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Testing Altitude Sickness in Peru

The first thing people mentioned when they heard I was going to spend some time in Peru was, "Aren't you worried about altitude sickness?" So I became interested in testing what happens to the body during the drastic changes in altitude associated with travel in Peru.

Machu Picchu - Testing Altitude Sickness

Dealing with Altitude in Peru

Millions of people visit Peru each year and most of them make a stop at Machu Picchu to experience one of the New 7 Wonders of the World. Nearly every international flight arrives in Lima, Peru which is on the coast of the Pacific Ocean at sea level. In order to visit Machu Picchu you must first fly (or take a very long bus ride) to Cusco, Peru. This is where the issues related to high elevations start to affect people. Cusco is 11,150 ft (3398m) above sea level. This means that a normal traveler will go from sea level to 11,150 ft in less than two hours - this can be very traumatic on the body.

What is Altitude Sickness?

Altitude sickness is the pathological effect caused by low partial pressure of oxygen at high altitudes. The amount of oxygen decreases as elevation increases. And, because our bodies require considerable amounts of oxygen to function, this decreased amount of oxygen causes people to experience a number of uncomfortable or painful or even deadly physiological responses.

Why is Oxygen Lower at High Altitudes?

Believe it or not, the air around us experiences the effects of gravity just like we do! Because air is pulled down toward the earth it is much more dense at the surface than it is at higher elevation (there is more air at lower elevations). This causes a high partial pressure of oxygen at sea level and the pressure and available oxygen decreases rapidly as elevation increases.

What are the Symptoms of Altitude Sickness?

The following are symptoms of mild to moderate acute mountain sickness (another name for altitude sickness) which the casual traveler in Peru might experience.

List provided by the National Library of Medicine.

  • Difficulty sleeping

  • Dizziness

  • Fatigue

  • Headache

  • Increased heart rate

  • Nausea

  • Loss of appetite

  • Shortness of breath

Severe acute mountain sickness can be deadly. Most travelers to Peru would not experience elevations that would lead to such extreme cases but it is up to you, the traveler, to know your own body, the symptoms, and possible effects of altitude.

Testing my Body's Response to Changes in Altitude​

I took an oximeter (find it here) to Peru to test my body's response to the rapid changes in elevation and kept the data as I traveled. In science it is important to have as much data as possible so I made the trip from Lima to Machu Picchu two times in two weeks because, like I tell my college and high school students - "More data is more better!"

The results of my changing heart rate and oxygen levels with altitude are below. Here is my simplified analysis of this two week journey:

  • As altitude increases, heart rate increases.

  • As altitude increases, oxygen levels decrease.

  • As oxygen levels decrease, heart rate increases.

One important outlier to notice is my heart rate at Machu Picchu during the first visit - it is incredibly high! I attribute this to the shear excitement of being able to live out one of my dreams - visiting Machu Picchu.​​

Is Coca Leaf and Coca Tea Safe?

People living at high altitude in the Andes have been chewing coca leaf and drinking coca tea for thousands of years to alleviate the symptoms associated with high altitude. However, most travelers are concerned about coca because of its association with cocaine. Cocaine is refined from the coca leaf but in massive quantities and coca tea (or chewing the coca leaf) offers the drinker a minimal amount of the organic coca alkaloid; this small amount acts as a mild stimulant having a similar effect to the caffeine in coffee. And, while there is little research exploring the physiological effects of coca, every user may feel different effects, including increased heart rate, ability to have greater exertion at high altitude and loss of headache at high altitude - just like any remedy, every user will experience a different effect. I can tell you from experience in Peru that consuming coca tea caused the following: my heart rate increased, my breathing became deeper and the haziness I was feeling in my head cleared up.

Is Coca Leaf and Coca Tea Legal?

Yes, it is legal in Peru. In fact, the Cusco airport had coca leaves available for free as we deplaned. Coca is not legal in most other countries and, according to many sources, consuming it could give you a positive reading on a cocaine drug test for a few days after consumption.

My Advise For Traveling in Peru

If you have the opportunity to visit Peru, don't pass it up because of the potential effects of altitude sickness. Instead, plan ahead and know your limitations. Exercise and hike frequently before you go. Take an oximeter (find one here) so you can monitor yourself, and so you can do your own experimentation! Drink the coca tea. The locals know best when it comes to remedies for altitude ailments. Relax, explore, and soak up every moment - Peru is one of the most spectacular places in the world and no sickness will ever change that.

Keep on Learning! ~Craig

How to deal with the altitude sickness at Machu Picchu


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