Staying at High Altitude

Altitude Sickness

At high altitude, lower oxygen levels in the air can lead to various forms of altitude sickness. Susceptibility varies between individuals, and the most important risk factor is how quickly you ascend to high altitude.

The recommendation is not to ascend more than approximately 300 vertical metres per day at altitudes above 3,000 metres and absolutely no more than 500 metres per day. Faster ascent increases the risk of altitude sickness and reduces the body's ability to acclimatise.

It does not matter whether you are physically fit or well trained – anyone can develop altitude sickness. The risk is greater if you have previously experienced altitude sickness or ascend rapidly to high altitude. Avoid sedatives and sleeping tablets during acclimatisation, as they can affect breathing.

Remember that air travel can take you rapidly to high-altitude destinations such as La Paz (approximately 3,500 m), giving the body limited time to acclimatise.

Preventing Altitude Sickness

  • Consider resting for 1–2 days at an altitude of 2,500–2,800 metres before continuing higher.
  • Ascend gradually and give your body time to acclimatise.
  • Avoid strenuous physical activity during the first few days at high altitude.
  • Drink regularly and avoid dehydration.
  • Avoid alcohol and sedative medicines during acclimatisation.

Climb High – Sleep Low

Above 3,000 metres, you should preferably not sleep more than approximately 300 metres higher than the previous night. You can climb higher during the day but should return to a lower altitude to sleep. It is primarily your sleeping altitude that is important for acclimatisation.

Diamox (Acetazolamide)

Diamox is a medicine that can accelerate the body's acclimatisation and reduce the risk of altitude sickness. It can be used preventively when rapid ascent to high altitude cannot be avoided or in people at increased risk of altitude sickness.

Acetazolamide can also be used as part of the treatment of acute mountain sickness (AMS). Its use should be discussed with a doctor before travelling, particularly if you are planning a trip where rapid ascent to high altitude is difficult to avoid.

Side effects can include increased urination, changes in taste, and tingling or numbness in the fingers, toes and face. Diamox is not suitable for everyone and may be unsuitable for people with certain kidney conditions or those taking certain medicines.

Important Information About Diamox

Diamox should never be used to mask symptoms of altitude sickness so that you can continue to a higher altitude. Never ascend further if you have symptoms of altitude sickness. If your symptoms worsen, descend to a lower altitude immediately.

Mild Altitude Sickness (AMS)

Acute Mountain Sickness (AMS) is common following rapid ascent to high altitude. The risk increases with altitude and, particularly, with the rate of ascent.

Headache is a typical symptom and may occur together with one or more of the following:

  • dizziness
  • sleep disturbance
  • loss of appetite
  • nausea
  • fatigue

Symptoms often develop within a few hours of arriving at a higher altitude and, in mild AMS, may resolve within a couple of days if you do not continue ascending.

If You Develop Symptoms of AMS

Do not continue to a higher altitude. Rest and give your body time to acclimatise. Once the symptoms have completely resolved, you may continue upwards at a slow pace. If symptoms worsen despite rest, descend to a lower altitude.

Severe Altitude Sickness (HAPE and HACE)

Severe forms of altitude sickness can develop at altitudes as low as approximately 2,500–3,000 metres, although the risk increases at higher altitudes and with rapid ascent.

  • HAPE (High Altitude Pulmonary Edema) – fluid accumulation in the lungs.
  • HACE (High Altitude Cerebral Edema) – swelling of the brain.

Life-Threatening Conditions

Both HAPE and HACE are potentially life-threatening and require immediate action and descent to a lower altitude.

Symptoms of HAPE

  • shortness of breath with mild exertion that worsens and may progress to shortness of breath at rest
  • markedly reduced physical performance
  • cough
  • noisy or laboured breathing
  • tightness or discomfort in the chest
  • in severe cases, frothy or blood-stained sputum

Symptoms of HACE

  • severe or worsening headache
  • poor coordination and unsteady walking
  • confusion or changes in behaviour
  • pronounced fatigue or drowsiness
  • vomiting
  • reduced consciousness or unconsciousness

Watch your travelling companions for signs of severe altitude sickness. Confusion, unsteady walking, shortness of breath at rest or a rapidly worsening general condition may indicate severe altitude sickness. The condition can deteriorate rapidly.

What to Do If HAPE Is Suspected

  • Begin descending immediately, if possible by at least 500–1,000 vertical metres or until there is clear improvement.
  • Give oxygen if available.
  • Avoid physical exertion and assist the person during the descent.
  • Keep the person warm.
  • Seek medical attention immediately.

What to Do If HACE Is Suspected

  • Begin descending immediately, if possible by at least 500–1,000 vertical metres or until there is clear improvement.
  • Give oxygen if available.
  • Do not allow the person to walk without assistance if their coordination is impaired.
  • Keep the person warm.
  • Seek medical attention immediately.

Cold and Frostbite

High-altitude travel often also involves exposure to cold conditions. The combination of wind, wet conditions, fatigue and lack of energy can quickly cause cold injuries even when the temperature is above freezing.

Preventing Cold Injuries

  • Wear several layers of clothing.
  • Keep dry and warm.
  • Carry extra clothing.
  • Remember a hat, gloves or mittens, and extra socks.
  • Drink regularly and avoid dehydration.
  • Eat enough to maintain your body's energy reserves.
  • Keep moving to stay warm and maintain circulation.
  • Seek shelter in bad weather.
  • Avoid alcohol.

Wind Increases the Effect of Cold

Wind can make conditions feel considerably colder than the temperature shown on a thermometer. The combination of cold, wind and damp clothing significantly increases the risk of hypothermia and frostbite.

Superficial Cold Injury

A superficial cold injury may cause numbness, tingling or pain and pale skin that still feels soft.

Protect the area from further cold and warm it gently, for example against a warm part of the body. Do not rub or massage the skin.

Deep Frostbite

With deep frostbite, the skin may become hard and numb and later develop swelling, discolouration and blisters. Severe injuries can lead to tissue death.

Do not thaw a severely frostbitten body part if there is a risk that it may freeze again. Thawing followed by refreezing can cause further tissue damage.

When refreezing can be prevented, the frostbitten body part should be rapidly rewarmed in water at a temperature of approximately 37–39 °C. Rewarming can be very painful. Give appropriate pain relief if needed and seek medical attention as soon as possible.


Senast uppdaterad 2026-09-06