Life in the clouds can be far from heavenly. Above 2,200 metres, the amount of oxygen in the air decreases and the body must try to adjust. At 3,600 metres, there are roughly 40% fewer oxygen molecules per breath than at sea level. In extreme cases, usually above 5,000 metres, this can cause a loss of fluids from capillaries in the lungs and brain, which can lead to a fluid build-up (pulmonary or cerebral oedema).
On the upside, a lack of oxygen can bring on fits of giggles. Less fun are common symptoms of Acute Mountain Sickness (AMS), such as nausea, shortness of breath, poor coordination, disrupted sleep, pounding heart and paranoid feelings. Follow these rules to avoid (or at least reduce) symptoms…
1 Almost all altitude sickness stems from going too high, too fast. After 3,000m, ascend only 300m a day and then rest for a day.
2 Over-exertion is a key cause of altitude sickness. If, for example, you fly into Chile’s Atacama Desert, take it easy for at least 24 hours.
3 Breathing 100% oxygen (from a canister) can reduce the symptoms, but the only cure is acclimatisation or descent.
4 Avoid alcohol, coffee, tobacco and depressant drugs (like sleeping pills). They lower the respiratory drive and worsen symptoms.
5 Symptoms can be reduced by descending by as little as 300m and waiting for 24 hours or until you feel better.
6 High altitudes are often accompanied by fluid loss. If you’re not peeing very reguarly, you’re not drinking enough.