HIGH ALTITUDE ADAPTATION

Press, Volume XCIX, Issue 29336, 15 October 1960, Page 10

HIGH ALTITUDE ADAPTATION

Hillary Expedition To Make Tests

IBy

Dr. U G. C. PUGH]

KATMANDU. QNE of the aims of the Hillary expedition to the Himalayas is to learn how man can adapt himself to high altitudes.

During the ascent of Mt. Makalu and, if possible, on the summit, we shall make physiological observations, using special equipment. Four of the physiologists in the party are expert mountaineers and should be capable of reaching the'summit if this is at all possible.

During the winter months and on Mount Makalu we shall try to fill some of the gaps in physiological knowledge of life at great heights.

Although a great deal of information exists about the changes taking place in the body during short periods of acclimatisation, much less is known about the effects of a long stay at high altitudes, especially at heights over 18,000 feet.

It is generally thought that 18,000 feet is the limit to which complete adjustment is possible. This view is based upon the findings of the last full-scale physiological expedition to high altitudes, which visited a mining settlement on Auconquilcha in the Andes in 1935.

The party spent several weeks at 18,000 feet, studying themselves and the local miners, and some of them spent 10 days at 20,000 feet. They found that the degree of acclimatisation they achieved fell far short of that shown by the miners.

Andean Miners Sleep The miners preferred to sleep at 18,000 feet and climb every day to work in the sulphur mine at 20,000 feet rather than occupy a camp built for them near the mine. Many climbing parties have spent up to four weeks and one as long as six weeks at about 20,000 feet in the Himalayas, and remained comparatively fit and well. Climbers on Mount Everest and other high mountains have found that partial acclimatisation is possible at least up to 23,000 feet. However, at the same time, there is 'an underlying process of physical and mental deterioration which is the more severe and rapid in onset the higher one ascends above 23,000 feet. No fewer than nine men have cilmbed to about 28,000 feet on Mount Everest without oxygen equipment and have returned safely. None of them has suffered any permanent ill effects from the experience. Their subsequent careers suggest that none could have suffered any permanent ill effects.

Physiological studies carried out on Moust Cho Oyu with Erio Shipton in 1952 in preparation for the Mount Everest expedition the following year produced evidence that high-altitude deterioration was not solely due to lack of oxygen, but also to gross insufficiency of food and fluid all the time spent above 20,000 feet. Attention to these matters as well as the provisions for the first time of efficient oxygen apparatus contributed in no small measure to the successful ascent of Everest in 1953. Seven Months Of Acclimatisation Since then all the great Himalayan peaks exceeding 27,500 feet have been climbed using similar methods, and mountaineers are turning their attention once more to climbing without oxygen equipment.

Realising that the limit of acclimatisation can be reached ohiy by spending much longer at intermediate altitudes than has been customary or, indeed, acceptable, among mountaineering expeditions, the present party will spend about seven months in the region of 17,000-20,000 feet before attempting to climb Mount Makalu, which at 27,790 feet is some 1000 feet higher than any peak so far climbed without oxygen equipment ”

During the winter months our physiological work will be concerned mainly with the functions of the heart, the nervous regulation of breathing and the diffusing capacity of the lungs for oxygen. We shall also have with us two stationary bicycles, one at each hut, with the aid of which it will be possible to measure our work capacity, lung ventilation and the output of the heart at varying intensities of work. As regards the brain, we shall study the special senses of hearing and vision, both of which are impaired during acute exposure to

altitude, and certain aspects of mental function, such as concentration, memory and Dqtigue. Previous experience has shown that small parties under stress do not take kindly tn psychological testing, partly because of the effort involved and party from fear of the results. These sentiments, however, do not-have any place in scientific work. If our mental capacity is impaired, it is important that we should know about it and use oxygen while making scientific .observations. My experience, during a much shorter stay at 20,000 feet, has been that, although work is more tiring than at sea level, difficult tasks can be carried out without

loss at accuracy once they are initiated. However, great effort is involved in beginning a fresh line of work.

Also, because at for&ttulness, one had to be careful to record observations immediately.

Whatever inveizmeot there may be, it does not appear to include some of tiie hitfier functions of tiie mind, such as literary and artistic ability. Witness to this are the dispatches written at greet altitudes by leaders- of Dormer expeditions, and the quality of the paintings and verse produced by certain members of Everest expeditions. Altitude affects different individuals in widely different degrees. If we find that some of the party are beginning to show signs of deterioration, we shell send them to a low’er altitude to rest It may, indeed, be necessary for all of us to go down. The object is to produce the best results and not wear ourselves out by trying to exceed our tolerance. By doing so, one cannot be certain that we would not be running the risk of permanent ill effects. For the same reason, as well as for experimental purposes, we are taking with us a generous supply of oxygen, which will be available Dor the to tir it of sickness and for rescue in the case of accident.

[Copyright, 1960, by Field Enterprises Educational Corporation, publishers of World Book Encyclopedia, Chicago. AU rights reserved. Distributed by Opera Mundi, Paris.]