How to avoid high altitude sickness if you’re heading for the mountains

Hikers in Aspen, CO. (Steve Haggerty Photo)

I’m heading to Colorado for vacation at the end of the month, and all I keep hearing about—besides the state’s breathtaking beauty—are tales of high-altitude sickness. One of my friends told me she was up all night with a massive headache and shortness of breath while camping in the Colorado Rockies at 8,000 feet. Another told me she developed fluid on her lungs at a similar altitude. My mom reminded me that my father got unrelenting mountain sickness and had to leave a relative’s wedding in Breckenridge, 10,000 feet above sea level, before the ceremony.

I, myself, have never been higher than Mexico City, about 7,300 feet, and have no idea how my body will react to higher elevations. Fortunately, one of the perks of my job is that I get to call experts to answer my pressing health questions. High altitude sickness researcher Dr. Stuart Harris, a mountaineer who heads the wilderness medicine division at Massachusetts General Hospital, was happy to oblige. Here are his edited comments.

What’s the best elevation to start at when you’re traveling in from sea level?

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Spending a night or two at the altitude of Denver or Boulder, about 5,000 to 6,000 feet above sea level, will help you acclimate without any effects of altitude sickness. From there, you can rise to 8,000 feet and then to 10,000 or 11,000 feet. It generally takes your body about three to five days to adjust to a new elevation.

More and more, people are flying from sea-level cities such as Boston directly into very high-altitude cities such as Lhasa in Tibet, which is nearly 12,000 feet above sea level. That’s not a good idea and almost certain to cause acute mountain sickness.

What causes high altitude problems, and are some people more prone than others?

Acute mountain sickness occurs from lower air pressure and oxygen levels at high altitudes that leave your body unable to take in enough oxygen for proper functioning. This can cause headaches, dizziness, fatigue, confusion, shortness of breath, loss of appetite, and trouble sleeping. The faster you ascend to a high altitude, the more likely you are to develop such symptoms.

Some people are more prone to altitude sickness and can develop severe complications such as fluid on the lungs—called high altitude pulmonary edema—but that’s rare at altitudes below 10,000 feet. Unfortunately, we don’t know how to predict who will develop life-threatening altitude problems; researchers are studying genetic patterns to see if they can uncover common gene mutations that could better predict risk. For now, the best way to know if you’re at risk for severe problems is if you’ve had them before.

How does the body acclimate?

Within a few days, you’ll increase your breathing rate to take in more oxygen. Other systems in your body adjust as well; for instance, your kidneys will excrete more bicarbonate in the urine in order to accommodate your faster breathing rate. That will cause you to urinate more frequently. After several weeks, your body will produce more red blood cells to become more efficient at transporting oxygen.

Which remedies are most effective for alleviating symptoms?

Going to a lower altitude is the best remedy. Acetaminophen, ibuprofen, or another over-the-counter pain reliever can be used to treat headaches, but it may not work in severe cases. Some ski resorts keep portable oxygen tanks available for rent, which can help until your body acclimates. Avoiding physical exertion can also help.

Can any medications help speed the acclimation process?

Yes, you can get a prescription for acetazolamide (Diamox), which causes your kidneys to excrete bicarbonate more quickly, helping you speed your breathing rate in a shorter period of time. It may cause dizziness or drowsiness and heightens your skin’s sensitivity to sunlight, so it should be used with sunscreen.

Dexamethasone, a steroid, is also used to alleviate symptoms of mountain sickness; steroids suppress the immune system, however, making it easier to get an infection or worsening an infection you already have. The other problem with this drug is that if you run out while at a high altitude, your symptoms come back multiplied. Neither Diamox nor dexamethasone should be used in young children to prevent mountain sickness because their safety hasn’t been adequately tested.