Preparation to Climb Aconcagua


Altitude and Hypoxia

In statistical terms, altitude is the most important and dangerous of the complications involved to ascend the Aconcagua. For this reason, people who wish to carry out this adventure must know some details about how the altitude affects the human body and its entailment with AMS (Acute Mountain Sickness).

The air is essentially comprised of two gases: oxygen and nitrogen. No matter the height, the proportion of both gases is invariable: 21% oxygen and 79% nitrogen. The relation of this concept with Atmospheric Pressure (the pressure played by the weightof atmosphere above terrestrial surface) leads us to the concept of Oxygen Pressure. As we ascend above sea level atmospheric pressure decreases, resulting in the separation of the oxygen molecules (lower Oxygen Pressure), that is why the amount of oxygen which enters the bodyin one inhalation is inferior.

So, the reduction of atmospheric pressure as we ascend is an obstacle for our body´scellular oxygenation, generating Hypoxia. This brings into play a series of modifications to reach the adaptation to the new conditions proposed by the environment. This set of changes or adaptations of different organs or systems of our body is called Acclimatization.


Acclimatization is a gradual process, genetically codified, and as such, it is different from one person to another. It implies modifications on the respiratory and cardiovascular systems, the kidneys, the cerebral circulation, the affinity of hemoglobin 1 by the oxygen and red blood cells count, water metabolism and certain electrolytes, etc. This changes let the person carry trough the activities with certain efficiency and confidence, in spite of the prevailing hypoxia conditions

Aspects to consider in Acclimatization and prevention of AMS (Acute Mountain Sickness)

Gradual ascent: a slow progression and a good climb planning are unquestionably the best means to achieve a correct acclimatization and minimize hypoxia effect and its undesired derivations in (AMS) (mainly pulmonary edemas and the risky cerebral edema)

-Start your trek below the 3000masl.

-From the 3000masl, take an acclimatization night every 1000ms you climb.

-Once you are well acclimatized (after one or two weeks in height) it is easy to ascend 1000 or 1500ms a day.

Abundant hydration: it is recommended to drink in abundance, enough to obtain a clear and copious urine. If the volume or urine is small in spite of drinking the correct amount of liquid, we are facing a signal of bad acclimatization. It is very important to drink at least 5 liters per day to prevent AMS.

Diet rich in carbohydrates: we recommend a diet rich in carbohydrates. There are many studies in humans and animals which show that higher levels of oxygen in blood are reached during the first days in altitude with a diet containing carbohydrates in a 70 or 80%.

Medication: it is essential to be careful in this aspect, since the medication could be counterproductive. The azetosolamide (Diamox) reduces the incidence and severity of AMS. Until recently, it was believed that for an effective prevention, the medication had to be taken one or two days before ascending, however the ultimate studies have shown it works really fast, being able to ingest it the same day of the ascension. For further information, consult your doctor.

Our Expeditions considers the acclimation process to be a fundamental factor in the success of your adventure. This is why all expeditions that we offer are designed to achieve the highest possible degree of acclimation before attacking the summit. Therefore, we include one night in Puente del Inca, two in Confluencia and five in base camp at Plaza de Mulas. In this way, people who do not have much mountain climbing experience will be successful in reaching the summit.