whether or not you have mastered
marathons and triathlons, you may be thinking of making your next
physical challenge a vertical one -- climbing a mountain. If you
do decide to head up into thin air, you had better be aware of the
risks of altitude sickness.
careful over 7,000 feet...
Most women are usually
not headed for Everest. Yet there are many other destinations
that pose a risk of altitude sickness -- The Andes, which
are above 10,000 feet, the peak of Mount Kilimanjaro at 19,340
feet, Mount Aconcagua in Argentina at 22,831 feet, and even
Aspen, which sits at 10,000 feet. In fact, symptoms may occur
at any altitude above 7,000 feet.
As we ascend, the partial
pressure of oxygen in the air decreases, and so we have less
oxygen for our red blood cells to deliver to vital organs
such as our brain and lungs. Your body responds to this challenge
in a positive way by increasing the heart rate and the respiratory
rate, diverting more blood to the brain, and given time, by
producing more red blood cells. However there are also harmful
changes that may occur, such as constriction of the pulmonary
circulation, and leakage of fluid from the blood vessels of
the lungs (high altitude pulmonary edema) and the brain (high
altitude cerebral edema).
How susceptible are you...
symptoms of altitude sickness will vary, and may depend
upon the altitude reached, the time taken to reach that
altitude, the time spent at the altitude, the degree of
exertion, and individual susceptibility. Those who spend
endless hours on treadmills do not seem to be at an advantage,
and in fact might be at greater risk due to their tendency
to rush up the mountain (perhaps guys fit into this category).
Individuals with a past history of altitude sickness, as
well as those who tend to retain fluids and hypoventilate,
are also at greater risk. And finally, sometimes those on
a budget need to be extra careful (I'm told that guides
on Mt. Kilimanjaro cost $100 US per day, so less affluent
climbers might push themselves to get up and hopefully down
taking birth control pills...
are probably not significantly different then men with respect
to their risk of altitude sickness. Occasionally you will
hear that being on the birth control pill at high altitudes
is not desirable. Here, the concern is that it might increase
one's risk of developing a blood clot. This suggestion is
not absolute, however, and one must weigh the small risk of
a blood clot against the possible risk of pregnancy, as sex
does occur at high altitudes!
Other factors which might
also contribute include dehydration, tight clothing, an increase
in your red blood cells, and the tendency to scrunch up in
small tents for prolonged periods.
mildest and most common of the altitude-related syndromes
is acute mountain sickness (AMS). If you want to find out
what altitude sickness in its mildest form feels like, try
a bottle of champagne and some vodka! Symptoms resemble a
hangover in many ways, with headache, nausea, vomiting, dizziness
and insomnia. If one ignores the symptoms and continues to
ascend, this may progress to high altitude cerebral edema
(HACE). In addition to the symptoms mentioned, unsteadiness
and irrational behaviour may he characteristic. Perhaps this
is the reason that unfortunate Everest climbers find themselves
falling into crevasses. HACE will proceed to coma and death
if it is not recognized and treated promptly. In addition,
high altitude pulmonary edema (HAPE) is characterized by decreased
exercise performance, a dry cough and shortness of breath.
It may coexist with AMS or HACE. Once again, if it goes unrecognized,
coma and death may be the end result.
you are intent on reaching a higher altitude, you need the
proper attitude and advice. If you must ascend rapidly, or
have a past history of altitude sickness, consider the use
of Diamox (acetazolamide) to prevent altitude sickness, This
drug contains sulfa, and should be avoided in those with sulfa
allergy. It may cause some tingling around the mouth and extremities.
It may also be used to treat the symptoms of mild altitude
Mild symptoms of AMS
may be treated simply with rest, Diamox, and simple analgesics
such as acetaminophen or ASA. More severe symptoms, particularly
HACE and HAPE, may need to be treated urgently with oxygen,
steroids, diuretics and most importantly, rapid descent. Portable,
pressurized bags (Gamow Bag) may be used when descent is not