What is altitude sickness?

Causes, symptoms and treatment


Altitude or high altitude sickness occurs when someone climbs a mountain quickly into a different pressure. The drop in atmospheric pressure prevents you from taking in adequate oxygen and leads to difficultly in breathing. Most instances of high altitude sickness are not severe and result in headaches, dizziness and some nausea. In some cases, there is a possibility of fluid build-up in the brain or the lungs which can be extremely dangerous.


There is no clear understanding behind why some individuals to experience altitude sickness. Yes, we do know travelling to an area of high altitude is a factor, but it is impossible to point out who will be affected by it. Gender, age, physical well-being and the presence of other medication conditions do not seem to factor into whether will experience altitude sickness. However, obesity is one factor linked to the increased risk of suffering from altitude sickness.

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We do have an understanding of why altitude sickness occurs. The air is thinner at higher altitudes meaning there are fewer oxygen molecules per breath inhaled. This reduced atmospheric oxygen causes your heart to work harder to provide all your vital organs with sufficient oxygen. This excessive strain on your heart can result in a variety of problems, manifesting in symptoms commonly associated with altitude sickness.

Your body may naturally adjust high altitude and sickness after a while, and when it does, the symptoms should resolve on their own.


The most common symptom associated with altitude sickness is a headache. It’s a throbbing pain in the head that persists until your body adjusts. It tends to worsen at night or upon waking.

You may also experience stomach pain or a loss of appetite. Your body is trying to acclimatise to the environment and deal with the lower oxygen levels, which can affect different body systems. Other common symptoms are also dizziness and tiredness. You may feel lethargic, even actions as simple as getting out of bed or eating will prove difficult.

In very severe cases, you may notice colour changes of your nails and lips, turning blue or black. Altitude sickness may also affect your lungs and brain, which may result in difficulty breathing or confusion. HAPE (high altitude pulmonary oedema) affects the lungs and can occur with or without warning symptoms. HAPE is a condition that results in fluid build-up in the lungs. HACE (high altitude cerebral oedema) affects the brain in which extra fluid accumulated in the brain, causing swelling and may cause the brain to stop functioning correctly. More severe symptoms are coma and death. 

Altitude sickness symptoms should not be taken lightly, since some cases can result in fatal illnesses.


Altitude sickness can affect people in different ways, and individuals will suffer from different symptoms or different levels of sickness. Treatment, however, can be equally successful for anyone.

If your symptoms are mild, it acceptable to stay at the same altitude to allow your body to adjust. Your symptoms should resolve on their own after some time. If you are having a severe reaction to the altitude, then it's a good idea to move to a lower altitude. However, it is important to do this slowly to allow your body to deal with the changing pressure. If you don't have that option, then a doctor may prescribe medication such as aspirin or Ibuprofen. These medications can treat some of the painful symptoms. However, others may be prescribed with Acetazolamide, a drug that will help your body to adjust to the altitude quicker.

If no medication is available and you can't leave your current altitude, you should try oxygen treatment. Providing your body with more oxygen should be sufficient in helping your symptoms resolve and allow your body to return to normal.

For people who are spending a long time in a high altitude location and are having difficulty coping, the best thing they can do is to take things at a slower pace. Try not to exert yourself and cause an increase in your body's oxygen demand. Just pace yourself and slowly work your way up to normal levels of activity until your body gets used to the high altitude.

If you know that you will be spending an extended amount of time at a high altitude, it is a good idea to be prepared. One of the best ways to do this is to spend some time at a medium-altitude, permitting your body to adjust naturally to the higher altitude and thus prepare your body for the higher altitude in a less demanding way.

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