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TPG contributor Katharine Gammon is a science writer for publications including WIRED, Popular Science and Los Angeles Magazine. When she’s not jetting to international conferences to interview some of the world’s leading scientific minds, she’s globetrotting herself, exploring unique destinations including recent trips to New Zealand and Southeast Asia. Today she writes about the science of altitude sickness and how travelers can prevent it from ruining their vacation.

Mountain bikers at the Montage Deer Valley outside Park City, Utah, have to contend with high altitude.

Who doesn’t get a thrill climbing a mountain or enjoying a panoramic view from up high?  Unfortunately, the altitude may not give you such a thrill. “Basically altitude sickness feels like a really nasty hangover,” says Dr. Grant Lipman, a Clinical Assistant Professor of Surgery in the Division of Emergency Medicine at Stanford University. “People get severe headaches and vomiting to start, then an altered level of responsiveness, and a rapid heart rate with shortness of breath at rest as things get worse.”

Sounds pretty nasty. One of the issues with altitude sickness is that it’s difficult to predict who will be among the unlucky few that have a truly difficult time with altitude.

No specific factors – such as age, sex, or physical condition – correlate with susceptibility to altitude sickness. Some people get it and some people don’t, and some people are more susceptible than others. “The biggest predictor of altitude sickness is if you’ve gotten it previously,” says Lipman.

Most people can go up to 8,000 feet without any ill effects. However, more than 25 percent of people who travel to high elevations each year, often to hike, camp or ski, will suffer from this condition.

The underlying mechanisms are pretty straightforward: the concentration of oxygen at sea level is about 21%. As altitude increases, the number of oxygen molecules per breath is reduced. At 12,000 feet, there are roughly 40% fewer oxygen molecules per breath. In order to properly oxygenate the body, a person’s breathing rate is forced to increase, even at rest. In addition, for reasons not entirely understood, high altitude and lower air pressure causes fluid to leak from the capillaries, causing fluid build-up in both the lungs and the brain. Continuing to higher altitudes without proper acclimatization can lead to potentially serious, even life-threatening illnesses.

Planning a trip to Machu Picchu? Make sure you’re prepared for the altitude – it sits at nearly 8,000 feet above sea level.

Until now, climbers and travelers have had a few weapons available to combat altitude sickness. They could take dexamethasone and acetazolamide or Diamox, a prescription-only drug – but those drugs had side effects. Lipman thought that other anti-inflammatory medications could help, so he set up a study to test the effectiveness of ibuprofen in helping with altitude sickness.

In the study, 58 men and 28 women traveled to an area of the White Mountains northeast of Bishop, California. They spent the night at 4,100 feet and were given either 600 milligrams of ibuprofen or a placebo at 8:00 am before heading up the mountain to a staging area at 11,700 feet. There, they were given a second dose at 2:00 pm. Then they hiked about 3 miles up to 12,570 feet, where they received a third dose at 8:00 pm before spending the night on the mountain.

Of the 44 participants who received ibuprofen, 19 (43 percent) suffered symptoms of altitude sickness, whereas 29 of the 42 participants (69 percent) receiving placebo had symptoms, according to the study. In other words, ibuprofen reduced the incidence of the illness by 26 percent.

Lipman says that the drug may work by reducing swelling near the brain, which reduces headaches and may help acclimatize travelers to the new altitude. He suggests that people take 600 mg or three 200 mg ibuprofen tablets, like Advil or Motrin, several hours before climbing to a higher elevation. Then he says that climbers should take a day off the drug to allow the body to acclimatize.

However, he warns that the clinical trial didn’t test travelers visiting altitudes above 12,500 feet – base camp at Mount Everest, for example, lies at 17,598 feet. “Most people will adjust in 2-3 days to altitude, but you may not have that kind of time to move slowly on vacation. If you really start to feel sick, the best thing to do is descend to last elevation you felt well at,” he says, adding “there is always more oxygen downhill.”

Even the base camp for Mount Everest lies nearly 18,000 feet above sea level!

Though not overwhelming, Lipman’s findings could prove especially useful for recreationists who have week-long vacations planned at high altitudes. “You don’t want to feel horrible for 15 to 20 percent of your vacation,” Lipman said. He says there are additional things travelers can do to help their bodies adjust to high altitudes. “Stay hydrated – drink until your pee is clear – and avoid sleeping pills or alcohol, which can lower respiratory drive. And most of all, get out there and have fun.”

What about you? Have you suffered from altitude sickness? What happened and how did you get over it?

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