Prevent Altitude Sickness ... Without Coca Leaves - OZY | A Modern Media Company

Prevent Altitude Sickness ... Without Coca Leaves

Prevent Altitude Sickness ... Without Coca Leaves

By Nick Dall

Planning to get higher than 8,000 feet on a hike? Coca is not going to help.
SourceNick Dall


Because getting into trouble on a mountain can get you dead.

By Nick Dall

Reaching the summit of the third 12,800 foot pass, I had to sit down. Despite chewing coca leaves since we set off, my head was pounding and I couldn’t even look at the bowl of tuna and rice that my body so sorely needed. The dramatic Andean vistas went unappreciated. Fortunately, the rest of the day’s hike was all downhill and soon I felt a whole lot better.

Somehow I managed to avoid contracting acute mountain sickness (AMS) but — after discussing my choices with two Peruvian doctors who specialize in the condition — I realize that this was not for lack of trying. By only giving myself a couple of days to acclimatize and then chewing coca leaves, I had committed two cardinal errors. The first can be attributed to pure foolishness, but the second stemmed from my blind belief in the power of coca leaves to stave off symptoms. 


An ancient Inca path to the south of Huamachuco. The saddle to the top left is where the author started feeling at his lowest ebb.

Source Nick Dall

“Existing scientific evidence does not support the use of coca leaf tea in the prevention of AMS,” writes Dr. Joel Salinas. In fact, ingesting coca tea can actually “increase the symptoms of AMS.” This may come as a surprise to even seasoned hikers, and those accustomed to seeing Andean hotels dole out complimentary cups of coca leaf tea and hiking guides press palmfuls of coca leaves on their charges. 

In some cases we wonder, why did this man even try this hike? 

Dr. Eduardo Luna, travel doctor

Till recently, coca leaves — which have been used by locals to stay awake and to suppress the appetite for over 3,000 years — have been widely considered an effective traditional remedy for altitude sickness. While a physically fit person can experience a “mild placebo effect” from drinking a cup of coca tea at altitude (the biggest benefit, Salinas explains over the phone, comes from the water), the potential pitfalls far outweigh any benefits.

When you drink coca tea, explains Salinas, you are “ingesting a tiny amount of cocaine.” Chewing coca leaves — especially if you activate them with “cal” or limestone as the locals do — has even more of an effect on your nervous system, and has been proven to exacerbate the symptoms of AMS. 

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The town of Mollepata in northern Peru is perched on the edge of a canyon.

Source Nick Dall

But it’s not only the cocaine you should be worried about, says Salinas. Coca leaves also contain at least four toxic alkaloids and they’re often laced with insecticides too. What’s more, adds Dr. Eduardo Luna, a travel doctor at Samaritan Medical Services in Cusco, the leaves can be an extremely efficient vector of diarrhea, as their supply chain doesn’t come close to HACCP standards. 

Even Gualberto Vargas, a seasoned Andean trekking guide, has ditched the leaf. “I prefer to work with water. Lots of water.” Keep hydrated, do some pre-trip training and walk really, really slowly are his No. 1 tips.

Prevent AMS With These Clinically Proven Preparation Techniques:

  • Sleep in a hyperbaric tent in the run-up to your trip (expensive, weird). 
  • Breathe through a straw — 30 breaths, twice a day — for six weeks prior to your trip (cheap, weird). 
  • Practice breath-holding drills. Contrary to popular belief, you don’t have to do them in the tub.

Luna says that preventing AMS (and its even gnarlier cousin, high-altitude pulmonary edema, or HAPE — basically fluid on the lungs) “starts with the design of your itinerary.” Try to spend a few days at around 6,000 or 7,000 feet (in Peru, the city of Arequipa is a good first stop) before jumping a further thousand feet or so every couple of days. If this kind of leisurely approach is not possible, prescription altitude medication is your friend.

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Hiking into Mollepata after five days on ancient Inca roads.

Source Nick Dall

Prior to any trip with altitudes in excess of 8,000 feet, Luna recommends making two medical appointments: one with a specialist travel doctor and another with your GP who’s familiar with your medical history. While AMS can affect people of all ages and fitness levels, some preexisting conditions (high blood pressure, sickle cell anemia, sleep apnea) can influence what drugs you’re prescribed and/or necessitate a change in itinerary. “In some cases,” says Luna, “we wonder, why did this man even try this hike?”

 If you don’t bother to see a doctor beforehand and end up feeling rubbish once you arrive, see a doctor. And avoid over-the-counter altitude medications, especially those containing caffeine, which can mask symptoms and accelerate dehydration.


You don’t have to be hiking to be affected by extreme altitude.

Source Nick Dall

When it comes to treating the symptoms, descending from altitude is always first prize — all the way down to sea level, if possible. Inhaling oxygen is another cornerstone of treatment, although Luna says the pocket-sized canisters you can buy in airports and curio shops are an expensive gimmick: “In our experience, you need to inhale oxygen for at least 30 minutes to feel the effects.” Fortunately, oxygen is readily available at clinics and hospitals in high-altitude regions, and experienced guides like Vargas never trek without a tank. “On the trail, oxygen can save your life,” explains Luna. 

But the wonders of modern medicine mean that it should never even get to this. Make those doctors’ appointments before you go. And actually do what you’re told — even if it means changing your plans. The Inca Trail is awesome, but it’s not worth dying for. 

(Chewing coca leaves, on the other hand, is not remotely awesome. Unless you’re in the habit of munching on garden hedges.)

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A packhorse enjoys a well-deserved rest just outside Mollebamba.

Source Nick Dall


  • Headaches
  • Nausea and vomiting
  • Lack of appetite
  • Fatigue
  • Insomnia (this is often missed)
  • Bluish lips and fingernails (one of the first signs of HAPE)
  • Dizziness with slurred speech and clumsy movements (HAPE is setting in) 
High altitude illness explained

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