Climbing Aconcagua – Aconcagua Expeditions





Getting to Mendoza is easy.


The main access routes to get to the Province of Mendoza are the capitals of Chile –Santiago de Chile– or Argentina –Buenos Aires–. You can travel by either bus or plane from both cities.




When buying an international flight ticket, there are two airport entries to get to Mendoza city.

One option is to take a flight to the city of Buenos Aires, which is separated by 1,200km from Mendoza city. This flight takes no more than 1 hour with 50 minutes. If you choose a regular bus, the estimated time to arrive is about 14 hours.

The second option is to get to the International airport of Santiago de Chile. From there, you can take a flight that makes the 350 kilometers that separate Santiago de Chile from Mendoza in about 30 minutes. On a bus, it takes about 6 hours.

The two main airlines that make flights from both capital cities are Lan and Aerolineas Argentinas.


These are some of the pros and cons of the two options:

From Buenos Aires:


All international flights arrive to Ezeiza International Airport (EZE), but domestic flights fly from Aeroparque Airport (AEP), which is a different airport. So, once you get to Buenos Aires, you should change the airport to make the connection that will get you to Mendoza. The main problem regarding this, apart from changing the airport, is the inconvenience generated by the traffic. It takes 30 minutes to make the trip between airports if the traffic is normal. When buying your ticket, don’t forget to ask for flights that departure to Mendoza from Ezeiza Airport, saving yourself from this delay.
Always try to buy your ticket to Mendoza, to fly on the same day you arrive to Buenos Aires. It will help you avoid the transfer to the city of Buenos Aires, a hotel night and the transfer to Aeroparque airport.
In Buenos Aires, like in most big cities, you must be extremely cautious with your luggage. Keep an eye on it at all times!
If you buy your flight ticket from Buenos Aires, we recommend you to stay at least one day in this beautiful capital, since it is absolutely worth it. Don’t forget to ask us if you need and extension on your trip.


From Santiago de Chile:


The biggest advantage of entering from Santiago de Chile is that, unlike Buenos Aires, all the flights come and go from the same airport. This saves a lot of time in unnecessary transfers.
The flight to Mendoza takes only 30 minutes on a plane or 6 hours on a bus. Both options are, in comparison, cheaper and faster.



We strongly recommend you to arrive with at least one day of anticipation before the beginning of the expedition (day 1 of the program). Many situations can cause you involuntary problems, such as delays in the flights or losing your luggage.

Please feel free to ask us if you have a question or need additional information. We can help you!



Climbing Aconcagua is a challenging and demanding activity. Before starting the expedition, mountaineers must be both physically and psychologically well prepared. For this reason, each person interested in ascending Aconcagua should have a medical check-up before attempting to climb it.


We recommend you to ask your doctor for medical advice to be sure that your age, health status and physical condition are apt for making efforts at high altitude. If you have any prior medical condition or you are under any prescribed medication, you must ask your physician to see if any of them would affect your acclimatization process or your performance in the altitude.


According to the authorities of the Aconcagua Provincial Park, pregnant women and people under the age of 14 are BANNED from entering to the park.

If you are 65 or older, you will be requested a MANDATORY medical certificate to support your physical and psychological health, in order to participate in an expedition of this scale.

When buying any of our Trekkings or Expeditions, we will ask you to complete a Booking Form. This form has a section called“Questionnaire on Physical Condition” with a series of questions related to your health. This information is extremely relevant to us, since it is key in our taking proper care of you. It is also very important that you complete it with accuracy. Once you arrive to Mendoza, YOU MUST SIGN this document before starting the program.


Do not hesitate to consult us in case you have any health problem that makes you feel uncertain about your physical performance at height. ACONCAGUA MOUNTAIN GUIDES will send your request to the Medical Staff of the Aconcagua Provincial Park to provide with recommendations about it.


Note: Remember to bring your personal First Aid Kit with the medicines you regularly take. Some important items to include in it are: Aspirin, medication for stomachache, medication to treat Diarrhea, Band-Aids, Eye Drops, Sunscreen of SPF 50 or better and Lipscreen of SPF 30.



To enter Argentina you must have a valid passport with enough time prior to its expiration. A visa will be required, depending on the country where you are coming from.


Argentina doesn´t require a vaccination certificate. This will be requested only to passengers coming from countries in which yellow fever or cholera are present or endemic.


All the citizens from the following countries: USA, Canada, The European Union, Australia, New Zealand, Bolivia, Brazil, Chile, Paraguay, Uruguay, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, México, Nicaragua, Panamá, Peru and Venezuela DO NOT NEED A VISA to enter Argentina.


As soon as you get to the first check point at the airport you will be given a tourist visa valid for 90 days. DO NOT LOSE THIS DOCUMENT, or else you will be required to fill another one and repeat the procedure when leaving.



To enter Argentina, citizens from United States of America, Canada and Australia must pay a reciprocity fee. This fee IS NOT A VISA. The amount to pay for this fee is equivalent to the amount that Argentinean citizens pay when requesting a visa to the listed above countries:


United States of America: U$D 160.- for multiple entries in a 10 year period.
Canada: U$D 100.- for one entry, or U$D 150.- for multiple entries in a 10 year period (from the first entry).
Australia: U$D 100.- for multiple entries in a 1 year period.


Note: The above mentioned prices can be modified depending on the reciprocity.

Payment options: Argentinean pesos, US dollars, credit/debit card, traveler checks.


Exceptions to the reciprocity fee:

      Argentine citizens with American, Canadian or Australian nationality with a valid passport to use in any immigration checkpoint.

Foreign citizens with American, Canadian or Australian passport that are in transit.

Foreign citizens with American, Canadian or Australian passport with permanent residence in Argentina.

Foreign citizens with Canadian passport and a business visa.

Foreign citizens with official or diplomatic passports from United States of America, Canada or Australia.


All foreign citizens that have previously paid the reciprocity fee will not be requested to pay it again if its validity hasn’t expired.


Please feel free to contact us if you have a question. We can help you!




This is a brief summary with all the basic information on the acclimatization process.

It is very important that you are well informed on this subject, because if your plan is to come to climb Aconcagua, this will definitely be one of the main obstacles to overcame. The better informed you are, the greater adjustment on your focusing you can make to overcome the uncertainty, recognizing and understanding what is happening to your body.


If you may have any doubt or question, do not hesitate on contact us. We will gladly answer your questions.

Lack of oxygen?

Opposite to what most people believe, there is no less oxygen in the altitude than in the sea level.

If we have the same amount of oxygen in a beach than in the Summit of Aconcagua, why is it so hard to breathe up there? The answer is very simple. What really differs is the atmospheric pressure, which shifts significantly in the altitude.

At the sea level, the weight of earth’s atmosphere makes a pressure that equals the weight of a mercury column of 760map (millibars of atmospheric pressure) high. We know this by the name of atmospheric pressure. Oxygen is the 20% of the composition of earth’s atmosphere.

As we go up in height, that 20% of oxygen remains constant, but the reduction in the atmospheric pressure makes the oxygen particles decrease with every breath we take.

For example, at 4,800m over the sea level, the pressure is just 405map, so we receive a 40% less of oxygen in every inspiration, whether we are moving or resting.

When we reach an altitude of 6,962m (Aconcagua’s summit), the atmospheric pressure is only 290map. So, we get only a 37% of the oxygen we have when we are at sea level.

Hence, what matters is not the concentration of oxygen we breathe, but the pressure we have in our lungs –the place where the gas exchange happens– when receiving it.

This means that, without a chance to help it, this thinning in the air we inhale will produce a cellular hypoxia in our body, showing clear symptoms that we will describe later.

Without exception, we all go through these symptoms when we make a trekking or take part in an expedition to a high altitude mountain.

According to the Association pour la Recherche en Physiologie de L’Environnement (Association for Research into Environment Physiology), one in two people will be affected by AMS (Acute Mountain Sickness), and one in a hundred will be severely affected by the complications of pulmonary or brain edema.

Physiological effects of altitude in humans

What happens to our body when exposed to the altitude? Let’s remember that although the percentage of oxygen in the air remains the same, the atmospheric pressure changes. The higher we get, the less atmospheric pressure we have. The exposure to the altitude is the origin of different changes and adaptations in the circulatory, respiratory, muscular, metabolic, hematologic, neurologic and psychologic systems. 


Heart: When we start the exposure to the altitude, the stroke volume increases similarly as when we make exercise, to later decrease. This decreasing in the maximum rate is an adaptation to limit the use of oxygen in the body.


Lungs: The initial response of any person to a low oxygen pressure in the altitude, is an increase in the breathing rate –technically called hyperventilation–, which consists in the increase of the respiratory and breathing frequencies.As extreme heights are reached, normal face additional impediments lungs to transfer oxygen to the blood.


Muscles: Several studies back the statement that staying in high altitude produces deterioration in the skeletal muscle. The loss of aerobic response in extreme altitudes is made by both the reduction of oxygen in the muscle and the deterioration of the muscle cells (myocytes). A study conducted on 15 climbers before and after ascending mountains over 8,000 meters, revealed a lessening in their body weight for around 4 kilograms. This anthropometric study also demonstrated that most of the body’s fat is lost during the approach and the first days in the altitude, while most of the skeletal muscle loss happens over 5,200m high.


Sleep: In spite of the normal fatigue produced by the activity, those who move in the altitude often have a non-repairing sleep, because of the diminishing in the stages 3 and 4 of the dream, and also in the REM stage. In addition to a poor quality sleep, many individuals present irregular breathing (sleep apnea) in intermediate altitudes, while everybody presents the same condition in altitudes over 6,300m.Altitude sleep is characterized by long periods of sleeplessness. This, alongside the other factors, make an unsatisfactory sleep, with a subsequent fatigue during the day. After acclimatizing, all the AMS symptoms related to sleep can be surpassed.


Fluids / Dehydration: Diuresis happens with the loss of water and sodium when the body is struggling to acclimatize to the altitude. The consequence of this, is the risk of dehydration, especially when making a strenuous physical activity.

Urinary output or diuresis is one of the key components for a successful acclimatization to the altitude. Acute Mountain Sickness –an unsuccessful adaptation to the altitude– is characterized by a lessened diuresis, in which the fluids that form the plasma move towards the cells and interstitium (the solution that bathes and surrounds the tissue cell), resulting in face and “pitting” (cutaneous) edema in the form of swelling. Mount Aconcagua has a very cold and dry atmosphere, which will lead to losing a great amount of water. To prevent dehydration and all the aforementioned symptoms, it is very important to increase the drinking of all kind of beverages.


Appetite / Nutrition: Nausea and anorexia are common signs.Due to the relevance in the extra intake of liquid –to replace the ones we lose–, the lack of will to drink, added to vomiting, can worsen the diagnosis. A diet that is high in carbs can be helpful, while a low sodium diet can reduce the peripheral pitting edema. If someone can’t increase the number of red blood cells (in charge of carrying oxygen in the body) during the acclimatization because of iron deficiency, they should supplement it in their diets. This applies particularly to women during their period.


Neurological / Psychiatric: The first, and sometimes the most common, symptom of AMS is the headache, which can go from moderate to incapacitating. It tend to be unilateral and throbbing. It feels worst in the morning and intensifies with active physical activity. Individuals with a history of migraine have a greater chance to develop headache produced by AMS. Headaches can also be caused by the benign vasodilation as a response to hypoxia.Once the body acclimatizes to the intermediate altitude, headaches disappear.

The higher the altitude reached, the grater the alterations in the sensory perception, the visual memory and the verbal coordination. Visual acuity decreases in low visibility environments, and the person can suffer from visual or hearing hallucinations, as well as indifference or lack of danger assessment. Other symptoms are the desire of giving up –regardless of the place or conditions–, anguish, hostility and problems of coexistence with other team members.

What is Acute Mountain Sickness (AMS) and what are its symptoms?

Around the year 37 BC, ancient Chinese people recognized a peculiar illness when they walked through what they later called “Great Headache Mountain and Little Headache Mountain”. Since then, researchers have described the consequences of traveling to the high altitude, calling this phenomena Acute Mountain Sickness (AMS). 


Every person exposed to the altitude will suffer from symptoms that range from slight acute mountain sickness to the potentially fatal High Altitude Pulmonary Edema (HAPE) or High Altitude Cerebral Edema (HACE). 


The beginning of all the symptoms happens within the following hours after arriving to the altitude. Those symptoms depend on a variety of factors such as personal sensitivity, the way in which the person arrived to the altitude (walking, horse riding, car, helicopter, etc.), lapse of time on gaining the altitude (daily slope progression), walking pace, weight carried in the backpack, feeding, hydration, clothing, psychological condition and previous experience.


The early acknowledgement of the symptoms is decisive, since an early detection of the problem, alongside the proper information background and preparation, can turn a critical situation into an anecdote. Ignorance on this delicate matter can lead to a serious condition.  

AMS Symptoms are:

Loss of appetite
Sleep disturbances and insomnia
Peripheral edema (eyes, face, hands, etc.)
Irregular breathing (especially at night)
Ataxia (lack of coordination and balance)
Weariness (excessive fatigue and tiredness, usually accompanied by loss of interest in eating or drinking)


Acute Mountain Sickness is characterized by a number of symptoms. Headache is probably the main one. Others include nausea, vomiting, dyspnea (difficult breathing) and insomnia among the most usual.


High Altitude Pulmonary Edema (HAPE): For reasons that from a medical point of view are not too clear yet, the diminishing in the atmospheric pressure causes an escape of fluids in the capillary vessels that may overload the lungs with fluid, preventing the gas exchange necessary to live. The person may experience breathlessness and loud breathing, cyanosis (blue or purple coloration of lips or ears) and coughing up of pink and frothy sputum. The manifestation of these signs can appear during the night, after a day of oversized effort.


High Altitude Cerebral Edema (HACE): It happens for similar reasons as HAPE, only that in this case, the brain is swelled by escape and accumulation of fluids. The most common symptoms are hard vomiting, extreme weakness –not in every case–, severe headache that cannot be stopped with an analgesic, lack of coordination, dizziness, distressed behavior, small hemorrhages and bleedings in the eyeballs and eventually coma. It can occur after a long staying (over a week) in altitudes over 6,500 meters.


In both cases the main danger is death. So, it is vital to rapidly descend (no less than 600m or 1,000m of slope) and to provide oxygen to the person affected. If you feel any of the above mentioned symptoms, you must communicate to your teammates or the guide to act as rapidly as possible.

AMS diagnosis. Lake Louis score.

The finding of AMS is based on clinical symptoms rather than a specific diagnosis on the subject, since there isn´t any sign that, by itself, unmistakably identify a case of AMS.


The most widely used method to appraise the symptoms is known as the Lake Louise Score



Mild headache – 1 point
Did not sleep as well as usual – 1 point
Poor appetite or nausea – 1 point
Mild dizziness – 1 point
Moderate headache (doesn’t go away with analgesic) – 2 points
Moderate nausea & /or vomiting – 2 points
Dyspnea at rest (short of breath) – 3 points
Severe fatigue / weakness – 3 points
Oliguria (urine output) – 3 points


The sum of all the points leads to a total score, with which we can classify the AMS into Mild, Moderate or Severe:


– MILD AMS  –  from 1 to 3 points

– MODERATE AMS   –  from 4 to 6 points

– SEVERE AMS  –  7 points or more

Acclimatization as a way to prevent AMS:

Acclimatization is the process by which our boy adapts to the altitude. When a person is acclimatized –after staying many days in the altitude– it is unlikely that he will present symptoms of AMS. However, it is very important to understand that such acclimatization works for a specific altitude, and that AMS can appear when we continue ascending.


The process of acclimatization must be made step by step, taking the necessary time on each stage of the climb to allow our body to make the proper adjustments.


Sometimes, people who integrate an organized expedition can have difficulties following the pace of the scheduled program, underestimating the relevance of AMS symptoms under the belief that those symptoms can delay the entire group or let them out from the team and a long-cherished dream. You must keep informed your guide at all times if any sign appears, because he has the knowledge and experience to make the best decision for you to acclimatize better.

Practical tips to acclimatize

Acute Mountain Sickness always gives a hint. It never happens in an unexpected or violent way. The important thing is to identify the symptoms when they appear and never underestimate them. Everyone is exposed to AMS.


Medicine should never be used as alternative treatment in moderate or severe AMS cases. The prescription and dosage of all the described drugs must be supervised and controlled by a physician or a certified –and qualified– mountain guide, since they are the only ones that know the interactions, contraindication and side effects on all them.


Ascend by walking slowly (not by mule, helicopter, etc.).


Avoid loading yourself excessively or make sudden and violent moves. For example, the setting up of tent, which in a low altitude can take 10 to 15 minutes, in higher altitude can double that time.


Use a diet based on carbohydrates, but not forgetting the protein. In altitudes over 5,500 meters, the fuel used to perform the activities are the aforementioned proteins, due to a process called neoglucogenesis. If we fail to provide them as food, the waste of energy is going to be produced by the burning of skeletal muscle. It is also advisable not to overcharge our stomach. Research has showed that production of gastric acid decreases in the altitude. Keep in mind that fats are hard to digest and oxygen consuming in the altitude, far more than carbohydrates.


Hydration must be abundant. To think that we can make do with 3, 5 or 6 liters is incorrect, because it depends on many factors such as room temperature, walking pace, daily activity, body weight and many other aspects. The best way to see if we are hydrated is to monitor our urine when peeing.  If the color is yellow, we are dehydrated. The best sign that we are drinking what we need to fulfill the acclimatization requirements, is a transparent urine.


Never drink water made from thawing snow without adding salts or sugar through tea, soup, juice, etc.


A good previous training: Although being properly trained doesn´t guarantee protection against altitude sickness, it is illogical –borderline irresponsible– to face the climb of a high mountain without proper physical, and therefore physiological, preparation.


Choose your clothes accordingly: This means to select our clothing gear depending on the weather conditions, as well as the temperature. This will prevent over heating or excessive perspiration, which eventually can lead to losing important minerals and fluids. Each person must find the right balance depending on how much they sweat.


Avoid the use of alcohol, tobacco, sedatives or sleeping pills (Valium®, Lexotanil®, Trapax®, Alplax®, etc.).


Avoid sleeping or napping during the day, because it can reduce our oxygen level in the blood. It is preferable to make a moderate physical activity.


Know the symptoms of AMS and learn to give them the proper relevance if they may appear.


Never go to sleep in a new or higher altitude if you have any symptom of AMS, regardless of how small it may seem.


Descend if the AMS symptoms persist or worsen in the altitude where you are.


It is well known in the mountain world that some drugs can help in the process of acclimatization, lessen some of the unpleasant effects caused by the altitude. The most used ones are Acetazolamide (Diamox), Dexamethasone and Ginkgo Biloba.


The fact that these drugs reduce the risk of having Acute Mountain Sickness does not mean that a person should take them. Every medicine has its pros and cons.


For those with difficulties to acclimatize, the best option is to use more days and carry the program more slowly to get better chances.


Do not self-medicate. Do not use diuretics or any other drug without medical authorization. Medicines usually cover the symptoms of edema, making harder to identify them until it is too late. When in doubt consult and get written consent from physician.


Dexamethasone (oral or injection) and Nifedipine are drugs used in case of pulmonary or cerebral edema, and should be used after being diagnosed by a physician.


For headache (the most common symptom in the altitude) it is recommended to use Aspirin (acetylsalicylic acid), not only for its analgesic properties, but also because it is an effective blood thinner. This is important since the loss of plasma in the blood thickens it. It is not recommended for people who have or had ulcer. If you cannot take Aspirin, it is suggested to replace it with Paracetamol.