I recently spent three days in Cusco, Peru, with a near-constant headache. Despite sleeping nearly 10 hours one night, I had no energy the next day, and climbing a few stairs felt like trudging up a mountain. My travel companion, who normally sleeps on his stomach, had to roll over to his back because he felt as though he couldn’t catch his breath. Our different symptoms had a single cause: We were suffering from altitude sickness.
Located at an elevation of more than 11,000 feet above sea level, Cusco is one of several high-altitude tourist destinations that can cause problems for travelers who aren’t used to the environment. Others include Breckenridge, Colorado (9,600 feet); Lhasa, Tibet (about 12,000 feet); and La Paz, Bolivia (where the airport is perched at a lofty 13,323 feet). Many trekkers also experience altitude sickness when climbing in the world’s highest mountain ranges, such as the Himalayas and the Andes.
What Is Altitude Sickness?
Also called elevation sickness, altitude sickness is caused by lower oxygen levels at high elevations, typically starting around 8,000 feet. Scientists don’t yet know why some travelers get altitude sickness and others don’t—there seems to be no correlation with age, gender, or level of fitness.
However, one known risk factor for altitude sickness is a rapid ascent, such as flying directly to a high-altitude city or climbing too quickly on a mountain trek. Your body can adjust to higher altitudes, but it may take several days to do so.
Altitude Sickness Symptoms
Altitude sickness is a term that encompasses multiple syndromes. The mildest and most common one is acute mountain sickness; symptoms typically include headache, nausea, fatigue, shortness of breath, trouble sleeping, loss of appetite, and dizziness.
“The symptoms are similar to those of a bad hangover,” says Dr. David Shlim, who served as the head of the Himalayan Rescue Association for more than 10 years and currently runs Jackson Hole Travel & Tropical Medicine in Wyoming. Exertion can make these symptoms worse.
Sometimes acute mountain sickness progresses to a more severe illness known as high-altitude cerebral edema (HACE), which involves swelling in the brain. Another form of elevation sickness is high-altitude pulmonary edema (HAPE), or accumulation of fluid in the lungs. Both conditions are life-threatening and require immediate treatment.
Warning signs to watch out for include breathlessness even when resting, a cough with frothy sputum, gurgling in the chest, fever, confusion, marked drowsiness, blue or purple discloration of the skin, and impaired coordination. If you or a travel companion experiences any of these symptoms, descend to a lower altitude and seek medical help at once.
How to Prevent Altitude Sickness
Careful itinerary planning is among the most important ways to prevent altitude sickness. Instead of flying directly into a high-altitude city and spending your first night there, consider descending to a lower elevation for the first few days of your trip. For example, many travelers to Cusco choose to stay in the nearby Sacred Valley for the first few nights of their trip in order to acclimatize more gradually.
Plan to take it easy when you first arrive at a higher elevation. “Altitude sickness typically strikes within 12 to 24 hours of exposure,” says Dr. Shlim. That means you shouldn’t count on hitting the slopes hard the first day of your Rocky Mountain ski vacation.
For those planning a trek, the medical team at Global Rescue, which provides evacuation and medical assistance, recommends spending a minimum of two days resting and acclimatizing at an altitude of at least 9,000 feet before you start your ascent. Make sure your climbing schedule includes rest days and that the pace is well within your abilities. The International Association for Medical Assistance to Travellers (IAMAT) warns that climbers should ascend no more than 300 meters (984 feet) per day.
Before any high-altitude trip, visit a travel clinic for a consultation. Your doctor may prescribe acetazolamide (often called Diamox), the most common altitude sickness medication. When you start taking it a day before arriving at altitude, it can help you acclimatize more quickly. Side effects include frequent urination and tingling in the hands and feet. Travelers with certain allergies may not be able to take acetazolamide.
A word on family travel: Children can take the same altitude sickness medications that adults do (in smaller doses), but Dr. Shlim cautions against bringing pre-verbal kids into a high-elevation environment because they won’t be able to tell you if something’s wrong. For older children, make sure your itinerary is paced appropriately for their abilities.
Altitude Sickness Treatment
If elevation sickness strikes despite your precautions, rest and avoid unnecessary exertion. “Drink plenty of tea, orange juice, and water,” says Dr. Gustavo Zubieta-Calleja of the High Altitude Pulmonary and Pathology Institute in La Paz, Bolivia. “Avoid alcohol and smoking. Have light meals and avoid milk.”
Dexamethasone, a steroid, relieves many altitude sickness symptoms, including those associated with HACE. But Dr. Shlim notes that dexamethasone doesn’t help with your body’s acclimatization process, so it shouldn’t be used when you’re still ascending. “It’s a rescue drug if you’re already sick,” says Dr. Shlim, “so it can help you descend on your own feet.”
Ibuprofen and aspirin can help with headaches, and oxygen treatments also offer relief for many travelers suffering cerebral or pulmonary symptoms.
As for herbal remedies, such as South America’s famed coca tea, medical opinions are mixed. “I believe coca tea has true effectiveness,” says Dr. Zubieta-Calleja. “Some experiments in mice have shown true positive protective effects.” The medical team at Global Rescue notes that studies of ginkgo biloba have produced “some positive results.”
Most important—especially for climbers—is acknowledging that you’re feeling ill and not trying to push past it, says Dr. Shlim. “Don’t go to a higher altitude if you have any symptoms—even mild ones. Descend if your symptoms get worse when you’re resting.”
Global Rescue offers the same bottom line: “Descent is the only definitive treatment for altitude-related illnesses.”
Have you ever experienced altitude sickness?
More from SmarterTravel:
- Altitude Sickness on Planes?
- 9 Products to Help You Stay Healthy While Traveling
- 8 Best Health Apps for Traveling
Follow Sarah Schlichter on Twitter @TravelEditor for more travel tips and inspiration.