HIGH ALTITUDE SICKNESS/ACCLIMATIZATION

Acute Mountain Sickness abbreviated as AMS and also known as altitude sickness or altitude illness, and its severe variants including High Altitude Cerebral Edema or HACE and High Altitude Pulmonary Edema or HAPE are the biggest concerns related to higher altitudes and acclimatization in Mount Kilimanjaro.

The process by which our body immunizes itself against the depleting oxygen levels at higher altitudes is known as acclimatization. It can only be achieved by spending sufficient time at a certain altitude before ascending or descending further.

Oxygen, Air Density and Altitude

It is best understood by keeping in view the relationship between the triad: oxygen in the air, density of the air, and change in the altitude.

At sea level, oxygen comprise of 21% of the air and the biometric pressure stands at about 760 mmHg (millimeters of Mercury). As one climbs higher, even if the oxygen in the air remains the same up to approximately 21,000 meters or 69000 feet, the air density drops significantly and less pressure is put on packing oxygen molecules which are closer together. (Put it another way, the oxygen molecules move further apart from each other as altitude increases).

The barometric pressure drops to about 480 mmHg at 3,600 meters (12,000 feet). This allows the oxygen molecule to get dispersed widely. Subsequently, less oxygen is available per breath.

Blood Oxygen Saturation

To counter the effect, our breathing rate becomes faster and deeper (even at rest) to compensate for the lower intake of oxygen per breath.

The chart below provides an estimate of the oxygen saturation level of an average person’s blood as he/she climbs to higher altitudes. Any average person’s blood oxygen saturation (SO2) would decrease to nearly 80% when they reach 6,000 meter, which is just above Kilimanjaro’s summit.

Kilimanjaro Altitude Zones

Kilimanjaro comprises of three altitude zones. These are: high altitude (2,500 to 3,500 meters), very high altitude (3,500 to 5,500 meters), and extreme altitude (beyond 5,500 meters).

Ascend to 2,400 meters won’t cause any negative implications for a normal being. However, as one goes past that level and enters the high altitude zone, the physiology of the person changes due to changes in air density and reduced available oxygen.

It is also difficult to predict the changes one may undergo at these level as there is very little for correlating to factors of gender, age, and fitness.

But one thing that’s certain is that going too high, too fast is the main reason climbers develop AMS. Other factors that contribute to the cause are dehydration and over exertion at higher levels.

Not ascending too fast too soon, ensuring you’re not overexerting yourself, and you’re hydrated all the time are signs of a well-planned acclimatization strategy.

Acclimatization line is a term used by climbers which is worth thinking about to illustrate this point.

Acclimatization Line

It is used to describe a particular point at which one starts to experience altitude sickness symptoms. For example, let’s have a person’s acclimatization line set at 3,000 meters on day one. After trekking to this height and spending one or two nights in this altitude, the body properly acclimatizes itself and the acclimatization line might move to 3,500 or so meters. Ascending further, if they climb to 3,400 meters, they’ll be free from any AMS symptoms, but beyond that, things will start to complicate.

If one remains near the acclimatization line, the body will keep adjusting itself. As you spend some time at the same level, the symptoms will gradually fade away and you’ll be acclimatized. But if one keep ascending beyond the line without making a brief stop at the line, the conditions are guaranteed to get worsen which will hinder further acclimatization. To have a successful trek, it is important to get below the point where symptoms begin to see improvement.

The last point illustrates the fact why it is deemed dangerous to ascend with symptoms of altitude sickness.

How The Body Adapts To Higher Altitudes

The good news is that our body performs really well at adapting to changing conditions. We just have to provide it enough time to adapt to the changes at the higher altitudes. Four main changes in body are worth a mention. As you ascend:

  • 1. There’s an increase in breathing rate and deepening of breath.
  • 2. There’s an increase in Red blood cell count which enables more oxygen content to be carried into the bloodstream.
  • 3. There’s also an increase in your pulmonary capillaries which forces blood into areas of the lungs that remain unused when you’re breathing at sea level.
  • 4. Enzymes of a particular kind are produced which cause oxygen to be released from the hemoglobin to the blood tissue.
  • It is important to remember that your body can cope at altitude, it just needs time to acclimatize.

Acute Mountain Sickness which is also known as altitude sickness or altitude illness is a pathological effect experienced by trekkers when they ascend to a higher altitude with lower levels of oxygen too fast.

  • People normally start to experience symptoms of AMS when they cross 10,000 feet.
  • Unfortunately, AMS is quite common among trekkers and the number one reason for failure which can also be attributed to the rapid ascent profile of Kilimanjaro.
  • AMS symptoms are divided into three levels: mild, moderate, and serious, Each one has been discussed below briefly.
Mild Symptoms

This include but not limited to: headache, fatigue, shortness of breath, disturbed sleep, loss of appetite, nausea and dizziness.

If you start to experience any of the above, it is important that you communicate the same with your troop and guide and let them know exactly how you’re feeling. Most of these symptoms will fade away if you rest at that altitude for a day. That’s why an acclimatization day is set aside if you climb too high or sleep low!

Moderate Symptoms

These include: More than normal headache, feeling nauseous which results in vomiting, very weak and fatigued, decreased coordination (also called ataxia), shortness of breath.

A sure shot sign of moderate altitude sickness is when one or all of the mild symptoms start to get worse to a debilitating degree. People who experience moderate symptoms tend to have very bad headaches followed by vomiting. Decreased coordination among body parts is common too.

People can often walk on their own when experiencing moderate AMS, however ascent under such symptoms will almost certainly result in worsening of the symptoms to a degree where one cannot walk anymore. This would necessitate a stretcher evacuation, which should be avoided at all costs.

Ascending under moderate symptoms has even resulted in death of a number of trekkers.

To counter the effect of moderate AMS, it is necessary that you descend down to 1,000 feet or more and remain there until things start to get better. Once properly acclimatized, you can ascend further with care.

Serious or Severe Symptoms

These include: Inability to walk, loss of mental capability, shortness of breath even at rest, hallucination, fluid build up on the lungs.

It’d be really difficult to walk under serious AMS symptoms and doing so is extremely dangerous. People who’ve experienced AMS at the extreme level are generally unable to walk, struggle to breathe, and have difficulty thinking and making decisions.

Two more severe forms of AMS which occurs when fluid leaks through capillary walls to lungs and brain are also experienced by trekkers. With it leaks to lungs, it is known as High Altitude Pulmonary Edema (HAPE), and if into the brain, it is called High Altitude Cerebral Edema (HACE).

both of the conditions rarely occur when one ascends to a higher level too quickly without being acclimatized and stay in that elevation for too long. The conditions are discussed below in brief:

Abbreviated as HACE, it is a medical condition closely associated with severe Acute Mountain Sickness. When the brain tissues swell and fluid up in the cranium, it causes several problems including severe headache. It is categorized under life threatening conditions.

If anyone suffers HACE in Kilimanjaro, the trekking journey is immediately abandoned and the person is made to descend immediately and rushed to the nearest medical center.

HACE can be identified and confirmed if someone is shows following symptoms:

Severe headache which are unrelieved even with required medications, loss of consciousness, loss of coordination, loss of memory, hallucination, disorientation

HACE tends to occur at night time. If any of your group members is suffering from HACE, do not hang around until morning. The more you remain at that altitude, more severe the condition becomes. Descend on immediate effect even under darkness. Ascending further should be strictly denied if HACE symptoms show up. IF you’ve got oxygen cylinders with you, it can be administered with dexamethasone steroid, but only in parallel with rapid descending activity.

High Altitude Pulmonary Edema is another physiological condition associated with AMS in which the fluid builds up in the lungs as opposed to brain in HACE.

The fluids that get accumulated in lungs prevent effective exchange of oxygen. Consequently, there’s a reduced supply of oxygen into the bloodstream.

Majority of the time, it occurs if one rushes to higher altitudes without taking breaks.

It is also a life threatening condition and precaution should be taken to avoid it at any cost while trekking Kilimanjaro.

A person is suffering from HAPE if the following symptoms occur:

Shortness of breath even at resting, tight chest, feeling of suffocation while sleeping, coughing with ejection of white, frothy fluid, extreme weakness with inability to walk, hallucination and irrational behavior.

If one experiences the last symptom (i.e. confusion, hallucination and irrational behaviour), then it’s a sign that pulmonary edema has started to affect the brain due to insufficient amount of oxygen in the bloodstream.

Any available oxygen should be properly administered with use of Nifedipine drug which ameliorate the condition to a degree. But descending down is the only cure.

It should be taken care of that person descending down with HAPE doesn’t exert himself that can worsen the condition. A stretcher evacuation is the preferred method.

After reaching at the lower elevation, the person should let rest and medical support should be sought immediately.

Trekking Kilimanjaro can be made a very safe affair if you abide by following basic rules.

In particular:

You should try to make every possible effort to pre-acclimatize yourself. A good option is to trek Mount Meru (4,565 m) before attempting Kilimanjaro.

If you’re an inexperienced trekker, we advise you to choose a route that’s at least seven days long (6 up, 1 down). Hence, seven or eight days trek through Machame and Lemosho route is suited for novice trekkers.

  • You’ve to ensure that the route offers good climb high, and sleep low opportunity, as in the case with both Machame and Lemosho.
  • When you’re on the mountain, take measures to progress slowly with not putting too much stress on body even on lower elevation.
  • Have sufficient water (2.5 to 4 liters on average per day).
  • Abstain from drinking alcohol, taking stimulant or drugs, smoking, or drinking caffeine the entire time.
  • We recommend taking acetazolamide (Diamox)
Finally, also take care of these three golden rules at high altitudes as laid out by Aktitude.org
  • If you’re feeling unwell, chances are you’re suffering from mild altitude sickness until proven otherwise.
  • Once the signs are confirmed, pause the ascend journey immediately.
  • If signs are getting worse, descend with immediate effect.

Drugs like acetazolamide or diamox are proven to be effective at mitigating altitude sickness.

The drug increases blood’s acidity level by acting as a diuretic which promotes urination. The increased acidity level in the body is treated as increased CO2 levels inside the body. This deepens our breathing and make us breath faster. Consequently, the amount of oxygen in the bloodstream increases which help ease symptoms of AMS.

Diamox is an important prophylactic (preventative medicine) which does not contribute towards curing AMS. That can only be done through descending down. Hence, Diamox shouldn’t be used to supplement your ascend.

Diamox is also a prescription drug, hence it is important to consult with your doctor first on whether or not it is suitable for you. Pregnant women, and anyone with kidney or liver disease are barred from this drug

We recommend testing with DIamox 2 weeks prior to your trek for 2 to 3 days to see whether or not you experience any side effects.

Typical Diamox side effects include:

Frequent Urination – After taking Diamox, everyone tends to urinate more often than they’d normally. Kidney stones can develop with intake of this medicine. Hence you should drink loads of water while you’re on this medication.

Numbness and tingling in face, toes, and fingers – After taking Diamox, numerous people reportedly experience this sensation which might be little discomforting, but certainly not dangerous.

Taste Alteration – Some foods might taste different or weird.

Nausea, vomiting, and diarrhea – Although this side effect is rare, there are still some slight chance of its occurrence. Before departing for Kilimanjaro, it’ll evidently show whether you’re develop such symptoms or not while you’re in Kilimanjaro. As these side effects are common with AMS as well, it is easy for them to be misdiagnosed as AMS.

Drowsiness and Confusion – These signs do show up after intake of Diamox, but are also confused with AMS.

Diamox comes in 250mg tablets. Half is taken in the morning while the other half in the evening. You should start the medication few days prior of arriving at Kilimanjaro and continue with the required dosage till you reach to the top. You might consider abandoning Diamox while you descend.

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