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Adventure Travel

Fighting Altitude Sickness

What happens when you go from sea level to altitude too fast? One brave editor found out the hard way, and offers her blow-by-blow findings in hopes that you don't suffer a similar fate.

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Elevation: 8,024 feet

Friday, 4:30 p.m.

I’m standing at the dusty, isolated Weatherford Trail, just outside Flagstaff, Arizona. With me are Backpacker Southwest Editor Annette McGivney, her husband, Mike, and their toddler, Austin. I just finished strapping a heart-rate monitor around my ribs. Its watchlike display encircles my left wrist. A digital watch adorns my right. An altimeter dangles from my pack. Add a pocket protector and I’d be the epitome of backpacking geekdom.

All this electronic paraphernalia-Annette, too, for that matter-will help monitor my general well-being during a typical three-day trip up and into the San Francisco mountains. There is nothing wrong with me physically. I am a healthy, 36-year-old experienced backpacker who lifts weights and runs 25 miles a week. Yet there’s a very good chance I’ll get sick this weekend. At least, that’s the plan.

My first (and only other) brush with altitude sickness came some 12 years ago, the day after driving from Los Angeles to 8,000 feet in the Sierra Nevada. The next day, we hiked to 10,000 feet, where a nasty headache forced me to go to bed early. I recovered overnight, though, and reached the 12,000-foot summit the next morning.

This time, I’ve hurtled my body from my nearly sea-level home to the trailhead in less than 12 hours. In a couple more hours, I will have hiked another thousand feet or so. Tomorrow, we hope to summit 12,633-foot Humphreys Peak. (See “Top Of The World” on page 61 for trail information.) It’s a typical vacation scenario for time-pressed backpackers.

Apart from reaching the top of Humphreys, my goals are: A) to show that going too high too fast is a prescription for acute mountain sickness (AMS, also known as altitude illness); and B) to make it clear that you can keep AMS from ruining your time in the mountains.

So far, simply shouldering my 40-plus-pound pack at this elevation has me panting like a poodle on hot pavement. Four-thirty is late to be hitting the trail, but the summer sun will be hanging around for several more hours, and we plan on hiking just a couple of miles before making camp. Besides, it’s Friday, and I’m anxious for sweet mountain air to empty my head of office worries.

Mike inquires about my next of kin. I tighten my hipbelt, adjust my trekking poles, and follow Annette into Coconino National Forest. The path weaves among immense ponderosa and Scotch pines squatting like escapees from a Christmas tree farm. Solitary aspen, as big as I can reach around, soon appear. Annette asks if I fall into the butterscotch or vanilla camp regarding the smell of ponderosa pine bark. I lean close to a craggy specimen that soars above us like an orange-barked rocket and inhale deeply. It’s like sniffing a fine chardonnay: vanilla, I decide, with citrusy overtones.

We hike for a while in silence, immersed in the sights, sounds, and aromas. But it doesn’t take long before I call to Annette, “Wait up!…We’ve got…to…switch…places.” With every wheezing step, I’m falling farther behind her long legs and effortless, acclimatized pace (her Flagstaff home is at 6,500 feet), and my head feels slightly detached, like I’ve guzzled a beer on an empty stomach.

“Sure,” shrugs Annette, backtracking. “You feeling the altitude already?” She’s oblivious to my dagger looks, idly shifting her pack as she waits for me to stop making Darth Vader noises.

After another 90 minutes and a 1,000-foot elevation gain, we drop our packs for a few tests designed to catch the early signs of AMS (more on this later). First comes the tandem gait test, a less humiliating version of the roadside heel-to-toe walk along a straight line. Rock juggling comes next, which I abruptly abandon while several dayhikers pass. I smile and wave, feigning nonchalance while sucking on a smashed finger. They wave nervously, and hustle on by.

Finally, I rip off 10 jumping jacks. I’m winded, but still feel pretty good. I may survive after all.

All joking aside, AMS can be serious business, and no one is immune. About a quarter of all those who go to even moderate altitudes of 6,000 to 9,500 feet will feel some degree of its symptoms. Up the ante to even higher elevations and the symptoms become more severe; those who continue anyway may die.

As for me, my scenario is “typical for some of the high performance, stressed individuals who try to do too much too fast,” according to Charles Houston, M.D., of Burlington, Vermont, world-renowned for his 50-plus years of research in high altitude medicine. By climbing so quickly, I starved my body of the essence of life: oxygen. In response, a chain of automatic reactions began in an attempt to compensate.

First, the lack of oxygen in my blood sent a message to my brain: Breathe faster, stupid. My heart also began to pump faster and with more force to move blood, and the oxygen it carries, through my system more quickly.

“Acclimatization helps the cells get along on a smaller oxygen budget,” Dr. Houston says. Given more time and a slower gain in altitude, my body would gradually adjust and allow me to enjoy high-altitude backpacking with few, if any, symptoms of AMS.

But I wasn’t here to take my time.

Elevation: 9,400 feet

7:15 p.m.

Almost 1,400 feet higher up the mountain and I’m decidedly more light-headed, stumbling a bit, and giggling a lot. It’s important to note that on a list of phrases ordinarily used to describe me, “giggles a lot” would fall near the bottom, just after “likes to wear pink lacy things.” I turn on my tape recorder and state that Annette may have to start “tarrying the cape recorder.” More giggles. I perform the required tests without too much bungling, though I can’t figure out how long we’ll need to reach the top of Humphreys tomorrow at our current rate of ascent. It takes me 3 full minutes to do the math.

We haul the packs down to a protected, much-used campsite in a narrow little valley just off the trail and begin the familiar routines. I manage to set up the tent without impaling myself while Annette, choosing to keep me away from open flames, starts dinner. My appetite is unaffected, at least, and I devour a big bowl of curried lentil stew with garlic Melba toasts, washing it down with lots of water. (Dehydration, though a good way to promote AMS, is not a hardship I’m willing to risk.) While hanging our bear bags, I spot two faint and fast shooting stars in the slice of blackness above us-a good omen for tomorrow, I decide.

I wear the heart monitor to bed and record my lowest rate of the day just before nodding off: 76 beats per minute, as opposed to my sea-level resting rate of 55. Annette’s is an unremarkable 59.

I wasn’t showing clear symptoms of AMS yet, but my mental stumbling was typical of getting high. “It is well-known that mental tasks can be performed accurately at high altitudes,” says Ken Zafren, M.D., medical director of the Denali National Park Mountaineering Rangers in Alaska and associate medical director of the Himalayan Rescue Association, “but often take longer than at sea level.” An accompanying headache or lack of appetite, though, would have been a clear sign to stay put until all symptoms improved.

Some of my slow-wittedness also could have been chalked up to general fatigue. By the time we stopped for the night, I’d gained 9,000 feet of elevation in about 15 hours. Annette’s lower heart rate indicated that her body was struggling much less than mine, testimony to the wisdom of climbing just 3,000 feet in elevation for one day. As a rule of thumb, experts recommend that at elevations above 5,000 feet, travelers should climb no more than 2,000 feet per day. You can climb higher as long as you descend to sleep at or below that 2,000-foot mark.

Elevation: 11,430 feet

Saturday, 1:30 p.m.

Midway up what seems an endless switchback, I’m doubled over, gulping the thinning air like a goldfish on carpet. The day started well enough, even though I awoke four or five times during the night. We were on the trail by 8:30 after a decent breakfast, and lunch was a restful repast in a sun-dappled grove of spruce and pine.

But just after lunch, a nagging ache took hold behind my eyes and it has translated to a permanent squint. We’re above treeline now and hiking into a buffeting wind so strong that at times we stand in place, unable to make headway against the force. Tall, skinny Annette catches the wind like a sail and there are moments when I fear she’ll be lifted off the narrow ledge of trail and into the canyon nearly 1,000 feet below. This is starting to be not so fun.

Elevation: 12,070 feet

3:00 p.m.

I’m sitting with my head in my hands, trying not to move or talk. The slightest motion makes my head throb. I don’t need the heart-rate monitor because I can hear my pulse; it’s that bass drum pounding between my temples. We’re a few hundred vertical feet from the top, our packs stashed behind some boulders at a saddle where the summit trail branched off. I thought that without the extra weight I could make it, but I’ve been kicking and tripping over rocks like a drunk after an all-nighter.

“I stumble all the time, but usually you don’t,” Annette points out above the roar of the wind, now pummeling us with 50 mph gusts. She stands over me, her brow furrowed with concern, snapping pictures to document my exact shade of green as the nausea sets in.

“I have to turn around,” I mumble, finally. Normally it would kill me to stop this close to the top. But today, at this particular moment, the top of Humphreys seems as distant as the summit of Everest. I don’t even look back as we pick our way down through the boulders. I just want to get down, to feel better.

While not fully realizing it-or much of anything at the time-I was in the throes of AMS, according to Dr. Houston. The nausea, headache, fatigue, and mental confusion all pointed to the obvious: I should have gone more slowly. If I’d spent a night in Flagstaff, I might have been slightly better off, though Dr. Houston says that “a full day and night would have been best.”

Both Doctors Houston and Zafren stress that ascending at a reasonable pace is always the best insurance against AMS, but they also recommend the prescription drug acetazolamide (Diamox) as a preventive and treatment for AMS when you don’t have time or opportunity to acclimatize. They recommend 125 milligrams twice daily, starting the day before you begin to ascend and continuing for 24 hours after you arrive at the highest point. Since many doctors are ill-informed about altitude illness and Diamox, help yours get up to speed by doing some research ahead of time on the topic (Dr. Houston’s book is a good place to start; see “Resources” below.)

Dr. Houston also notes that ibuprofen “is a little more effective than aspirin at relieving the headache, but doesn’t change other symptoms.”

Elevation: 9,600 feet

5:25 p.m.

We make good time going down, and the wind subsides once we’re in the protection of big trees. For all I care, though, we could be walking through a stump-filled wasteland; my senses are numb. The headache and nausea haven’t abated, and I try not to snarl as we pass some cheery dayhikers. Sips of water don’t help.

Finally, we stop to check the distance to the Arizona Snow Bowl, a local ski area where we’ll call Mike to pick us up. It was to be our water stop for tonight’s camp, but I see no point in continuing this misery. I’ve accomplished my mission and am ready to bail.

We take off our packs, and I sulk while Annette pulls out the map.

“Do you feel like eating anything?” she asks.

A moaning “Oh God, no” is all I manage before throwing myself across a trailside log and retching violently, keeping a white-knuckle grip on my water bottle. I am suddenly struck by the thought that our lunch-cheese-peanut butter crackers and baby carrots-was much too orange. Between heaves, I hear a soft “click, click” and realize Annette, dedicated journalist to the end, is capturing my indignity on film.

I flop back down by the log and drag a sleeve across my mouth. “That doesn’t seem very low-impact,” Annette drawls in her driest West Texas tones.

The trip down is a blur. I feel better immediately after throwing up, but my respite is short-lived. By the time we reach the Snow Bowl, I’m again flat on my back fighting nausea. I lose that battle, as well as another skirmish on the way down the serpentine road after Mike picks us up. After two days of dry, dust-caked hiking, the only thing I manage to take off is my boots before collapsing grimy and exhausted on a bed at Annette and Mike’s house. Five hours later, I’m able to take a shower, then pass out again until 8 the next morning. I awake weak and still queasy, but on the mend.

It took me two full days to feel strong and steady again after that trip, and thinking back on it still makes me queasy. Next time, I’ll take that extra day or so to give my body the time it needs to adjust. Still, I can’t help but wonder if altitude will always be a challenge for me.

While various theories explain why some people react so badly to altitude, none have held up under scrutiny. “The cause of AMS and the reason Diamox works are both subjects of active debate among the experts,” says Dr. Zafren. “The answers are not in.” The latest research indicates that both High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE), more serious conditions that may follow AMS, are due to leaking blood vessels in the lungs and brain that cause life-threatening fluid buildup, or edema, in those critical organs.

Researchers are seeking answers to these and a slew of other altitude-related questions on mountains and in labs all over the world. And who knows? Maybe some day you’ll be able to rush from sea-level desktop to mountaintop in a weekend. Until then, use AMS to your advantage; there’s no better excuse for adding an extra day or two to your vacation.


Dr. Houston’s Going Higher: Oxygen, Man, & Mountains, 4th edition (1998; The Mountaineers Books; 800-553-4453; $22.50) is a thorough and readable treatment of the history, prevention, and treatment of altitude-related illness.

Also from The Mountaineers Books, Altitude Illness: Prevention & Treatment, by Stephen Bezruchka, M.D. (1994; $6.95), is small enough to take along in your first-aid kit and includes a handy reference chart of symptoms and treatment.

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