Acute Mountain Sickness (AMS), otherwise known as Altitude Sickness, is the effect of high altitude on the human body.
You may remember the preparation of the ‘celebrities’ including Cheryl Cole and Fern Cotton for an ascent of Mount Kilimanjaro and the surprise of the watching public that the apparently overweight Chris Moyles did not experience the extent of sickness at altitude which some of his colleagues did. This illustrates that AMS is frequently unpredictable, and the extent to which you, or your travelling companions, may be affected can’t be reliably determined ahead of time .
This means that everyone reaching altitudes of 2500 metres or more should be aware of the signs which may signal that they are starting to suffer from the effects of AMS, and perhaps more importantly, what can be done to alleviate the symptoms.
Don’t assume that it is only mountaineers who need to be concerned, with a number of lifts in European ski resorts going higher than 3000 metres, you might find you can use it as an explanation for falling over your own feet on your next winter sports holiday!
What causes it?
The simple explanation is, that there is less oxygen in the air you breathe on a mountain, compared to the beach. However for those of you who like graphs and statistics the Altitude.org website has a fantastic altitude oxygen calculator which shows very effectively the difference in oxygen levels in the same person, breathing at the same rate, at any chosen altitude.
Despite knowing this the actual mechanism of the disease itself, and the varied presentations, is actually little understood .
How do I know if I’ve got it?
The initial signs of AMS can be similar to a hangover, or some of the other issues associated with being at altitude such as sun exposure or dehydration.
In general, early stage AMS symptoms include headache, extreme tiredness, nausea and dizziness. In addition sufferers may find that they have some amount of sleep disturbance.
As you can see, many of these things could be put down to simply being more active than usual. Consequently, if you have travelled to altitude, and you or your companions start to complain of similar problems….or entertainingly, start passing wind more frequently and excessively, then care should be taken, and any ascent should be slowed down in order to give the individuals a chance to acclimatise better.
The severe end of AMS include fluid in the lungs, referred to pulmonary oedema, and swelling of the brain, described as cerebral oedema . These serious, and potentially fatal, symptoms are referred to as High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE).
HAPE causes breathlessness, even when the subject is resting. It may also be accompanied by a fever and coughing up unusually frothy spit. HACE may be demonstrated through uncharacteristic behaviours, including violence, alongside general confusion and clumsiness .
Help…what do I do now?
The simple answer is “go down”, or if the symptoms are very mild, slow the ascent fundamentally to see if the individuals can acclimate better.
If a member of your party is starting to show more severe symptoms then a trained medic may be able to administer some drugs which may help, however there is really no other alternative but a rapid descent. In the case of both HAPE and HACE a portable altitude chamber may be used as a temporary measure .
That sounds horrible, so how do I avoid it?
The good news is that avoiding AMS and its more acute effects is also possible if you consider the following “Golden Rules” created by Dr David Shilim and summarised on the Altitude.org website:
1. If you feel unwell, you have altitude sickness until proven otherwise
2. Do not ascend further if you have symptoms of altitude sickness
3. If you are getting worse then descend immediately
If in doubt plan for a slow ascent, stop, or descend if you feel at all unwell, and discuss the potential of taking Acetazolamide (Diamox) with your GP or a suitably qualified and knowledgeable professional in the planning phase of your trip.