Altitude Sickness

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Altitude Sickness
Altitude Sickness

Video: Altitude Sickness

Video: Altitude Sickness
Video: ALTITUDE SICKNESS 2023, September

Altitude sickness

Altitude sickness is a health problem caused by a lack of oxygen at altitude. Acute altitude sickness can develop if you travel or climb too quickly to great heights and the altitude-related lack of oxygen is not adequately compensated for.

Acute altitude sickness includes acute mountain sickness, high altitude lung edema and high altitude brain edema. A typical sign of acute mountain sickness is headache combined with other symptoms such as nausea or vomiting and dizziness. The cause is poor adaptation of the body (acclimatization) to the altitude reached. The symptoms usually pass when the body has acclimatized to the altitude after a while or when a lower altitude has been reached again. Sufficient acclimatization can prevent altitude sickness. Certain symptoms of acute mountain sickness, such as altitude headache, can be treated with medication.


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  • Advice, downloads & tools
  • ">How common is altitude sickness?


  • What types of altitude sickness are there?
  • Altitude acclimatization: what is it?
  • Preventing altitude sickness: Proper acclimatization
  • Acute mountain sickness: symptoms & therapy
  • High altitude brain edema and high altitude pulmonary edema: symptoms & therapy
  • Whom can I ask?
  • How are the costs going to be covered?


Failure to respond properly to the symptoms of acute mountain sickness can lead to life-threatening high altitude cerebral edema or high altitude lung edema. With these severe complications, rapid descent or removal to lower altitudes and medical care are vital.

How common is altitude sickness?

Acute altitude sickness can occur from a range of approx. 2000 meters. The most common is acute mountain sickness. Approximately every fourth person who lives at low altitudes and stays above 2,500 meters without acclimatization will develop symptoms of altitude sickness. In the Alps, very severe courses of altitude sickness are rare, as a quick descent to low altitudes is easy.

Some experts suspect that acute mountain sickness with typical complaints such as headache and fatigue also impair the ability to concentrate. This could add to an increased risk of accidents. At extreme altitudes above around 5,300 meters, severe life-threatening forms of altitude sickness such as high altitude cerebral edema and high altitude pulmonary edema occur more often and are among the most common causes of death in mountaineering.

What types of altitude sickness are there?

Depending on the symptoms and organs affected, a distinction is made between three types of altitude sickness (HAI). These clinical pictures can occur both alone and in combination with one another. The transitions are often fluid.

  • Acute mountain sickness (AMS)
  • High altitude cerebral edema (HACE)
  • High altitude pulmonary edema (HAPE)

Altitude acclimatization: what is it?

With increasing altitude, the amount of oxygen in the air decreases. This initially also reduces the amount of oxygen in the blood (oxygen partial pressure).

  • The body reacts immediately to the lack of oxygen (hypoxia) by accelerating breathing and increasing the heart rate (pulse).
  • In order to be able to transport more oxygen, more and more red blood cells (erythrocytes) are formed. This increases the number of cells in the blood (hematocrit). However, this effect is only found after weeks and is more pronounced at high altitudes than at medium altitudes.

Over about 1,500 meters, the altitude begins to make itself felt for many people. However, the level at which the body begins to acclimate varies from person to person. After staying at a certain altitude for some time, the body is adapted to this altitude.

Acclimatization is necessary again when climbing to a greater height. However, the body can only fully acclimate itself up to about 5,300 meters. Long-term stays are not possible at higher altitudes. Humans can only survive there for a limited time.

Preventing altitude sickness: Proper acclimatization

Acute altitude sickness can be avoided through adequate acclimatization. With successful acclimatization, the pulse is normal and breathing is deep.

The susceptibility and the "critical height" for the development of altitude sickness are individually different. What is essential for acclimatization is how much gain in height was achieved in which time or the daily distance from sleeping height.

The main recommendations for preventing altitude sickness are:

  • Do not climb too high too quickly (above 2500 meters a maximum of 300 - 500 meters in altitude per day. Every three days you should take a break)!
  • Choose the lowest possible sleeping height!
  • Never climb further with symptoms of altitude sickness! Escape routes into deeper regions should always be possible.

More tips:

  • Do not cover too great a distance of the daily sleeping height.
  • The walking pace can be based on the rhythm of breathing, for example: Breathe in one step - breathe out two steps or, from around 3,000 meters, breathe in one step and exhale one step.
  • Short daily stages, light payloads and frequent rest during the ascent are recommended.
  • If you know your personal "critical height", you should sleep several nights at this height before starting another ascent. Above the "critical height", the daily difference in height to the next sleeping place should not be more than 300 to 500 meters. If larger distances between the sleeping heights cannot be avoided, two nights should be spent at the same height.
  • Drink enough: Above 2,500 meters, the daily fluid requirement is around three to four liters. If you drink enough, the urine is light and clear. Lack of fluids increases blood thickening. This increases the risk of thrombosis and thromboembolism
  • Ev. after reaching the sleeping height, continue to ascend and descend approx. 100 to 400 meters

Prescription drugs, especially the sulfonamide acetazolamide, can be used to prevent acute mountain sickness. A prior medical prescription and advice are required. Acetazolamide accelerates acclimatization.

Acute mountain sickness: symptoms & therapy

Acute mountain sickness, the most common form of altitude sickness, can develop when a person climbs too quickly and with too much intensity to unfamiliar heights and stays there for more than six hours. Very rarely, symptoms can appear after an hour.

The symptoms include:

  • Headache, mostly on the forehead and temples, rarely on one side or in the back of the head. The headache increases with physical exertion
  • Loss of appetite, nausea
  • Vomit
  • dizziness
  • Fatigue, weakness

Acute mountain sickness is when there is a headache and at least one other symptom related to a rapid rise in altitude. Often the symptoms are strongest after the first night and improve at the same level after a day or two of rest. If there are symptoms of acute mountain sickness and the ascent continues, severe forms can develop.

Altitude headache alone with no other symptoms is not altitude sickness. Possible other causes are, for example, sunstroke, flu-like infection, dehydration, exhaustion, migraines, TIA or stroke.

Therapy for acute mountain sickness

At the first symptoms of acute mountain sickness, you should not climb any further, but instead take a day of rest. If the symptoms persist for more than three days or if they worsen beforehand, a descent is necessary. The descent should be at least 500 meters in altitude or to the last symptom-free sleeping height. Alcohol can make symptoms worse. Children should be carried down if they suspect acute altitude sickness in order to minimize the risk of accidents.

The over-the-counter medications Ibubruf or Naproxen can be taken to relieve headaches. In severe, progressive forms of acute altitude sickness, the prescription drug dexamethasone can provide relief from the symptoms.

High altitude brain edema and high altitude pulmonary edema: symptoms & therapy

Severe forms of altitude sickness are altitude cerebral edema and high altitude pulmonary edema. They can develop from an existing acute mountain sickness or occur independently.

At the first sign, an immediate descent of at least 1,000 meters in altitude or removal is vital. Acute symptoms can be treated with special drugs. The treatment of these severe forms of altitude sickness, which can also occur together, requires special medical knowledge.

High lung edema

High elevation pulmonary edema causes fluid to accumulate in the lungs. It usually occurs in the first two to five days after reaching an altitude above around 3,500 meters. Often there are already symptoms of acute mountain sickness.

Symptoms of high altitude pulmonary edema include:

  • Reduced performance with shortness of breath during exercise
  • Shortness of breath
  • to cough
  • Increased body temperature

The main measures of therapy are

  • Fast, gentle descent (if possible without burdening the backpack) or transport away,
  • Keep body warm,
  • the administration of oxygen,
  • the administration of the prescription drug nifedipine and
  • possibly the use of a so-called overpressure bag.

Elevated brain edema

In high-altitude cerebral edema, lesions of the blood-brain barrier form. The brain becomes increasingly swollen. This life-threatening form of altitude sickness usually occurs at very high altitudes. Already existing severe symptoms of acute mountain sickness are typical.

Symptoms of high altitude cerebral edema include:

  • Uncertainty when walking and standing (ataxia) as a leading symptom as well
  • severe headache that does not get better even with medication,
  • Nausea, vomiting,
  • Dizziness,
  • Impaired consciousness,
  • Visual disturbances, photophobia,
  • Fever,
  • Coma.

The most important measures for therapy are:

  • Quick removal, as deep as possible. A descent on your own should be avoided. Give oxygen if possible.
  • Administration of the prescription drug dexamethasone or comparable drugs.
  • Ev. Use of the overpressure bag.

Whom can I ask?

Altitude medical advice

Before going on a mountain tour or a trip to higher altitudes, you can clarify any health problems and risks of altitude sickness with your doctor. Inform the doctor about existing illnesses and medication that you take regularly. Your previous experiences with complaints at altitude are also important.

Ev. the doctor will recommend further examinations in order to assess your state of health and your performance.

For personal advice on altitude medicine, you can also contact a doctor who specializes in altitude medicine (ÖÄK diploma for alpine and altitude medicine)

You can discuss the following points:

  • How can you reduce the risk of altitude sickness
  • What options do you have to treat yourself in an emergency?

Treatment of acute altitude sickness

Severe, acute forms of altitude sickness are very rare in Europe. In an emergency, they require rapid medical treatment and possibly a removal or recovery from the heights into the valley (European emergency number 112).

You can have complaints that persist even after a stay at altitude clarified by your family doctor (general practitioner).

How are the costs going to be covered?

Rescue: In Austria, the costs for rescue operations by helicopter after sports and leisure accidents in the alpine area can be billed to the patient. These costs can be covered by private insurance, such as those covered by private accident insurance or membership of an alpine club or motorist organization. For rescues abroad, the respective national regulations apply.

Diagnosis and therapy: The e-card is your personal key to the benefits of the statutory health insurance. All necessary and appropriate diagnostic and therapeutic measures are taken over by your responsible social insurance agency. A deductible or contribution to costs may apply for certain services. You can obtain detailed information from your social security agency. Further information can also be found at:

  • Right to treatment
  • Visit to the doctor: costs and deductibles
  • What does the hospital stay cost?
  • Prescription fee: This is how drug costs are covered
  • Rehabilitation & cure
  • Medical aids & aids
  • Health Professions AZ

and via the online guide to reimbursement of social insurance costs.