Why are so many people dying on Everest?

It used to be thought that it would be physiologically impossible to climb Mount Everest with or without oxygen. In 1953 Hillary and Tenzing proved that it was possible to reach the summit with oxygen and in 1978 Messner and Habeler demonstrated it was possible without oxygen. Although Everest has not changed, we now have a better understanding of acclimatisation, improved climbing equipment, and established routes with fixed lines guiding climbers up to the summit. For those climbing with oxygen, the cylinders are much lighter.

It would therefore seem logical that climbing Everest might have become an altogether less deadly activity. However, this year the unofficial body count on Mount Everest has reached 15, the most since the disaster of 1996 when 16 people died, eight in one night following an unexpected storm. An analysis of the death rate on Mount Everest between 1980 and 2002 found it had not changed over the years, with about one death for every 10 successful ascents. A sobering statistic for anyone who reaches the summit is that you have approximately a 1 in 20 chance of not making it down again. So why are there so many people dying on Mount Everest? And more importantly, can we reduce this number?

The main reasons for people dying while climbing Mount Everest are injuries and exhaustion. However, there is also a large proportion of climbers who die from altitude related illness, specifically from high altitude cerebral oedema (HACE) and high altitude pulmonary oedema (HAPE). Usually the cause of death is confirmed by a fellow climber and therefore not entirely accurate, and it is likely that altitude illness may also have contributed to deaths attributed to injuries and exhaustion.

This year I was on the north side of Everest as the doctor on the Everestmax expedition (http://www.everestmax.com/). I was shocked by both the amount of altitude related illness and the relative lack of knowledge among people attempting Everest. Within my own expedition of only 15 people, there were two cases of high altitude pulmonary oedema and one case of high altitude cerebral oedema, which is far higher than the 1-3% incidence predicted. Fortunately all these people made a full recovery.

On our summit attempt we were able to help someone with high altitude pulmonary oedema at 7000 metres, but higher up the mountain we passed four bodies of climbers who had been less fortunate. The last body we encountered was of a Frenchman who had reached the summit four days earlier but was too exhausted to descend. His best friend had tried in vain to get him down the mountain, but they had descended only 50 metres in six hours and he had to abandon him.

Some people believe that part of the reason for the increase in deaths is the number of inexperienced climbers, who pay large sums of money to ascend Everest. However, all the climbers whom I know of who died this year had 8000 metres' climbing experience. In my view, climbers are not climbing beyond their ability but instead beyond their altitude ability. Unfortunately it is difficult to get experience of what it is like climbing above Camp 3 (8300 metres) without climbing Everest. Climbers invariably do not know what their ability above 8300 metres is going to be like.

With cerebral oedema you get an altered sense of reality. This is exemplified by Lincoln Hall, a climber attempting Everest this year, who developed high altitude cerebral oedema on the way down from the summit. After being left for dead he was found by another group of climbers the following day. He believed that he was on a sailing boat. At another point he even got on the radio and started coordinating the rescue, oblivious to the fact that the rescue was actually for him.

On top of the world: author Andrew Sutherland (left) and Sherpa Tshering at the summit

Is it a milder form of this disorientation that allows climbers to deceive themselves that they can still get to the top and down again? I think it is likely that we all develop a certain degree of pulmonary and cerebral oedema when going to the summit and that it is only a matter of time before we succumb to it. Climbers need to think less about “the climb” and more about their health on the way up. No matter what the affliction, whether it be HACE, HAPE, or just exhaustion, the result is invariably the same—the climber starts to climb more slowly. In general your rate of ascent should be no longer than 1-1.5 hours per 100 metres. If you are too slow this means that something is wrong and your chances of not making it off the mountain are greatly increased. However, with the summit in sight this advice is too often ignored.

When I had to visit the French consulate in Kathmandu to confirm the Frenchman's death, the consul, not a climbing or an altitude expert that I know of, shook his head and said, “He didn't reach the summit until 12.30; that is a 14 hour climb—it is too long. All the files we get of those that die on the mountain, c'est toujour la m®me chose [it's always the same thing]—they take too long to reach the summit.”

Climbers need to think less about “the climb” and more about their health on the way up Everest