CLIMB PREPARATION

ACCLIMATIZATION

The Altitude

Altitude is the most critical and dangerous obstacle in ascending the Aconcagua. Anyone planning to summit Aconcagua has to know necessary information about the altitude.

The Air and the Atmospheric Pressure

Air is primarily made up of 21% oxygen and 79% nitrogen. This percentage keeps invariable at any height. In normal circumstances, oxygen pressure at sea level is 760 mm x 21% = 160 mm of mercury. As one ascends through the atmosphere, barometric pressure decreases (though the air still contains 21% oxygen), so oxygen pressure goes down in the same proportion as the atmospheric pressure.

Atmospheric pressure and oxygen proportion

Pressure is the only force, which pushes oxygen from the air to the cells in our body. Low pressure at high altitude causes many problems for climbers.
One must work harder to obtain oxygen, by breathing faster and more profound.

Acclimatization

It’s the process of the body adjusting to the decreased availability of oxygen at high altitudes. It is a slow process, taking place over a period of days to weeks, depending on your own physiology and circumstances.
Practically speaking; however, we generally don't worry much about elevations below about 2,500m (8,000ft) since altitude illness rarely occurs lower than this.
No single factor such as age, sex or fitness will affect your likelihood of being affected.

Specific regular physiologic changes occur in every person who goes to altitude:

Remember this it’s not about your physical shape, it’s about physiology, but a good fitness helps as a good use of your daily energy level according to age and conditions are critical.
It’s about how your body adapts not only to altitude but as well to a set of different conditions such as dry mountain air, daily outdoor exercise routine, variable temperature regime, windy conditions and so on.
The physiology of how humans do adapt to altitude is quite known but the reasons why similar people do react so differently, or the same person react not always the same at different times, places, circumstances still cause of debate and uncertainty.

So, how do you find out if you could do it or not?
The only reasonable, sound answer its begin in lower mountains / shorter expeditions, as a process to know how your body is reacting to altitude. So, if you do a lower peak, shorter adventure and you feel ok, you may continue with more important objectives.
Aconcagua is a massive mountain; we suggest you get some previous experience on altitude climbs as Ecuador volcanoes, Kilimanjaro or others.

Altitude Sickness

Also known as Acute Mountain Sickness (AMS), is a pathological effect of high altitude on humans, caused by acute exposure to low partial pressure of oxygen at high altitude.
It presents as a collection of nonspecific symptoms, acquired at high altitude or in low air pressure. Many people will experience mild AMS during the acclimatization process.
Symptoms tend to be worse at night when your breathing rate decreases. As long as symptoms are mild and only a nuisance your ascent can continue at a moderate rate. It is essential that you communicate any signs of illness to the guide of your trip.

AMS can be divided into three categories, MILD, MODERATE & SEVERE.
The following table shows a score that can be assigned to each of the symptoms to detect AMS and determinate its category.

Severe AMS: Is characterized by the presence of high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE), which are potentially fatal. These should not occur if a sensible acclimatization schedule has been adhered to and usually happens due to people going too high too fast. In both cases, the lack of oxygen results in leakage of fluid through the capillary walls into either the lungs or the brain.

The most essential and unbreakable rule is: IF YOU HAVE SYMPTOMS OF AMS, DO NOT ASCEND ANY HIGHER. Violating this simple rule has resulted in many tragic deaths.

If you ascend with AMS, you will get worse, and you might die. This is extremely important - even a day hike to a higher elevation is a high risk. In many cases of high altitude Cerebral Edema, this rule was violated. Stay at the same altitude (or descend) until your symptoms completely go away. Once your symptoms are completely gone, you have acclimatized, and then it is ok to continue ascending. It is always ok to descend; you will get better faster.

Altitude Sickness Prevention

First always follow the acclimatization Rules:

Things to Avoid

Respiratory depression (the slowing down of breathing) can be caused by various medications, and maybe a problem at altitude. The following drugs can do this, and should never be used by someone who has symptoms of altitude illness (these may be safe in persons who are not ill, although this remains controversial):

AMS Treatment and Medication

The mainstay of treatment of AMS is rest, fluids, and mild analgesics: acetaminophen (paracetamol), aspirin, or ibuprofen. These medications will not cover up worsening symptoms. The natural progression for AMS is to get better, and often merely resting at the altitude at which you became ill is adequate treatment. Improvement usually occurs in one or two days but may take as long as three or four days.

Descent is also an option, and recovery will be quite rapid.

A frequent question is how to tell if a headache is due to altitude. Altitude headaches are usually nasty, persistent, and frequently there are other symptoms of AMS; they tend to be frontal (but maybe anywhere) and may worsen with bending over. However, there are other causes of headaches, and you can try a simple diagnostic/therapeutic test. Dehydration is a common cause of a headache at altitude. Drink one liter of fluid and take some acetaminophen or one of the other analgesics listed above. If a headache resolves quickly and entirely (and you have no other symptoms of AMS), it is improbable to have been due to AMS.

Acetazolamide (Diamox®)

We do not recommend acetazolamide as a prophylactic medication. Most people who have a reasonable ascent schedule will not need it. Since acetazolamide works by forcing a bicarbonate diuresis, you will urinate more on this medication and in addition to you may experience some common minor but unpleasant side effects include numbness, tingling, or vibrating sensations in hands, feet, and lips. Also, taste alterations, and ringing in the ears. These go away when the medicine is stopped. A few trekkers have had extreme visual blurring after taking only one or two doses of acetazolamide; fortunately, they recovered their normal vision in several days once the medicine was discontinued. Acetazolamide is a sulfonamide medication, and persons allergic to sulfa medicines should not take it. Also, acetazolamide will NOT prevent AMS from worsening during ascent, acetazolamide just accelerated the normal process of the body adjusting to the decreased availability of oxygen, but if your body is not reacting, then it’s nothing Acetazolamide could do about it. So, if for whatever the reason you hit a wall due to the lack of O2, the only proved good strategy goes down and sometimes you need that little extra that a dose of acetazolamide gives you, to be able to walk down that 100-200m that will make all the difference.

Dexamethasone (Decadron®)

A potent steroid used to treat brain edema. Whereas acetazolamide treats the problem (by accelerating acclimatization), dexamethasone treats the symptoms (the distress caused by hypoxia). Dexamethasone can completely remove the symptoms of AMS in a few hours, but it does not help you acclimatize. If you use dexamethasone to treat AMS, you should not go higher until the next day, to be sure the medication has worn off and is not hiding a lack of acclimatization. Side effects include euphoria in some people, trouble sleeping, and an increased blood sugar level in diabetics.

Oxygen

AMS symptoms resolve very rapidly (minutes) on moderate-flow oxygen (2-4 liters per minute, by nasal cannula). There may be rebound symptoms if the duration of therapy is inadequate - several hours of treatment may be needed. In most high altitude environments, oxygen is a precious commodity, and as such is usually reserved for more severe cases of HACE and HAPE.

Important rules about altitude

Plan your expedition itinerary very carefully; aiming to give all the expedition members, the maximum chances to acclimatize naturally and safely.

Part of the strategy is based on basic rules, such as:

Nevertheless, acclimatization to the altitude is a personal feature that partially depends on physiology and much depends on you. Here some tips that will make the difference when climbing a 6,000 meters peak in the Andes:

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