Effects of altitude on Kilimanjaro
Kilimanjaro safety tips and effects of high altitude


Effects of altitude on Kilimanjaro

So you are looking at climbing Kilimanjaro but are worried about what will happen to your body at altitude?

We have been involved in mountaineering not only on Kilimanjaro but on some of the highest mountains the in the world for over 20 years. We have been in countless situations at altitude and have not only helped people through these situations but have also got to experience some of these effects ourselves.  It is one thing to help a climber with a Pulmonary Edema from an outsider’s perspective, but having suffered one myself I can really appreciate the emotional trauma that clients go through.

This article is dedicated to giving you a down to earth description of the effects of altitude on your body. We are not only going to approach the subject from a scientific point of view but also from an experience point of view. Over the years we have compiled statistics from our clients at various altitudes and have determined a guide to where they should be physically at those altitudes.  There are various daily criteria that need to be met while on the trek to climb Kilimanjaro safely. We will discuss our ‘High Altitude Scoring Policy’ later in this article. But first we want to introduce you to the 3 main areas of concern to us as guides on Kilimanjaro.

What happens to your body at altitude?

As you ascend into the thinning air, your body needs to produce more red blood cells. These cells are responsible for carting oxygen around your body. Makes sense that your body needs to produce more of them at altitude. But this process is slow. It takes time for your body to churn these oxygen seeking suckers out. What is the solution? To walk very slowly. In fact this is probably the main reason fit and competitive people suffer at altitude. They don’t listen to guide and ascend too quickly. The result is acute mountain sickness. Another factor is the dry air. This means that you are going to dehydrate a lot faster than at sea level. The recommended intake of fluid every day on Kilimanjaro is 5 liters. And onc again, prevention is better than cure. Try and pace yourself. Have 250ml every half an hour. Treating dehydration at altitude is not fun and in extreme cases the only way is to through an intravenous saline solution.

1) High Altitude Pulmonary Edema (HAPE)

What is a Pulmonary Edema in layman’s terms?

Okay, so some basic school biology is needed here. Basically what happens with breathing is that oxygen and carbon dioxide is transferred in the blood and is transferred by the process of osmosis through the arteries into the alveolar sacs in the lungs. As a hiker climber to a higher altitude, not only does the percentage of oxygen molecules in the air get less but the arteries also become constricted due to the changes in pressure. What basically happens with a Pulmonary Edema is that the lungs become starved of oxygen molecules and the result is that the plasma pulls through the artery walls into the alveolar sacs.  If left untreated, the lungs will basically fill up with plasma and the climber will ‘drown’.

What are the chances of getting a Pulmonary Edema?

According the latest statistics, the chances of getting a Pulmonary Edema on Kilimanjaro is between 2-4 %. Now if you ask me, those are pretty good stats and shouldn’t prevent you from climbing. As with any form of sport or adventure activity, knowing what the chances of dying are vital in the decision making process. If you are willing to accept the odds then you are ready to climb.

Preventing a Pulmonary Edema on Kilimanjaro

So now that we have covered the odds of you getting an Edema at altitude, let’s focus on how we manage the percentage of people that may be susceptible to it. In mountaineering, prevention is better than cure. Period.  On all of our Kilimanjaro climbs, our guides perform recorded medicals on hikers 3 times a day.  Our primary concern is to focus on any preliminary signs of a Pulmonary or Cerebral Edemas.  The tests include an oxygen saturation reading using an oxymeter as well as listening to the lungs with a stethoscope for the ‘gurgling’ sounds of a pulmonary edema.  As mentioned, we have set benchmarks at the various altitudes where we require climbers to be in terms of their saturation levels. For example; at an altitude of 3000m, the average saturation level should be between 94 and 96%. If a hiker ha a reading of 89%, we are going to be concerned. A lower saturation level means that the lungs are not getting adequate oxygen.  Sometimes it may be a timing thing which we allow for. Some climbers acclimatize slower than others.  That is why we check 3 times a day. If there is no improvement as the day continues, we can make a logical decision on whether it is safe to continue or not.


Never ever climb if you have a chest infection, bronchitis or any other chest related illnesses. A cough at sea level can be deadly at altitude. You will need to be open and honest with yourself and your guide. You will drastically increase your chances of getting a pulmonary edema is you climb while sick. In case studies of people who have died on Kilimanjaro, the majority of them had pre-existing conditions before they started the climb. Yes it may mean you lose a lot of money or have to give up on a dream, but your life is way more important than a mountain.

Medication available to prevent Pulmonary Edemas

There are 2 types of medication available that can prove useful in the prevention of Pulmonary Edemas at altitude.

The first is Diamox: This drug is basically a diuretic and ‘pulls’ the plasma from your lungs thus preventing them from filling up.

The second is Viagra: This drug helps to keep the arteries rigid allowing for the transfusion of oxygen molecules into the lungs.

What we do when there are signs of a pulmonary Edema  in a climber on Kilimanjaro

As soon as we suspect a pulmonary edema, we administer oxygen and depending on the severity of the hiker, we make use of a Gamow bag to simulate a lower altitude. A dosage of Viagra is also used to ‘buy’ us time. Our main priority is to get the patient down to a lower altitude as quickly as possible.  The effects of the Edema will lessen dramatically even from a mere 500m drop in altitude in most cases.

2) High Altitude Cerebral Edema (HACE)

What is a high altitude cerebral Edema in layman’s terms?

Basically it is the swelling of the brain with fluid due to the physiological changes at altitude. The diagnosis is not as easy as the pulmonary edema. Some of the more common signs include dizziness, lethargy, disorientation and a severe pounding headache at the base of the skull.

Preventing a Cerebral Edema on Kilimanjaro

As mentioned we perform medicals 3 times a day on our climbers. We make use of the Lake Louise Altitude Scoring Sheet. This method basically gets clients to rate certain questions on a scaling system, focusing on the whereabouts of headaches, severity, and other mental cognitive tests. If we suspect any irregularities, we err on the side of safety and will get the hiker down as soon as possible. A dose of dexamethasone is given which prevents the brain from swelling and buys us time to get the climber to a lower altitude.

What we do when there are signs of a Cerebral Edema  in a climber on Kilimanjaro

A lot of climbers come to us complaining of a headache. A lot of the time, the headache is not necessarily a threat. Dehydration for example can contribute to a headache. Sinus pain due to the dry air or sore neck muscles from sleeping funny also may contribute to a headache. With dehydration induced headaches, usually a good rehydrate and a couple of Iboprufens seem to help. Obviously if they don’t we may take our concern levels to another level and monitor the degree of pain.  As soon as we suspect a HACE, we administer d dexamethasone and get the patient to a lower altitude as quickly as possible.

What are the chances of getting a Cerebral Edema?

As with the HAPE, the chances are between 3-5%


About Author

Adventure enthusiast, Safari expert & overall a happy guy. I love Trekking and Hiking , especially summiting Kilimanjaro. I have a passion for people, animals and the beauty of nature


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