If you are used to hiking in the high mountains, you have certainly heard of altitude sickness. You may even have experienced it yourself during a high-altitude hike because it is a common annoyance in the mountains. It potentially affects everyone from infants to the elderly, and the first symptoms generally appear around 2000m altitude.
It is now well documented by medicine whether the ailment is mild or acute. Also, you can prevent the appearance of the first symptoms by respecting a few rules.
Finally, the solutions to cure it are numerous and easy to implement. Focus on my comprehensive guide on How to deal with altitude sickness while hiking.
Explanation of Altitude Sickness
Altitude sickness rarely affects people living at high altitudes because their bodies are used to the decrease in oxygen. On the other hand, it frequently happens from an altitude of 2000m on people who climb quickly without going through the stage of acclimatization stages.
Letโs see together what medicine says about it and what its symptoms are.
Medical Definition
According to the MSD manual of medicine, โaltitude sickness is due to the lack of oxygen experienced at high altitudesโ. You probably know that the higher you go, the lower the atmospheric pressure.
However, the concentration of air also decreases, which is why you have more difficulty breathing as you climb to the top of the mountain (see figure 1).

Thus, altitude sickness usually appears around 2000m altitude when you only have access to about 80% of the usual oxygen level. From 2500m, 20% of people develop altitude sickness. This rate even reaches 40% at 3000m altitude and 90% above 5300m altitude.
Common Symptoms
You are starting to develop altitude sickness if, during your hike, you experience these symptoms:
- Headache
- Fatigue
- Loss of appetite
- Nausea, difficulty swallowing
Note that the symptoms appear between 4h and 12h after your arrival at a high altitude. A shorter trip to the top of a mountain will not allow these symptoms to develop. Thatโs why you donโt get altitude sickness when you take a cable car and come right back down!
The Most Serious Cases
The longer you stay at altitude, the more you will accentuate your altitude sickness if nothing is done. In some cases, this disease can be dangerous or even fatal.
Here are the most serious symptoms that can occur:
- Irritability and dizziness
- Discomfort
- Coma
- Cerebral and pulmonary edema
Of course, cases of acute altitude sickness are extremely rare at an altitude of 2000-3000m but become more common above the famous limit of 5300m altitude. But donโt worry, because it is possible to prevent this common evil or even to cure it when serious forms are to be feared.
Some Tips to Prevent Altitude Sickness
It is by knowing the aggravating factors that you can prevent the development of altitude sickness. You may not be able to prevent it from happening, but you will lessen its effects and avoid experiencing severe altitude sickness.
Here are the factors of the appearance of this evil:
- A high-altitude climb too fast without making adaptation stages
- Excessive physical activity at high altitudes
- Too low a concentration of red blood cells in your blood due to your daily life near sea level
- Previous altitude sickness
Based on these observations, it is easy to prevent altitude sickness with a few adapted behaviors:
- Do not climb from 0m to 3000m altitude in a few hours or do not stay more than 4 hours on site.
- Make adaptation levels from 1500m altitude, staying 2 or 3 days on site. This will promote the creation of red blood cells to increase the distribution of oxygen in the body.
- Restrict your movements to what is strictly necessary from an altitude of 2000m in order to save your oxygen and your energy.
- Avoid drinking alcohol or taking sleeping pills, which increases the risk of the onset of mountain sickness.
- Taking prescription medication: If your doctor thinks it is necessary, he or she may prescribe a medication called Diamox, which will help your body acclimate more easily to the lack of oxygen. Available on prescription, it is recommended for people who have already suffered from acute altitude sickness but also to prevent edema and sleep disorders. Like any drug available on prescription, Diamox must be ingested on the advice of your doctor. Avoid any self-medication that could be dangerous.
As soon as you arrive at a high altitude, at 3000m, I do not recommend climbing more than 500m per day in order to give the body time to adapt to the new conditions. Every 3 days, plan to spend 2 nights in a row at the same altitude so that you can avoid rushing your body.
Finally, avoid paracetamol-based medications such as Doliprane, which mask the symptoms of altitude sickness but do not cure it in any way!
Acute Altitude Sickness: How to Eliminate the Symptoms
After seeing together the prevention of altitude sickness to prevent it from appearing, we will look at how to stop this evil when the first symptoms appear. In any case, it is necessary to prevent mild altitude sickness from turning into an acute one, which can be fatal.
First Reflex: Stop the Ascent
It sounds obvious, but many hikers ignore the warnings their body sends them. As soon as the first symptoms appear (migraine and great fatigue), you must stop your ascent in its tracks. The appearance of these symptoms is a sign that your body is suffering from the lack of oxygen.
By continuing to climb, you would put him in more danger and promote the appearance of more serious symptoms such as malaise and nausea.

Step Two: Rest
Fortunately for us, our body knows how to acclimatize to new and difficult conditions. When symptoms appear, take rest to give your body time to produce red blood cells necessary for the transport of oxygen. Set up a tart at your own pace without rushing your body; then wait between 12h and 3 days.
After this time, you have two possibilities: either the symptoms persist, in which case you will have to descend, or they have gone away and you will be able to continue the ascent carefully. For the second hypothesis, think of the system of levels of 500m per day!
Third Step: The Need to Come Down
Despite these 3 days of rest, the symptoms persist. Worse, they get worse sometimes. You must then descend a minimum of 500m to help your body catch its breath. Then take a rest and wait again for 12 hours.
If it doesnโt improve, youโll need to descend to low altitude to seek medical attention. If he/she deems it necessary, he/she can prescribe medication that will help reacclimate your body and make the symptoms of altitude sickness disappear within a few days.
Finally, in the event of significant edema, the emergency services will be able to treat you based on corticosteroids and calcium channel blockers to reduce your swelling. In any case, taking such drugs without going down would be useless!
FAQs: How to Deal with Altitude Sickness While Hiking
What is the best cure for altitude sickness?
Treat Altitude Sickness
- Stop and rest where you are.
- Donโt go higher for at least 24-48 hours.
- If you have a headache, take ibuprofen or paracetamol.
- If you feel sick, take medicine like promethazine. Be careful, not to mask the symptoms to start again better, stop at least 24 hours!
- Make sure you drink enough water.
- Do not smoke, drink alcohol or exercise.
How long does it take to recover from altitude sickness?
Symptoms of moderate altitude sickness usually improve within 24 hours at an altitude below 1000 meters. Symptoms should disappear completely within 3 days. People suffering from acute altitude sickness should be immediately taken to an altitude below 1200 meters.
Does drinking water contribute to altitude sickness?
It is important to stay hydrated at altitude. Symptoms of dehydration are similar to those of altitude sickness. Count one liter to one and a half liters of additional water per day at altitude.
In this case, I recommend you bring a good quality filtered water bottle. Clear urine indicates adequate hydration, dark urine suggests dehydration and the need to drink more water.
How serious is altitude sickness?
Dizziness, nausea, headache, and shortness of breath are some symptoms of this disease. Most cases of altitude sickness are mild and heal quickly. In rare cases, altitude sickness can become severe and lead to lung or brain complications.
Conclusion
Altitude sickness is not a problem to be taken lightly. It affects anyone who does not live at high altitudes all year round when you climb too quickly or do not respect the acclimatization stages. As I mentioned previously, it generally appears from 2000m and becomes frequent above 3000m altitude.
The most common symptoms are headache, fatigue, and irritability. As soon as they appear, it is necessary to stop the ascent, take a rest or descend 500m to recover. Otherwise, an acute syndrome may manifest, with malaise, coma, or even death in the most serious cases.
But this well-known disease is not inevitable: performing the stages, avoiding intense physical activity, and climbing cautiously prevent its appearance in most cases. Be careful during your hikes and donโt hesitate to consult a doctor before and after a high-altitude ascent!