Struggling at a Peak Moment
Years ago I was on a hike with a pal when I suddenly felt sick and bad-tempered. There we were at 11,000 feet, surrounded by crags, blue skies and gorgeous carpets of lupine and paintbrush blooms (“The Sound of Music” had nothing on this), and all I wanted to do was curl up in a ball by a stunted tree and be left alone.
A day or so later, still on the trail, I was again charging along with trusty stick in hand, belting out, “Pack up your troubles in your old kit bag--and smile! smile! smile!” (This may have been harder on my companion than the grumpiness.) My body had done its magical, physiological adjusting, and my mild case of “acute mountain sickness” was gone.
But what had my body done? And how? And why is it that people born and bred at very high altitude can prance around with ease at levels that make us lowlanders huff and puff if we reach for the TV remote? After close to 20 years, I decided it was time to find out--and called Dr. John West, editor of a journal called High Altitude Medicine and Biology.
A professor of medicine and physiology at UC San Diego, he’s been studying the body’s response to altitude for decades. He was recruited early in his career by famed mountaineer Edmund Hillary to do altitude studies in the Himalayas (such as getting people to ride stationary bikes atop a 19,000-foot glacier). Things just snowballed from there. In the ‘80s, West led a research team that camped out at 21,000 feet on Mt. Everest.
Thin air, of course, is the reason our bodies don’t work as efficiently high up. There’s less air pushing down from above, so the gases are more spread out. That means you take in less oxygen with each breath--and your cells feel the lack, leading to such symptoms as breathlessness, lightheadedness, headaches, difficulty sleeping and less-than-optimal thinking powers. (Sometimes people suffer from fluid in the lungs or--more rare and serious--a buildup of fluid in the brain. Treatment in both cases is getting the person down from the mountain as soon as possible.)
But people do adjust to altitude, thanks, among other things, to two clever sensors, one in the neck and one in the kidney. The one in the neck--the carotid body--senses the reduced amount of oxygen in our blood, and our breathing gets deeper and more rapid. The one in the kidney, which doesn’t have a fancy name, senses the low oxygen too, and sends an alert message to the bone marrow: Low oxygen! More red blood cells needed!
And so, over time, the blood of someone living high will become thicker with red cells, able to carry more oxygen. (This fancy trick probably evolved for reasons that had nothing to do with mountaineering, says West, such as helping the body fill up with the right amount of blood if some is lost from bleeding.)
Our magical kidneys help in another way--by sensing that our blood is less acidic at high altitude, which may also be making us feel sick. The organs do some chemical maneuvering to drag the pH back to normal levels.
People who’ve lived all their lives at high altitudes are already adjusted in these ways, but, contrary to popular belief, not all “highlanders” are full of vim and vigor, West says. Some suffer from “chronic mountain sickness.” Their blood is so full of red blood cells that it’s sticky and makes the heart work harder (and also makes the sufferers look kind of blue from all the hemoglobin). “They get very tired and sleepy, and sometimes they have to be treated by removing red blood cells,” West says.
People respond and adjust to altitude in different ways: Most sense it at 7,000 to 8,000 feet, but others can feel it at 5,000. Genes probably play a part--for highlanders too. There’s evidence that Tibetan mountain dwellers, whose families have lived up high for countless generations, are less prone to the sticky-blood sickness than highlanders of the Andes, whose ancestors haven’t lived in that region for as long.
These days, West is trying to make life easier for people who work in high places and live in low ones--such as mine workers in Chile and Caltech scientists who operate an observatory at 16,700 feet. At the observatory, “they’d be swinging around and bump things and make stupid and expensive errors,” West says. The solution: oxygen-enriched rooms that mimic a lower, more manageable altitude.
If I’d had oxygen on my trip, maybe I wouldn’t have kept that big, aromatic bag of apricots in my tent--but then we’d never have met the nice bear.
If you have an idea for a Booster Shots topic, write or e-mail Rosie Mestel at the Los Angeles Times, 202 W. 1st St., Los Angeles, CA 90012, rosie.mestel@latimes. com.