At 19,341ft, Kilimanjaro presents a unique set of challenges, the most dangerous of which being altitude sickness. A significant proportion of people who climb over 9,000ft develop some symptoms relating to altitude.
Kilimanjaro has become a very popular trek as it’s a way for ordinary hikers to experience a high mountain summit with no technical skill. Being what’s known as a “walk-up”, without the need for ropes and climbing gear, some people underestimate the potential for serious, life-threatening situations as a result of the altitude.
Kilimanjaro’s summit falls into the “extreme altitude” category, along with Aconcagua and Denali (Mt McKinley). Everest and K2 are “ultra” altitude, where acclimatization is impossible.
At the summit of Kilimanjaro there is approximately 49% less oxygen than at sea level. However, it’s not the percentage of oxygen in the air that changes, it’s the barometric pressure (air pressure) of the atmosphere that’s reduced.
The percentage of oxygen in the air is the same 20.9%, but it’s availability is reduced by the reduction in air pressure. What this means, in simple terms is that for any volume of air you breathe in, there are less molecules of oxygen available.
The reduced air pressure has other problems associated with it as well, allowing fluid to collect outside of the cells, around the brain (High Altitude Cerebral Edema) and the lungs (High Altitude Pulmonary Edema), both very serious conditions.
Mountain sickness has three main forms: Acute Mountain Sickness (AMS), High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE). Additionally, AMS can be mild (very common and manageable with the right treatment), moderate, and severe (immediate descent necessary).
Let’s take a closer look at these conditions.
According to Dr. Peter Hackett of the Institute for Altitude Medicine, AMS can affect anyone above 6,000ft. The initial sign is usually a headache, which confusingly can also be a sign of dehydration or over-exertion. If other symptoms develop, then a diagnosis of AMS is probable.
In it’s mildest form, the symptoms can resemble that of a hangover, with nausea, headache, fatigue, and a loss of appetite. If you experience any of these symptoms it’s important to tell your guide and not simply try to push through. Mild symptoms can often be resolved with rest and adequate hydration.
If the symptoms of mild AMS start to get worse, a headache that you can’t shift, dizziness, coughing, shortness of breath, nausea and vomiting this is an indication that you are not adapting to the altitude (acclimatizing) and at this point you should descend to the last elevation that you felt “well”.
Treatments such as ibuprofen for the headache or anti-emetics for the nausea can mask worsening symptoms and should not be relied upon for continued ascent.
If a person suffering with moderate AMS ignores the symptoms pushing through to a higher elevation, there’s a risk that the condition can become severe. Severe AMS can lead to life-threatening complications (HAPE and HACE) and immediate descent is mandatory.
Symptoms can include severe headache, ataxia (lack of co-ordination, inability to walk properly, staggering), increased coughing and shortness of breath. Someone with severe AMS will likely need evacuation from the mountain either by stretcher or helicopter.
Complications resulting from severe mountain sickness are HAPE and HACE.
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:
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.
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:
HACE cannot be treated without immediate evacuation to a medical facility.
In our daily health checks, our 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.
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. Our guides use this as a framework when they assess your condition. The ‘score’ attaches a number depending on the severity of your condition.
0—None at all
1—A mild headache
3—Severe headache, incapacitating
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
3—Severe fatigue/weakness, incapacitating
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
[Source: High Altitude Medicine and Biology]
The term acclimatization or “acclimation” refers to the body’s compensatory processes to adapt to the low-oxygen, low-atmospheric pressure environment. From day one, your body will start to make adaptive changes to compensate.
Things you’ll notice:
As you ascend slowly, your body has certain mechanisms it uses to adapt:
All of these changes are a gradual process, which is why the best and safest summit success rates are had on routes with a good acclimatization protocol. The longer it takes to reach high altitude, the longer your body has to adapt.
By building in acclimatization days “hike high, sleep low” and rest days increases your chances of adequate adaptation, resulting in lower incidence of mountain sickness.
Acclimatization is a complicated process, some people seem to have no problem at all. There are no tricks or hacks, it’s a matter of time, although the medication Diamox has been shown to up regulate the body’s natural acclimatization processes and can help speed it up.
Altitude Training is becoming increasingly popular amongst would-be mountaineers. Some athletes use these training protocols to enhance performance, and studies have shown a “pre-acclimatization” process as a result.
The protocols vary from training in a simulated altitude chamber, sleeping in a hypoxic tent, and even intermittent exposure to hypoxic air at rest. You can read our in depth guide to altitude training for more information.
The best pre-acclimatization method would be to climb Mt Meru, or some peaks in your home country prior to traveling to Kilimanjaro. This isn’t possible for everyone, nor is it necessary but if you do have access to some high altitude you’ll get a good idea of how well you acclimatize.
Your doctor will advise you of whether your medical history prevents you from traveling to altitude. Many people with well-controlled pre-existing conditions are able to climb Kilimanjaro successfully.
Anyone with heart, lung or neurological conditions will need to have a medical sign-off from their doctor before joining one of our climbs. It’s particularly important for your doctor to assess how the altitude may affect your current medications and condition. Be aware that certain medical conditions may make getting adequate travel insurance more difficult.
One of the main reasons for sleep disturbance at altitude is periodic breathing. This is not necessarily associated with altitude sickness, but can be uncomfortable and disruptive. The Institute for Altitude Medicine explains that it’s a “battle in the body over control of breathing during sleep”. The oxygen sensors tell the parasympathetic nervous system to breathe more deeply, whilst the carbon dioxide sensors tell it to stop.
The result is usually deep breathing followed by the breathing stopping, and then a deep-breath as it restarts. Diamox often helps with this condition.
While altitude sickness is the main concern, you need to take a pro-active view of your health whilst climbing.
Never stay in wet clothes. Whether from rainfall or perspiration, once you stop moving, a slight chill can turn to hypothermia in a short time, especially higher up the mountain. Make sure you carry adequate layers in your daypack, as rapid changes in temperature are quite common as you ascend.
Always wear sunscreen, preferably factor 40+, cover exposed parts of your body, including your head and neck. As you ascend, there is less atmosphere to filter out the harmful UV rays, and the sun’s rays are harsh.
Most importantly, wear sunglasses that block 100% of the UV rays. Wraparound glasses are best, to prevent reflected UV off glaciers and snow from damaging your eyes. Snow blindness is not common, but it’s a definite risk if you don’t protect your eyes.
Any travel to remote places comes with a risk of gastro-intestinal trouble. Different foods, sub-standard hygiene, and exposure to bacteria and viruses can cause stomach problems. Always use anti-bacterial gel or wipes on your hands, especially before eating.
Your main risk for stomach trouble is before your climb. Avoid eating at street stalls, stay away from tap water, salads, and fruit you can’t peel. On the mountain we adhere to strict food hygiene protocols and provide safe purified water at all times.
We take your safety very seriously. Our trained guides will monitor you closely, but to do that, they also need your help. If you feel in any way unwell, you should inform your guide immediately. Keep an eye on other members of your group, if you see someone behaving strangely or they appear to be suffering, tell your guide.
Every day your guide will check your oxygen saturation with a pulse oximeter, question you about how you are feeling, and listen to your chest for unusual lung sounds. Catching it early is the best way to prevent mild altitude sickness escalating.
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