Altitude sickness

What is altitude sickness?

Altitude sickness, also known as acute mountain sickness, is a condition that’s caused by the body’s inability to get enough oxygen. It can become a serious threat to your health if it’s not treated promptly, although most people make a full recovery.

It occurs at altitudes where the oxygen is thinner, making it harder for the body to process it. Thankfully, there are many ways it can be avoided with careful planning.

Who gets altitude sickness?

Anyone can develop altitude sickness. Unlike many conditions, age, gender and health rarely have an impact on the condition, so no one group of people are more likely to suffer from it than another. Having suffered from it before will also not lessen the symptoms of the condition or the likelihood of you experiencing it again.

The biggest risk of getting altitude sickness comes from a lack of preparation. It’s vital if you know you’ll be in a high altitude environment that you put in place measures to avoid the condition and treat it, should it develop.

How common is altitude sickness?

The likelihood of experiencing altitude sickness relates to the altitude you are in. For example, it’s very unlikely you’ll experience the condition in the UK because the highest peak is under 1,500m. Altitude sickness usually occurs at heights of over 2,500m.

It’s also important to note that you are just as likely to experience it in a city, such as La Paz in Bolivia, as you are climbing a mountain. In fact, as the change in altitude happens more quickly after a flight, travelling to a high altitude city can increase the risk of the condition occurring.

If you’re going to be at altitudes of over 2,500m, you’re likely to experience at least some mild symptoms. These risks can be reduced with careful planning.

What causes altitude sickness?

Altitude sickness is caused by a lack of oxygen in the body, which itself is caused by the thinning of oxygen levels that develop the higher up you go. And it’s worse if you haven’t taken the time to acclimatise to the new altitude.

The first symptom you might notice is difficulty breathing, which can be a particular problem when combined with physical exertion, including climbing a mountain.

How to avoid altitude sickness

There are many ways to avoid altitude sickness,^[1] or at least minimise its risks. These include climbing slowly so the body can adjust to the changes in oxygen levels, resting regularly if you’re on a steep climb, and stopping climbing for an entire day every few days if the altitude is particularly steep.

You should also avoid becoming dehydrated, avoid alcohol or smoking, and eating heavy meals, although they should remain high in calories if you’re climbing.

What are the symptoms of altitude sickness?

It can take a few hours for the symptoms of altitude sickness to present. This means that even if you have made your descent, you might continue to feel its effects. You’ll usually start to feel symptoms after six hours, but it can take at least a day.

Symptoms have been compared to those of a bad hangover, including headaches, dizziness and nausea. You might also experience a loss of appetite, shortness of breath and general fatigue.