Journey Woman - Journey Doctor - The Air Up There

The Air Up There -- Altitude Sickness

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.

Be 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...

The 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 more quickly).

Are you taking birth control pills...

Women 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.

Be aware of symptoms...

The 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.

Be aware of treatment...

If 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 sickness.

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 an option.

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