Acclimatization & Altitude Sickness on Kilimanjaro: A Complete Guide

Altitude sickness is the primary reason climbers fail to reach the summit of Mount Kilimanjaro, affecting an estimated 50% to 77% of trekkers above 3,000 meters. Because Kilimanjaro rises to 5,895 meters (19,341 feet) over a relatively short period, the lower atmospheric pressure significantly reduces the amount of oxygen your body receives per breath. It can affect anyone—physical fitness, age, or gender do not make you immune to altitude illness.

Mount Kilimanjaro is the highest mountain on the African continent with a height of 5,895 meters (19,341 ft). Kilimanjaro has its own challenges, the most dangerous of which being altitude sickness. “At 9,000ft and above a large percentage of persons will have some symptoms related to altitude. Safety is our Number one priority at Climbing Kilimanjaro.

Effects of Altitude on Kilimanjaro

Kilimanjaro has become a very popular journey since it offers ordinary hikers a chance to reach a high mountain summit without needing any technical skills. Some individuals misjudge the potential for catastrophic, life-threatening events due to the altitude, what is known as a “walk-up” without the need for ropes and climbing gear.

Kilimanjaro’s summit is considered ‘extreme altitude’ as are Aconcagua and Denali (Mt McKinley). Everest and K2 are “ultra” altitude, where no acclimatisation is conceivable.

A Brief Introduction to Altitude

At the top of Kilimanjaro the air has around 49% less oxygen than at sea level. But it is not the percent of oxygen in the air that varies , it is the barometric pressure (air pressure) of the atmosphere that is changed .

The air still contains 20.9% oxygen, but because of the lower air pressure, it is not available in the same way. In layman’s words, this means that for each breath you take there are less oxygen molecules to be had.

There are other difficulties with the reduced air pressure too. Fluid pools outside the cells , around the brain (High Altitude Cerebral Oedema) and the lungs (High Altitude Pulmonary Oedema) which are both very hazardous disorders.

Altitude Sickness: What is it?

There are three major types of mountain sickness: Acute Mountain Sickness (AMS), High Altitude Cerebral Oedema (HACE) and High Altitude Pulmonary Oedema (HAPE). AMS can also be mild (quite common, manageable with the correct therapy), moderate and severe (descent right now).

Let’s look at these conditions more closely.

Acute Mountain Sickness

Anyone at over 6,000ft can be affected by AMS, says Dr. Peter Hackett of the Institute for Altitude Medicine. The first sign is usually a headache, which can confusingly also be a sign of dehydration or over-exertion. AMS is likely to be the diagnosis if further symptoms emerge.

Mild AMS

At its mildest the symptoms may be similar to those of a hangover with nausea, headache, exhaustion and loss of appetite. If you feel any of these symptoms it’s vital to tell your guide and not just try to push through. Mild symptoms generally get better with rest and appropriate fluid intake.

Moderate AMS

If the symptoms of mild AMS start to worsen, headache that you can’t shake, dizziness, coughing, shortness of breath, nausea and vomiting, this is an indication you are not acclimating to the altitude and at this point you should descend to the last elevation you felt “well”.

Medications such as ibuprofen for the headache or anti-emetics for the nausea can conceal worsening symptoms and should not be used as a reason to continue the ascent.

Severe AMS

If a person with moderate AMS ignores the symptoms and continues to a greater altitude, the condition may worsen. If severe, AMS can develop to life-threatening consequences (HAPE and HACE) for which quick descent is required.

Symptoms are severe headache, ataxia (loss of co-ordination, inability to walk properly, staggering), increased coughing, shortness of breath. If you get a bad case of AMS you will most likely have to be evacuated from the mountain on a stretcher or helicopter.

Severe mountain sickness can lead to complications, including HAPE and HACE.

High Altitude Pulmonary Edema (HAPE)

Basecamp MD explains that HAPE can develop as a result of the lung arteries developing excessive pressure as a result of the low oxygen environment. This pressure causes build up of fluid around the lungs.

Confusingly, it’s possible for a climber to develop HAPE even if they don’t seem to have symptoms of severe AMS.

Look out for:

  • Coughing up blood or mucus
  • Abnormal lung sounds
  • Extreme listlessness
  • Difficulty breathing
  • Lips going blue
  • Confusion, lack of coordination
  • Anyone at altitude who feels as though they have a respiratory infection should assume it’s HAPE until a medical professional proves it to be otherwise. If HAPE is suspected, oxygen is often administered in conjunction with immediate evacuation to a medical facility.

As oxygen levels in the blood drop, the brain can suffer from lack of oxygen, leading to HACE.

High Altitude Cerebral Edema

HACE is a very dangerous condition that requires immediate medical treatment. As fluid builds up around the brain, the climber comes increasingly confused, lethargic and drowsy, incapable of walking and behaving strangely.

Look out for:

  • Disorientation, confusion, hallucinations, talking nonsense
  • Lack of coordination, staggering, inability to walk
  • Irrational behavior
  • Severe headache, sometimes accompanied by nausea and vomiting
  • HACE cannot be treated without immediate evacuation to a medical facility.

How is Altitude Sickness Diagnosed?

In our daily health checks, Climbing Kilimanjaro guides will use a pulse oximeter to measure your oxygen saturation and pulse rate and use this data along with any symptoms you are presenting to build up a picture of your situation.

Lake Louise Scoring System

Developed in 1991 and reviewed as recently as 2018, the Lake Louise Scoring System remains the basis for most diagnosis in the field of a climber’s condition. Climbing Kilimanjaro guides use this as a framework when they assess your condition. The ‘score’ attaches a number depending on the severity of your condition.

Headache

  • 0—None at all
  • 1—A mild headache
  • 2—Moderate headache
  • 3—Severe headache, incapacitating

Gastrointestinal symptoms

  • 0—Good appetite
  • 1—Poor appetite or nausea
  • 2—Moderate nausea or vomiting
  • 3—Severe nausea and vomiting, incapacitating

Fatigue and/or weakness

  • 0—Not tired or weak
  • 1—Mild fatigue/weakness
  • 2—Moderate fatigue/weakness
  • 3—Severe fatigue/weakness, incapacitating

Dizziness/light-headedness

  • 0—No dizziness/light-headedness
  • 1—Mild dizziness/light-headedness
  • 2—Moderate dizziness/light-headedness
  • 3—Severe dizziness/light-headedness, incapacitating

AMS Clinical Functional Score

Overall, if you had AMS symptoms, how did they affect your activities?

  • 0—Not at all
  • 1—Symptoms present, but did not force any change in activity or itinerary
  • 2—My symptoms forced me to stop the ascent or to go down on my own power
  • 3—Had to be evacuated to a lower altitude