Climbing To The Roof of The World Without Oxygen Support: what helps?
On top of Everest (8,848 m) there is so little oxygen in the air that it barely permits human survival. Thus, reaching those altitudes without the help of supplementary oxygen is a very difficult task.
Nevertheless, since the first ascent of Italian climbers Messner and Habeler in 1977, several climbers have successfully ascended without the aid of supplementary oxygen.
How is it possible?
It is believed that climbers should breath more and more to sustain the progressive lack of oxygen encountered on climbing, and the more they do, the higher their chances of success.
This concept has been recently challenged by a research team from the Universities of Pavia (Italy), Regensburg (Germany) and Ferrara (Italy) during the Italian Expedition to Everest and K2 aimed at celebrating the 50th anniversary of the Italian conquest of K2.
By testing eleven climbers at sea level and after two weeks of acclimatisation at the Everest base camp in Tibet (5,200m), they have found that the climbers who eventually reached the summit of Everest, K2 or both, without oxygen support, were breathing less during acclimatisation, in response to the lack of oxygen, than those who either did not reach the summit or needed oxygen.
What is the explanation of this counterintuitive finding?
"Successful climbers, rather than breathing 'more' were breathing 'better'", says Luciano Bernardi from the University of Pavia. "They developed far more efficient breathing during acclimatisation, so they could breathe less and still get enough oxygen from the air. Therefore, when the lack of oxygen became extreme they still had some capability left to breath deep enough (though not excessively) to be able to reach the summit, whereas the others had perhaps reached their maximal breathing capability at a lower altitude, being thus forced to abandon or use oxygen."
This experience suggests that optimising breathing efficiency could help in coping with the lack of oxygen even at sea level (as in several cardiovascular and respiratory diseases).
Techniques which help to improve breathing efficiency, like yoga, can be used for this purpose.
Title of the original article: Hypoxic ventilatory response in successful extreme altitude climbers.