Excerpt from TIBET: THE BRADT GUIDE
Michael Buckley, copyright 2018, all rights reserved.
Altitude Sickness
When Sherpas say climbing is in their blood, they may mean it literally. Sherpas have a physiology adapted to the high-altitude environment—their blood has a higher red-cell count, and their lung capacity is larger. Ability to adapt to altitude is thought to be in your genes. That may mean you either have the high-altitude genes or you don't. If you do, you can adapt quickly; if you don't, it will take longer—or so the theory goes. At higher altitudes, air pressure is lower, and the air is thinner. Although it contains the same percentage of oxygen as it does at sea level, there's less oxygen delivered in each lungful of air. So you have to breathe harder, and your body has to convert to more red blood-cells to carry the oxygen through the system.
Altitude sickness is something of a mystery. It does not appear to depend on being in shape: athletes have come down with it, and it may occur in subjects who have not experienced it before. Altitude sickness generally occurs at elevations above 2000 metres, becomes pronounced at 3500 metres, and then requires adjustment at each 400 metres of elevation gain after that.
Terrain above 5000 metres (common enough in Tibet) is a harsh, alien environment—above 6000 metres is a zone where humans were never meant to go. Like diving at depth, going to high altitudes requires special adjustments. To adapt, you have to be in tune with your body. You need to travel with someone who can monitor your condition—and back you up (get you out) if something should go wrong. Consider this: if you were to be transported in a hot-air balloon and dropped on the summit of Everest, without oxygen you would collapse within 10 minutes, and die within an hour. However, a handful of climbers have summited Everest without oxygen: by attaining a degree of acclimatisation, they have been able to achieve this. A similar analogy could be drawn with flying in from Chengdu, which is barely above sea level, to Lhasa, at 3650 metres. That's a 3500-metre gain in an hour or so. You need to rest and recover. Coming by land from Kathmandu, you rise from 1300 metres up over a 5200-metre pass at Tong La—a gain of 4000 metres over a few days (to soften the blow, it would be worth staying a few days at Nyalam, which is 3750 metres).
The study of altitude sickness is still evolving. Recent studies suggest that altitude sickness may be due to leaky membranes—which are more permeable as you up in elevation. It was unknown if a person could survive above 7500 metres without oxygen until 1978, when Messner and Habeler summited Everest. Actually, a hundred years earlier, in 1875, French balloonist Tissandier reached 8000 metres after a three-hour ascent and lost consciousness: the balloon descended and Tissandier survived but his two companions died. Messner was told he would come back from Everest a raving madman, or, at the very least, a brain-damaged automaton if he attempted the peak without oxygen. Messner got his timing right, got to the top, and went on to bag all the 8000-metre peaks without oxygen. Climbers like Messner, however, will admit to impaired functions at higher elevations—and to strange encounters. Messner recalls talking to his ice axe, talking to his feet, talking to an imaginary companion and having hallucinations.
The Buddy System
When you go diving, you use the buddy system. You watch out for your friend underwater, which is an alien environment and a potentially dangerous one. You could draw close parallels in Tibet: high altitude is a dangerous environment. If someone gets altitude sickness, he or she becomes confused or disorientated, and cannot make the right decisions. Someone else has to take those decisions. Back yourself up in Tibet with at least one buddy. And be prepared to watch out for others in a Landcruiser group if someone falls sick.
