You have your heart set on climbing Kilimanjaro. You have done your research and booked with a reputable operator. As you were doing your research one thing that kept coming up was acclimatization. You are in good shape, but how can you train for the high elevation?

First of all, what exactly is acclimatization? Acclimatization is best understood by looking at the relationship between oxygen in the air, air density and altitude changes.

At sea level oxygen accounts for about 21% of air and the barometric pressure is around 760 mmHg (milliliters of mercury) or 1 atm (atmosphere). As you climb the mountain the amount of oxygen in the air remains about the same up to approximately 69,000 ft. (21,000m). However, as the air density drops there is now less pressure packing the oxygen molecules together. In short, the molecules are now moving farther apart.

Let’s say for example, at about 12,000 ft (3,600 m) the barometric pressure is around 480 mmHg (.63 atm). With less air density the oxygen molecules are more widely dispersed in any given amount of air and hence less oxygen is available per breath.

Kilimanjaro Altitude Zones

During your climb of Mount Kilimanjaro, you will pass through three altitude zones. These zones are; high altitude 8,200 ft – 11,400 ft  (2,500 – 3,500m), very high altitude 11,400 ft – 18,000 ft  (3,500 – 5,500m) and extreme altitude above 18,000 ft (5,500m).

Most people can ascend to 7,800 ft (2,400 m) without experiencing the effects of high altitude. However, as a person enters the high altitude zone these changes in air density and thus the amount of available oxygen begins to take effect.

How each person reacts to this change in oxygen saturation is unpredictable. It is not altered by the fitness level of the climber. It can also change by the day and by elevation. What effects a person one day may not affect them at all the very next day, week or month. There is also no correlation between age and gender.

One thing we do know is that ascending too quickly in elevation is a key cause of Acute Mountain Sickness (AMS). Other contributing factors are overexertion and dehydration.

Our guides, want to make sure you make it to Uhuru Peak, after all, that is the reason you flew all this way. To make sure this happens, a proper acclimatization strategy involves not going too high, too fast. And by not over doing it each day while attempting to summit. That is also why they tell you “sippy, sippy” to remind you to drink your water. And “pole, pole” so you don’t hike too fast.

To expand on this point, we will further discuss what is called Acclimatization Line.

Acclimatization Line

The term Acclimatization Line is used to describe the point where someone’s altitude sickness symptoms begin to occur.

Let’s say, for instance, a person’s acclimatization line is 15,150 ft on day one. After trekking to this height and spending a night or two there, the body would acclimatize to that altitude and that person’s line might move to 17,500 ft. If they then descend to 15,150 ft they will remain asymptomatic, but if they climb to 18,000 ft they would begin to experience altitude sickness symptoms.

The body can adjust to these elevations by spending additional time at an elevation or by dropping down and ascending to it again. If a person continues to ascend beyond their acclimatization line it is almost guaranteed that symptoms will worsen and further acclimatization will not occur. It is critical that one gets below the point where symptoms began in order to see improvement. That is why we use the climb high and sleep low approach whenever possible as you climb Mt. Kilimanjaro.

Once you have these symptoms it is imperative that to pay attention to them. You cannot just tough it out. Our guides have been trained to recognize these symptoms and will take you back down to an elevation that is safe for you.

The body does adapt to higher altitudes

Here’s the good news, your body is very good at adapting to changes in its environment. Given enough time your body can adapt to high altitude.

Below are four things that occur as you ascend.

1. Your breathing will become faster and you will breath deeper.

2. Your bodies red blood cell count will increases which allows more oxygen to be carried in the blood

3. The pressure in your pulmonary capillaries will increase which will force blood into areas of the lungs that are not used while breathing at sea level.

4. More of a particular enzyme is produced which causes oxygen to be released from hemoglobin to the blood tissue

It is important to remember that your body can cope at altitude, it just needs time to acclimate.

Symptoms of Acute Mountain Sickness (AMS)

What are the symptoms you should watch out for? Keep in mind, most people will have a mild reaction to elevation. They may experience some of the following symptoms: a headache, stomach ache, bloating, dizziness and fatigue. This is normal. It is when they become severe that emergency procedures may need to be implemented.

What are the symptoms of AMS?

  • Headache: Throbbing, it gets worse during the night and when you wake up.
  • Loss of Appetite: No desire to eat or drink
  • Nausea: Feeling sick to your stomach, you may also vomit.
  • Lethargic: Feeling weak and tired. In severe cases, you do not have the energy to eat, dress, or do anything.
  • Insomnia: Waking up constantly during the night or not sleeping at all.
  • Dizziness: You may feel dizzy and disoriented.

If you feel the onset of any of these symptoms or your mild symptoms worsen, let your guide know. Chances are he will already know and will have you take a break, drink water and eat. Worse case, he would have you cease your summit attempt and escort you down to a safer elevation.


Our safety procedures begin well before a client steps foot on the mountain. We began by finding and hiring the best, most accomplished, experienced Kilimanjaro guides. Our guides are certified Wilderness First Responders. Our climbs have a 1 to 2, guide-to-climber ratio. We also conduct daily health checks and use a pulse oximeter to measure your pulse and oxygen saturation throughout your climb. Our guides also carry emergency oxygen and we track our clients with the Garmin InReach GPS System.

In addition, we have partnered with IFREMMONT, a European high altitude medical training organization with the most qualified high altitude doctors in the world, to co-develop Kilimanjaro safety and rescue protocols. We cover all of our clients with AMREF Flying Doctors evacuation insurance so we could transport someone quickly via helicopter off the mountain and to the hospital in case of serious emergency. Clients may also rent ALTOX a personal oxygen system which reduces or eliminates the symptoms of altitude sickness.

In conclusion, climbing Kilimanjaro is not easy, it is something you need to prepare for. However, no matter how fit you are and how much you have prepared, you still may suffer from Acute Mountain Sickness. Our advice to you is as you climb Kilimanjaro, listen to your guides, drink plenty of water, walk slowly and climb with the best guides on Kilimanjaro.

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