Many of the world’s most intriguing destinations exist at high elevations. For example, Santa Fe, New Mexico is 7,260 feet high. Peru’s Machu Picchu sits at 8,000 feet. Lhasa, Tibet soars almost 12,000 feet into the air.

Whether you plan a leisurely visit or a heavy-duty hiking expedition to similarly-situated locales, the possibility of encountering altitude illness must be a factor in trip planning. Altitude illness occurs when people travel to higher altitudes faster than the body can adapt to lower barometric pressure and the body’s decreasing efficiency in taking in oxygen. Acute mountain sickness is its mildest form, and the one which most non-extreme travelers have to consider. Early symptoms include headaches, fatigue and insomnia. The higher you go without proper acclimatization, the worse symptoms can get. In fact, they can be downright life-threatening.

How High is High?

For those who live at sea level, even arrival in a mile-high city like Denver might cause the onset of minor altitude-related symptoms, like dryness or headache. But for the most part, according to the Centers for Disease Control Yellowbook, “altitude illness sets in when going to 8,000 ft or higher.” The Yellowbook also cautions that susceptibility to altitude illness is often genetic, and risk is not impacted by physical fitness.

If you are planning a trip to an altitude in the neighborhood of 10,000 feet, here are some tips to prepare. Note that extreme trips to altitudes above 10,000 feet will likely require additional precautions and strategies.

1. Allow time for your body to catch up to the elevation. According to Jeff Stivers, REI Adventures program coordinator, “The common principle for high-altitude hiking trips is pacing of trips and acclimatization.” The process of acclimatization can take from three to five days. If starting from sea level, the first stop on a high-level itinerary should be at an altitude of about 5,000 feet. Once at 8,000 feet, it’s preferable to move up only one thousand feet a day.
2. Don’t Push It: Exercise performance will always be reduced compared with low altitude, due to the body’s decreasing ability to take in oxygen. Stivers recommends taking it slow the first few days at high altitudes, and then building up activity levels.
3. Drink Up: Dehydration can decrease the body’s ability to acclimatize. Travelers often arrive to destinations dehydrated after long plane flights. About one week before a trip begins, start drinking between 66 to 100 ounces of water a day. Keep a one liter (33.8 ounces) water bottle with you while traveling and sip frequently. Reducing caffeine and alcohol consumption before and during your trip will decrease chances of dehydration.
4. Eat Small, Eat Often: The body takes longer to digest food at higher altitudes. So, the best bet, according to REI Adventure’s Amy Hardie, is to eat a good breakfast, graze throughout the day, and eat a light dinner. That strategy provides ample energy during the day, while allowing for a better night’s sleep.
5. Ups and Downs: If you do start feeling sick as you ascend, the best bet is to go down. That will usually ease the symptoms. If you absolutely can’t descend, stop, rest, drink fluids and grab a bite to eat until symptoms subside.

Most travelers heading to high altitude tourism hot spots (as opposed to those scaling mountains) can acclimatize naturally just by taking it slow. Sometimes an aspirin is all it takes to fend off altitude-related headaches. However, if you have medicals issues, or you have previously suffered from altitude sickness, it’s best to check with a doctor or a travel medicine clinic in advance about the options. There are some prescription drugs that help the body adjust. Holistic remedies include natural supplements like ginkgo biloba, ginger, or coca leaves.

For a list of travel medicine clinics in the United States, visit the Traveler’s Health section of the Center for Disease Control website. And to cover all the bases, buy travel insurance in case the precautions you take do not fend off the necessity of seeking out medical care on a high-altitude trip.

Laura Powell is a travel expert based in Washington, DC. You can read more on her blog: The Daily Suitcase. 

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