This summer, to escape the high heat, you turned to the mountains. But the miracle solution turned into hell because of nausea, headache, dizziness that suddenly appeared to you once you reached your destination. You may be suffering from acute mountain sickness (AMS). What are the risks ? Will it pass? When to give up the climb? Explanations according to MSD Manual information and of the Research Institute of Health Medicine and Sports Wellness (IRBMS).
What are the symptoms of acute mountain sickness?
Altitude sickness could look like many things: like drunkenness for example, but also make you think of a migraine or even a viral illness. It unfolds under many symptoms such as nausea, vomitingloss of appetitedizziness, headaches or even migraines (90% of cases), feeling tired, or loss of sleep (70% of cases), weakness, nosebleeds, or even irritability.
There are other symptoms, which can be impressive but are not serious: retinal hemorrhages (which, if they persist or prevent you from seeing, require you to go down again), or even a swelling of the hands, feet, facewhich disappear when we go down.
What causes altitude sickness? At what altitude?
Altitude sickness is divided into levels: between 0 and 1,000 meters, there is no reaction. Between 1,000 and 2,000 meters, physical efforts can become more complicated if you are not a regular athlete. From 2,000 meters and up to 5,500 meters, altitude sickness can occur even when stopped, without doing any physical activity. Beyond this altitude, you feel the effects permanently and it is necessary to acclimatize.
This is because the atmospheric pressure drops as you go up. There is simply less oxygen available in the air for the human body, “forcing it to adapt with hyperventilation and the production of red blood cells creating polycythemia and an increase in heart rate at rest and during exercise”, notes the IRBMS. At sea level, the oxygen level is 100. At 1,000 meters, it drops to 88%, then 78% at 2,000m, 69% at 3,000m, 60% at 4,000m.
How long does it last, how do you manage it?
In general, altitude sickness goes away on its own. It can last between 24 hours and 48 hours. To avoid it, there are solutions: like climbing slowly. For example, “Above 3,000 meters, climbers and hikers should not increase their altitude to sleep more than 300 to 500 meters per day, and they should include a rest day (sleep at the same altitude) every 3 or 4 nights before sleeping at any higher altitude,” notes the MSD Manual.
It is also advisable to do not exert physical effort for 2 days after reaching a place at high altitude, to give yourself time to acclimatise. Certain consumptions are to be avoided, such as alcohol, opioids or sedatives. There are treatments to help cope with the altitude, such as acetazolamide, to be taken the night before the ascent, or dexamethasone.
What are the warning signs? What are the risks ?
Sometimes the altitude sickness continues, and escalates into what is called high altitude cerebral edema (OCHA). The MSD Manual states that it is a “rare, but life-threatening condition in which the brain fills with fluid and swells.” In this case, the symptoms are different: the headaches are accompanied by confusion, an unsteady gait, which loses coordination. The progression of this edema is rapid (a few hours), and puts the subject at risk of falling into a coma. SO, at the first signs of this type, it is important to react by calling for help and descending as quickly as possible.
The other risk is pulmonary edema (OPHA), which “refers to an accumulation of fluid in the lungs that typically develops within 24 to 96 hours after a rapid ascent above 2,500 meters,” according to the MSD Manual. The symptoms are a dry cough, rapid shortness of breath or at rest, the skin, nails or lips, which take on a blue tint. If it gets worse, the person may develop respiratory distress, coughing up blood… Again, this can happen in a few hours and lead to coma.
Sources: MSD Manual, IRBMS.
