Welcome to next level trekking and goodbye to knowing the limits of your body. At high altitude these will be redefined – especially if it’s your first time. You may even find out that trekking above a certain altitude is not for you. But that's alright. You’re here for the challenge.

A note before you continue reading: Inform yourself well before you consider trekking at high altitude. Consult a doctor if you have any medical conditions (i.e. heart conditions, diabetes, high blood pressure, etc.) or have experienced health problems before. Reading this post is not a guarantee as it is based on personal experience and the bit of knowledge I can provide.


Abra Palomani at 5200m: A pass I crossed while doing the Ausangate Circuito (you can see glimpses of Vinicunca / Montaña de Siete Colores in the background)


From scratch: What is high altitude?

In addition to the previous paragraph, a few more words on reacting to higher elevation.

It’s very important to know that everybody reacts differently. Just because your friends cope well with higher altitudes, doesn’t mean that you will. Even though they may have the same fitness level or even less than you. Fitness can be a positive contributor. Still, it’s not a given that, as an example, someone who’s a badass marathon runner at lower levels is going to be fine.

I’m a runner and one of the biggest issues for me when going up to higher altitude was to handle my breath. Or the lack of it, so to say. I wasn’t used to being out of breath just by walking moderately. So this was a bit of a freaky feeling at first causing me to be a bit anxious and even more out of breath, yada yada. An interesting mental challenge for me.

That said, everybody can get altitude sick or will most likely feel at least mild symptoms, depending on the altitude. Our bodies adjust up to a certain point. But even if someone has been to high altitude before, the same person may get sick when returning back to the same elevation again later in life.

At around 2,500m of elevation the air starts becoming significantly “thinner”. I describe what this means in the next section. It’s helpful to be aware of the following levels:

  • 2,500m – 3,500m
  • 3,500m – 5,500m → The guide who I was climbing a 6,000er with told me that, from his experience, around 5,500m symptoms might kick in, even with people who were doing fine until then.
  • Above 5,500m
  • Anything above 8,000m is considered the death zone as the amount of oxygen per breath makes human life for an extended time period impossible.

Use this as a guideline. The values might slightly differ in exact number depending on the source they’re from.

What happens at high altitude?

The concentration of oxygen in the air is around 21%. This number is the same at sea level as well as at higher altitude. What changes when reaching higher elevation levels is the barometric pressure. It decreases. This means oxygen molecules are further apart which ultimately results in less oxygen in the amount of air one inhales with each breath.

Less oxygen in your breath is less oxygen transported to the muscles of your body. This ultimately leads to limited performance.

The higher you get, the more your body has to work just to keep you standing and "function" (somewhat) properly. This requires more energy input. Still, a lot of people tend to eat less at high altitude as suppression of appetite is a pretty common symptom.

Fluid loss increases with altitude.

Simultaneously, the body is working on adjusting to these new conditions. One way to do so, is by producing more red blood cells as these will be able to carry more oxygen. I find this incredibly fascinating.

It's also one of the reasons why you’ll feel like a superhero when returning to sea level or lower altitudes after spending a longer period of time at high altitude. Especially being an athlete who continues regular exercise and training when going up.

At the beginning, my runs between 3,500m and 4,500m of elevation felt like I’ve never run before in my entire life AND smoked a pack of cigarettes before doing the runs. The ones I did just after returning to sea level felt like a walk in the park. Despite longer distances at much higher speed.

Another word on running or doing any exercise at high altitude...

If you’re used to regular running activity and plan to continue this at high altitude: Always take it easy and really listen to your body. Especially in the beginning, you won't be able to perform the same way you're used to. No matter how fit you are. No matter how many long distances, (ultra-) marathons, you’ve run before.

I ran my usual times and distances at 2,500m without any issues. My first run at 4,500m, on the other hand, was just a couple kilometers at a time, going super slow.

The process of adjusting to high altitude is called acclimatisation. Keep in mind, this doesn’t happen within minutes. Acclimatisation may take days. More on this in the next section.


Enjoying the company of some acclimatised llamas :P



The most common mistake, especially inexperienced, hikers make is not giving themselves enough time to adjust to the conditions of high altitude. Tourism has become a common at high altitude. Even Mt. Everest has become a tourist destination. With tourism always seems to come a challenge of time. How to get the most out of something in a limited amount of time. There may be people out there who tell you differently but acclimatisation is not something you can force. If you don’t have time to properly acclimatise, don’t do trekking at high altitude. It’s that simple.

Usually, it takes between 1-3 days to adjust to a level of altitude. It really depends on each individual. Be aware, adjustment doesn’t take place once but every time you go higher in elevation. This is specifically important for multi day tracks. You could be fine when going to bed and wake up feeling unwell as symptoms tend to get worse overnight when gone too high too quickly.

If you experience symptoms, even just mild ones, take a rest, don’t go higher and give yourself time to adjust. If symptoms get worse and don’t decrease, you need to go down. Once you’re experiencing severe symptoms, going back to lower elevation is the only solution.


Mild symptoms can be:

  • headache
  • nausea
  • slight dizziness
  • fatigue
  • shortness of breath
  • faster heart rate
  • trouble sleeping
  • loss of appetite
  • nose bleeding

Going higher with these symptoms can be possible but only if they don’t get worse, decrease or, at least, stay mild. It depends on the group you are with, the level of your experience and capability to judge how far you can go.

Something to be aware of: Just because high altitude tracks and summits are becoming more and more accessible to inexperienced hikers/mountaineers does not make effects these altitudes can have magically disappear - or some of the routes any less dangerous.

Severe symptoms can be:

  • everything in the list of mild symptoms but much worse
  • vomiting
  • unstoppable cough
  • out of breath, even when resting
  • inability to walk
  • decreasing mental state
  • fluid build up in lungs

If you experience any of those: Down, down, down!


I’ve summarised a list of guidelines below. These have been very useful to not only me but people of the groups I’ve done high altitude trekking with. Hopefully they serve you well.

  • Climb high, sleep low. This means: Sleep lower than the highest point of the day. This is to get your body used to higher altitude and give time to adjust overnight rather than overwhelming yourself. Try to avoid sleeping higher than 300m within one day. You can hike higher than that, as long as you feel well, but should aim for a campsite on a lower level.
  • Don’t fly or drive to high altitude as it’s too fast for the body to properly adjust. If you do, spend enough time at that altitude to adjust before going higher.
  • Water, water, water! I’m not talking about half a liter per day here. Try to aim for at least 2-3l a day. I always go for at least 4l as I’m used to drinking a lot.
  • Try to avoid eating red meat or milk products. In general, you want to avoid any foods that challenge your digestive system. This takes energy away from adjusting to the altitude.
  • Eat lots of carbohydrates. I’ve mentioned right at the beginning that the higher you get the more energy is needed for your body just to function “as usual”. Aim for roughly 70% from carbs. A good example and source of carbs is quinoa, especially when hiking in the Andes. Needles to say, that you should still try to keep it healthy.
  • Avoid alcohol and tobacco.
  • Increase your iron intake. As mentioned above, one of the ways your body will adjust is by producing more red blood cells. More red blood cells → more iron necessary.
  • A good source of iron are coca leaves. But that’s only one reason why they help to cope with high altitude. I dedicated the next section to coca leaves. So, you’ll find some more information there.
  • Avoid sleeping pills or other tranquillizers.

As a general guideline: Don’t do anything that gives your body more work than necessary. Your body being you. At high altitude you work under high stress, just keeping alive and standing. Maybe even without realising so. Anything on top of that is more work resulting in quicker exhaustion shown in symptoms as mentioned above.

Another important thing is to always watch out for ALL members of the group you’re trekking with! No peak, no track, no ego is worth another being’s life. Only keep going when all group members have adjusted to higher altitude.

Below you’ll find an extra section on coca leaves. They are an important part in Andean culture. As my experiences at high altitude so far have been deeply connected to Andean culture, I simply can’t write an article on high altitude trekking without providing this little extra.


Huayna Potosí at 6080m: Often referred to as the "easiest 6000er in the world" it causes many inexperienced hikers to underestimate the altitude. Always respect the mountain...


An extra on Coca Leaves

I spent a few months at high altitude doing trekking in Peru in 2019. Coca leaves are part of Andean culture and common to use to cope better with high altitude. They were one of the major crops and deeply implemented in Inca culture.

As they are the main ingredient to a hard drug, their cultivation is now prohibited in a lot of countries. Peru is one of the countries, where it’s still legal to cultivate them.

I’m dedicating an extra section to coca leaves because there seems to be a bit of confusion out there. Lots of people, especially from western countries, think coca leaves automatically equal cocaine. That is not the case.

The major demand for cocaine as a drug has been coming from western countries, such as USA, UK, Australia, European nations. Prohibiting the cultivation of coca leaves in South American countries does not only take focus away from the actual issue but also steals a part of culture from indigenous people.

Yes, coca leaves are the main ingredient for cocaine. But: There’s long ways to go for a coca leave to become cocaine. This process also includes gasoline. So, no coca leaves aren’t the same as cocaine.

The plant itself is highly nutritious, containing minerals, vitamins, even fibre and protein. I’ve already mentioned the advantages of its high amounts of iron in the paragraphs above.

Opposite to cocaine, the leaves are said to not be addictive nor have any negative side effects.

Coca leaves suppress fatigue, hunger and thirst. They may also increase metabolism and heart rate.

There are different ways of consumption. I preferred coca leaves with boiled water as tea with honey. I was primarily drinking it for the taste and the effect of keeping me warm while trekking. Effects differ individually. I’ve watched coca tea do little wonders to people who were suffering from fatigue and headaches at high altitude.

Another way of consumption is chewing. You take a bunch of leaves, remove the stems and put them inside one of your cheeks. Additionally, something I’ve got to know under the name cal can be used to activate the coca while chewing. Another name for this is lejía. If used, this is rubbed into the leaves kept in your cheek. It’s sweet flavoured ash.

An example for coca leaves being part of a Quechua ceremony is la Ofrenda a la Pachamama. Pachamama is Mother Earth. The ceremony is about giving back to Her what was taken and ensure a balance between nature and human being.


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