A man walks on the roof of the Sera Monastery in Lhasa, with the Potala Palace in the background. The city is 11,978 feet above sea level. (Johannes Eisele/AFP/Getty Images)

When I told friends I was going to Tibet last spring, almost everyone asked, “What are you doing to prevent altitude sickness?”

Not nearly enough, it turned out, given the headaches, insomnia and occasional wooziness I experienced during four days in Lhasa. The Tibetan capital rises from the Himalayan Plateau to 11,978 feet above sea level — more than twice the elevation of Denver.

Already badly jet-lagged after deplaning in Lhasa, I suddenly faced one-third less breathable oxygen than in the low-lying cities I’d just left: Beijing, Los Angeles and the District, where I live. Even our not-so-rigorous Tibetan sojourn — which involved some walking, multiple bus rides and the occasional long or steep climb to a palace or monastery — played havoc with my head, heart and lungs.

Road Scholar, our Boston-based tour operator, had advised us to increase our pre-trip aerobic exercise and deep breathing for several months to improve stamina, and insisted that we consult doctors to learn about altitude sickness risks and remedies. But because we had flown straight from sea level in Beijing to more than two miles up in Lhasa without giving our bodies time to acclimate, some of us were shocked by how awful we felt.

What is altitude sickness? Put simply, it’s the body’s reaction to decreased oxygen levels. We lose 3 percent of inhaled oxygen molecules for every 1,000 vertical feet traveled, according to altitude researchers. To compensate for the lack, travelers inhale more frequently and can feel out of breath. With additional symptoms including headache, nausea, vomiting, dizziness and fatigue, altitude sickness can mimic a really bad hangover.

There are three types of altitude-induced illness. Fortunately, only the mildest type struck some in our 11-member group: acute mountain sickness (AMS), commonly called altitude sickness. Two related and potentially fatal ailments can occur when lower air pressure and higher altitudes cause capillaries to leak: high altitude pulmonary edema (HAPE), a buildup of fluids in the lungs; and high altitude cerebral edema (HACE), a buildup of fluid in the brain. In extreme cases, AMS can become HAPE or HACE, or the illnesses can develop on their own without being preceded by the milder one.

Regardless of age, sex, body type and fitness level, one or more of these maladies can hit anyone at any high-altitude location — including Antarctica — according to medical experts. Two years ago, former astronaut Edwin “Buzz” Aldrin, then a hale 86, had to be airlifted from an elevation of 9,300 feet in the South Pole. Congested lungs kept him in a New Zealand hospital for a week.


Climbers cross the Khumbu Icefall of Mount Everest. Altitude researchers say we lose 3 percent of inhaled oxygen molecules for every 1,000 vertical feet traveled. (Prakash Mathema/AFP/Getty Images)

If you’re planning a high-altitude adventure, a bit of prevention could save your vacation — if not your life. Discomfort can set in as low as 3,000 feet for those with lung disease; for others, problems won’t appear until around 8,000 feet. For context, Mount Everest, the world’s tallest peak, rises to 29,029 feet; Alaska’s Denali, the highest U.S. peak, hits 20,310 feet; and Mount Kilimanjaro in Tanzania stops at 19,341 feet.

The best strategy, as Road Scholar noted, is to acclimate the body at lower elevations before heading skyward. A pair of hiker friends recently learned the hard way what results from a steep ascent, rather than gradual one. Marketing executive Linda Roth and her lawyer husband, Jonathan Kahan, flew from their home in the Washington area (410 feet) to Dallas (430 feet) to Montrose, Colo., (5,807 feet), then drove two hours to Telluride (8,750 feet), where they went on a gondola ride that took them higher. Roth successfully treated her initial dizziness with extra water and a massage at the hotel spa. Kahan, a diet-soda drinker, added water but remained sluggish and slightly nauseated in Telluride.

“He didn’t fully get better until three days in,” Roth says.

Another way to sidestep AMS is to “climb up and sleep down” at less strenuous lower altitudes. This means heading to higher ground from your hotel or base camp but spending the night at the starting point or another less-elevated site where there is greater oxygen density.

Many high-altitude seekers rely on Diamox, a popular prescription drug that “stimulates breathing and raises your oxygen level,” says Peter Hackett of Telluride, Colo., an emergency medicine physician, altitude sickness expert and experienced mountaineer. Yes, you’ll urinate more often, carbonated drinks may taste odd and your toes and fingers will tingle, he explains, but those are temporary and harmless side effects. While the body usually needs two to four days to adjust to high altitudes, “Diamox does the same thing in about eight hours, speeding the natural process,” says Hackett, noting that the drug works for 85 to 90 percent of people.


Climbers, at right, try to get a clear view of Mount Everest. When trekker Tom Healy skipped his Diamox on a 2013 trip to Nepal, he says, altitude sickness stopped him in his tracks at 17,000 feet. (Roberto Schmidt/AFP/Getty Images)

Tom Healy, 57, a poet living in Miami and Manhattan, who I know as an avid global climber and trekker, skipped Diamox on a 2013 trip to Nepal. The result? At about 17,000 feet in the Mount Everest base camp region, he simply stopped in his tracks. A Sherpa quickly loaded him onto a donkey and took him down more than 1,000 feet to stabilize. He rested, warmed up and was revived with protein-rich yak milk gruel and some dried yak meat.

“Within six hours I felt better and decided to catch up with my friends,” Healy told me. A day and a half later, climber and Sherpa found their group. “It was about machismo, and the big question: ‘Are you going to summit?’ ”

I also checked in with novelist Russell Banks, who has climbed mountains on four continents. He says he suffered his lone bout of altitude sickness when a delayed flight from Albany, N.Y., cost him a day and night of acclimatizing at 10,000 feet in Quito, Ecuador. He and his better-acclimated pals were climbing Volcan Cayambe (just under 19,000 feet) in the Andes when Banks was struck by a headache and vomiting. “I was not so sick that I had to go down. I had Diamox, and I just popped those.”

Now 78, Banks has given up high-altitude adventures, but he happily offers this advice: “Always acclimatize, and don’t wait until you’re sick to start taking Diamox. Just take it, because it can’t hurt you.”


A foggy morning view of Volcan Cayambe in Ecuador. Author Russell Banks says altitude sickness struck here after a delayed flight cost him a day and night of acclimatizing at 10,000 feet in Quito. (Sergii Broshevan/Alamy Stock Photo)

There are also favorite local remedies: yak butter tea in the Himalayas, which our Tibetan and Nepali guides swore by, and coca leaf tea, containing minuscule traces of the alkaline known as cocaine — the highly processed drug that shares its name uses the leaves — and widely served in the Andean regions of South America, which several of my fellow travelers had savored in Cusco, Peru (11,152 feet). Alas, the tea is banned in the United States.

Many hotels in mountainous areas pump extra oxygen into guest rooms, especially overnight; others provide small personal oxygen canisters or portable units in rooms. I used a machine the size of a small radiator in Lhasa. It cost $5 per hour, sterile nose hose included. During those 60 minutes, I felt marginally better, although the headache roared back afterward because the body can’t store supplemental oxygen. I could have kicked myself during our time in Lhasa for stupidly, inexplicably choosing not to take the Diamox I’d brought along.

Sometimes, the cure can be mistaken for the ailment. Conventional wisdom urges high-altitude travelers to temporarily avoid caffeine, a diuretic that hastens dehydration and constricts capillaries. Consequently, what seems like altitude sickness can, in fact, be caffeine withdrawal, which struck one group member who usually downs eight to 10 cups of black tea a day.

Hackett, the physician, emphasizes that “the most important factor of whether or not you get sick is how fast you go high.” If you’re headed to Telluride, he suggests, spend the first day or two in Denver or Montrose, both at significantly lower elevations than the ultimate destination.

That layover, says Hackett, could mean the difference between a great vacation and a nasty bout of altitude sickness. Or worse.

Groer is a writer based in the District.

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