Altitude sickness: how to combat and avoid it

Altitude sickness: how to combat and avoid it

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The altitude sickness or soroche (Acute Mountain Sickness) is the lack of oxygen in the organism generating an altitude hypoxia. This is directly related to the speed of ascent and the altitude reached, normally occurring from 2500 m.a.s.l. to an altitude of 7500 m.a.s.l. known as the death zone.
This altitude sickness is usually in people under 50 years of age and in people who live at an altitude lower than 1000 m.a.s.l. The main cause of hypoxia is lack of oxygen in the body because the atmospheric pressure decreases with altitude, which affects the bioavailability of oxygen, where the pulmonary alveoli are not able to transport the same amount to the blood.

What are the main causes of altitude sickness?

There are many causes of altitude sickness, however, these are the main ones.

  • - The amount of oxygen to sustain mental and psychological attention decreases as altitude increases.
  • - The dehydration that is generated due to the altitude.
  • - The previous bad acclimatization of the organism to the altitude.
  • - Speed of ascent.
  • - Previous state of health.

Also the appearance of altitude sickness can worsen existing diseases such as hypertension, heart failure, chronic lung disease, anemia, among others.

Main symptoms of altitude sickness

Symptoms usually appear hours after reaching an altitude where the following symptoms may occur.

  • Fatigue with shortness of breath or shortness of breath.
  • Headache.
  • restlessness
  • Chest pain
  • Physical exhaustion to perform activities.
  • Nausea and vomiting
  • Sleep disorders presenting difficulty sleeping or drowsiness.

The most serious symptoms are pulmonary edema and cerebral edema.

Pulmonary edema is a non-cardiogenic pulmonary edema that may occur in subjects exposed to hypoxemia (decreased oxygen in the blood) due to altitude. Symptoms may include shortness of breath (dyspnea), cough (which may be accompanied by frothy, pinkish secretions), crackling or "bubbling" respiration and chest pain. Fever and altered levels of consciousness may also sometimes occur. The onset is usually sudden and its evolution is lethal unless descending to lower altitudes immediately, at least between 300 and 500 m. although ideally as much as possible, including transfer to hospital of the affected subject. EPA is considered a form or malignant evolution of Acute Mountain Sickness, Altitude Sickness or Mountain Sickness.

Cerebral edema: it is a very serious alteration or dysfunction of the central nervous system, with risk to life, which may occur in subjects exposed to altitude hypoxia. The cause of this clinical manifestation is the presence of edema in the brain tissue. Symptoms may include headaches, loss of coordination (ataxia), weakness and loss of consciousness levels, including disorientation, memory loss, hallucinations, psychotic behavior and coma. Its evolution is lethal unless descending to lower altitudes immediately, at least between 300 and 500 meters, although ideally as much as possible, including transfer to hospital of the affected subject. ECA is considered a form or malignant evolution of acute mountain sickness, altitude sickness or mountain sickness.

Prevention of altitude sickness

To avoid developing the disease we should take some precautions in case we have to ascend to important altitudes:

  • Gradual ascent with adequate time for acclimatization is the best prevention: ascend about 500 m per day at most.
  • Sleep at an intermediate altitude (1,500-2,000 m), before ascending above 2,500 m.
  • When flying to high altitude cities, rest and moderate physical activity until the body has acclimatized.
  • Avoid alcohol, especially during the first few days.
  • Consciously increase the depth of breathing.
  • Decrease salt in meals.
  • Avoid taking sedatives, as they slow down our breathing rate.
  • Watch your urine: it should be clear, and not "caramel colored".
  • If you are going on an expedition to a high altitude, you must be equipped with oxygen, suit-bag, and appropriate medication for the treatment of altitude sickness.
  • If you are taking the contraceptive pill, it is preferable to change the method of contraception, because of the tendency of this drug to thrombosis and fluid retention.
  • If you are taking antimalarial prophylaxis, you should stop taking it (malaria is not transmitted above 1,800 m), as it can mask the first symptoms of altitude sickness.

Treatment of altitude sickness

Mild cases resolve within one to three days. Severe cases may require oxygen, medication and transfer to a lower altitude.

Descent to a lower altitude

If symptoms of acute mountain sickness are more severe or if they persist or worsen despite treatment, the person should descend to a lower altitude, preferably to an altitude 500 to 1000 m below the initial altitude. Descent often provides rapid relief.

Oxygen therapy

Oxygen therapy is a therapeutic measure consisting of the administration of oxygen at concentrations higher than those found in ambient air, with the intention of treating or preventing the symptoms and manifestations of hypoxia.


- Acetazolamide (sold as Diamox) to prevent and treat altitude sickness.
- Soroche pills (a very popular pill among Peruvians).
- Ibuprofen and paracetamol to treat headaches.
- Gravol or promethazine to treat nausea.

Frequently asked questions about altitude sickness

Do I need a pre-health check-up to travel to high altitude?

If you are going to travel to high altitude, we recommend you to have a medical examination in order to detect pathologies for which you may be exposed to high altitude.
The health examination should contain identification data, usual job, allergies, personal history (inquiring about heart and lung diseases suffered, anemia, polycythemia, sleep apnea, diabetes, vertigo, epilepsy and other neurological or psychiatric processes and previous stays at high altitude), also family history, toxic habits and lifestyle and usual medication. Symptoms or alterations that could be related to altitude (especially cardiological and pulmonary alterations) will be investigated. The examination to be performed should be logically coherent with the apparatus and organs involved in the risk of high altitude (ears, balance, heart, lungs, circulation, kidneys, etc.).

To avoid altitude sickness should I acclimatize?

In acclimatization the body adapts (acclimatization) to higher altitudes by increasing respiration and producing more red blood cells (erythrocytes) to transport oxygen to the tissues, as well as making other adaptations. Most people can adapt to altitudes up to 3000 m in a few days. Adapting to higher altitudes requires many days or even weeks, but some people can, over time, carry out almost all normal activities at altitudes above 5300 m (17,000 ft). However, no one can fully acclimatize to living permanently above that altitude.

How long can altitude sickness last?

Some people describe the symptoms as similar to those of a hangover; symptoms usually last from 24 to 48 hours. Rarely, acute mountain sickness can progress to a more severe type of altitude sickness, called altitude cerebral edema.

What medicine is good for altitude sickness?

People with severe acute mountain sickness may need to stay in the hospital. A medicine called acetazolamide (Diamox) may be given to help you breathe better. It may also help decrease symptoms.

Is it good to take mate coca for altitude sickness?

The second most commonly used form of coca leaf consumption to combat soroche is through a mate, which is an infusion of the coca leaves. You can add the leaves directly to your cup with hot water or use filtered water. The taste may be a little bitter at first, but, once you get used to it and notice its effects on your body, you will know that it will be worth it.

What to eat for altitude sickness?

Because altitude dehydrates, it is advisable to drink between 4 to 5 liters of water per day, in addition to consuming foods that give energy to your body such as: Andean grains (quinoa, kiwicha), fruits, jams, cereals, among others.

Why does the head ache at high altitude?

Altitude sickness, or mountain sickness, is caused by a lack of oxygen at high altitudes. Symptoms include headache, fatigue, nausea or loss of appetite, irritability and, in more severe cases, difficulty breathing, confusion and even coma.

Why does altitude affect breathing?

The effects of altitude are due to low barometric pressure and, therefore, a reduction in the partial pressure of oxygen in the inspired air. This condition of hypobaric hypoxia is the cause of alveolar hypoxia and hypoxemia in humans living at or ascending to high altitude.

How to breathe at high altitude?

It must be deep and abdominal. Breathing with the diaphragm is the most effective way. In addition to calming you down, it provides more oxygen to your body. By developing a conscious and regular breathing rhythm before starting the climb, it is easier to maintain it during the climb.


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