Acute mountain sickness (AMS) can strike anyone, from professional to amateur mountaineer, and often hits quickly and unexpectedly. And you don’t have to be climbing an eight-thousander for it to strike. Athletes can be affected even on 3,000m peaks in the Alps or when cycling across mountain passes. In this article, we’ll give you an overview of the symptoms as well as how to recognise and treat the condition.
Altitude sickness: the symptoms
A distinction is made between acute mountain sickness (AMS), high-altitude cerebral edema (HACE) and high-altitude pulmonary edema (HAPE). Below, you can find the main symptoms for each to differentiate the conditions.
However, all three conditions have common factors that significantly increase the risk:
- the absolute altitude
- the speed of ascent
- insufficient acclimatisation
- individual predisposition
When assessing the risk for one of the altitude diseases, it is important to consider the ascent profile (how many meters of altitude are to be covered), the sleeping height and past individual susceptibility.
Symptoms of acute mountain sickness (AMS)
- loss of appetite
The most common form of altitude sickness is acute mountain sickness (AMS). The most common symptom is a headache. In addition, there are usually unspecific symptoms such as a general feeling of illness, dizziness, loss of appetite, nausea and insomnia. Acute mountain sickness manifests after min. 4 – 6 hours from an altitude of 2,000 to 2,500 m.
Acute mountain sickness is often most pronounced after the first night at high altitude. Intensive physical exertion such as long, technical ascents further intensify the symptoms. If the patient doesn’t ascend any higher and rests, symptoms generally disappear in 24 to 48 hours. However, the danger increases if they continue to ascend despite existing symptoms – and acute mountain sickness develops into high-altitude cerebral edema (HACE). Then, they must descend immediately.
It is important to listen to your body and pay attention to any changes. It is equally as important to observe your companions when you are not travelling alone. Is my long-time mountain buddy just tired? Or are they moving a lot slower than normal? A noticeable loss of performance at altitude and the first signs of acute mountain sickness are usually noticed more quickly by others in the group, so that countermeasures can be taken early on.
Symptoms of high-altitude cerebral edema (HACE)
- severe headache
- signs of paralysis
- loss of consciousness, up to coma
Symptoms of high-altitude pulmonary edema (HAPE)
- significant loss of performance during ascent
- dry chesty cough
- shortness of breath
- cyanosis (blue colouration of mucous membranes and lips)
- crackling noise when breathing
An early symptom and warning sign of High Altitude Pulmonary Edema (HAPE) is an excessive loss of performance during the ascent, often accompanied by shortness of breath and, initially, dry coughing. High-altitude pulmonary oedema develops after very rapid ascent to altitudes above 4,000m in a period of 2-3 days.
How can altitude sickness be prevented?
The most sensible way to reduce the risks of altitude sickness is a slow gain in altitude as well as being sufficiently physically fit for the tour. Sleeping lower than you have ascended during the day is also important for effective acclimatisation.
If you know you are susceptible to mountain sickness, you should aim for no more than 500 m ascent per day above 2,500 m during trekking and (hut) hikes. If you have been susceptible on previous tours, you should also avoid ascending quickly (e.g. on a cable car) to heights above 3,000 m. Symptoms often only appear on arrival at the hut.
Before undertaking a trekking tour in mountains such as the Himalayas or the Andes, it is also advisable to stay overnight in the Alps above 3,000 m.
How is altitude sickness treated? Are there medications?
The most effective treatment for the symptoms is to improve oxygen supply. This is most easily achieved by descending to lower altitudes. If there are indications of cerebral edema (HACE) or pulmonary edema (HAPE), you must descend immediately! In most cases, this requires a reduction in altitude of 1,000 metres in order to significantly alleviate symptoms.
Mild symptoms of acute mountains sickness (AMS) often disappear within 24 to 48 hours after the onset of the disease, if you rest and undertake symptomatic treatment (drink lots of water!).
When staying at high altitudes, in areas with no infrastructure or in technically demanding terrain, it is often not possible to descend immediately. If necessary, the use of medication can temporarily relieve the symptoms and in the worst case even save lives. However, medication should only be administered by doctors or mountain guides trained in high altitude medicine! Therefore, this article will not go into any more detail about medication for altitude sickness.
Coca tea in the Andes
In the Andes, locals swear by coca tea. To make it, hot water is poured over the leaves of the coca plant. The mountainfolk in the Andes mix the plant with chalk or ashes as a to produce something between chewing tobacco and chewing gum and it is very popular. Firstly, because coca dispels hunger, fatigue, stomach-aches and headaches as well as the cold. But also because coca is effective against altitude sickness.
In fact, the leaves seem to increase oxygen uptake in the blood. However, the plant is also used to produce cocaine, which is one of the reasons why the plant cannot be purchased in Germany.
Oxygen deficiency and the symptoms
Hypoxia is the medical term for lack of oxygen. Hypoxia specifically refers to the lack of oxygen in the body’s arterial blood. Characteristic symptoms of oxygen deficiency are:
- changes in breathing
- acceleration of pulse
- chest pain
Mental symptoms such as spontaneous euphoria, delirium and feelings of lightness can also indicate a lack of oxygen. Dizziness, weakness and general discomfort are also among the most common symptoms when on the mountain.
If body tissue is undersupplied with oxygen for a longer period of time, it can lead to weakened circulation and ultimately, loss of consciousness. Another symptom is nausea without any actual digestive complaint. Manifestations of an oxygen deficiency can come to light in many different ways. Particularly deceptive: the typical complaints are usually unspecific symptoms, which can also be signs of numerous other diseases.
A few closing words…
In summary, altitude sickness can be an extremely life-threatening situation. For those who are susceptible and predisposed, the first symptoms can appear at an altitude of about 2,000 m. With slow acclimatisation and careful preparation, the occurrence and possible symptoms of the disease can often be alleviated, if not completely prevented. However, acclimatisation only works up to a certain point. That’s why you often hear about the so-called ‘death zones’ on the seven and eight-thousanders – areas on the mountain where the body literally begins to die and which no acclimatisation, no matter how perfect, can prevent.
Specific preparation, physical fitness and a slow ascent remain the best measures for healthy trekking and mountaineering at high altitudes. The motto “climb high, sleep low” is the definitive mantra of all mountaineers who want to get up high.