100 th Anniversary of the Anglo-American Pikes Peak Expedition

For those of us interested in the history of our discipline, July 12 of this year was a red-letter day. It was the 100^th anniversary of the ascent by cog railway to Pikes Peak by the members of what was the most influential physiological research expedition to high altitude up till that time. Figure 1 shows the participants (from left to right) J.S. Haldane, M.P. FitzGerald, E.C. Schneider, Y. Henderson, and C.G. Douglas with the railway in the background.

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FIG. 1.

Members of the Anglo-American Pikes Peak Expedition of 1911. The cog railway line can be seen in the background.

The choice of Pikes Peak as the venue had an amusing twist. When Haldane from Oxford met Henderson from Yale during the International Congress of Physiology in Vienna in 1910, Haldane stated that what he needed was “a nice comfortable mountain.” This whimsical statement probably followed from the fact that the only two high altitude stations in existence at the time, the Observatoire Vallot on Mont Blanc at 4350 m and the Capanna Margherita on a peak of the Monte Rosa at 4559 m, were both remote, had primitive living conditions, and were very difficult to reach over snow and ice. Haldane's point was that he needed a site where the living conditions were congenial, the temperature was acceptable, adequate food was available, and the only difference compared with sea level was the low barometric pressure. The Summit Hotel on Pikes Peak fulfilled these criteria well. Ascent by rail was easy, several rooms were set aside for the expedition, the laboratory was comfortably warmed, the cuisine was judged excellent, and in addition they were only 14 miles from Colorado College in Colorado Springs where Schneider had a laboratory and supplies were available.

The design of the expedition was classical. First, many physiological measurements were made at sea level and a few at the low altitude of Colorado Springs. The team then ascended rapidly to the summit, altitude 4300 m, where they remained for 5 weeks. Finally, they descended to Colorado Springs and then to New Haven. An important feature of the expedition was that extensive measurements were made during the deacclimatization period. Little information was available at the time about this, and indeed this is still the case to some extent.

The extensive report of the expedition (Douglas et al. 1913) is downloadable from JSTOR and still makes good reading. At 133 pages, the style is relaxed and is in great contrast to some of today's reports which read a bit like falling down stairs. The investigations covered a wide area. All four subjects who remained at the summit developed acute mountain sickness initially, but reported that most of the symptoms had disappeared after 2 to 3 days. A major interest was the arterial Po₂, particularly in relation to the alveolar value. At the time Haldane believed that the lung secreted oxygen, and the expedition reported that the arterial Po₂ averaged 35 mm Hg above the alveolar value. Of course this was an error, presumably related to the indirect method of measuring the arterial Po₂. This was done by having the subject inhale carbon monoxide, and the relations between the partial pressures and concentrations of oxygen and carboxyhemoglobin were then measured. However, this error should not detract from the rest of the important findings. It was shown that over 5 weeks the alveolar Pco₂ fell to about 25 mm Hg, and that on return to sea level it took about 3 weeks to return to normal. Periodic breathing was commonly observed and shown to be abolished by breathing oxygen. A number of measurements of the respiratory exchange ratio were made during both rest and exercise, and the results were as we would expect today. The blood hemoglobin concentration continued to increase for several weeks, and it was recognized that the initial rise was caused by hemoconcentration. Attempts were made to measure the blood inculation rate by indirect methods and these suggested that it was the same as the sea level value after acclimatization. The main factors in the acclimatization process were thought to be oxygen secretion, hypoventilation, and the increased blood hemoglobin concentration.

A colorful feature of the expedition was the involvement of Mabel FitzGerald. As shown in Figure 1, she accompanied the men to the summit, but she did not stay there for reasons that are not completely clear. One story is that this was because she was not chaperoned, but it is more likely that the men thought that the presence of a woman would have complicated the living conditions. So instead of joining the men, she carried out a related study in which she visited various Colorado mining camps alone, accompanied only by a mule. It is difficult to imagine a more hazardous environment for a single woman. Nevertheless, she obtained a large amount of data on alveolar Pco₂ at relatively low and medium altitudes. The measurements were done with a Haldane apparatus that she had used previously at Oxford. Her extensive results were published under her name alone (FitzGerald, 1913) and interestingly are still frequently quoted because so few measurements of alveolar gas concentrations have been made at low and medium altitudes.

A postscript took place in Oxford in 1961 when the Haldane Centenary Symposium was organized to celebrate Haldane's birth in 1860. Suddenly people wondered what had happened to Mabel FitzGerald, someone looked in the Oxford telephone directory, and there she was living near the site of the symposium. She was able to attend and, having surfaced, was given an honorary M.A. degree by Oxford University when she was 100 years old.

The Pikes Peak Expedition was an important landmark in the development of high altitude physiology and medicine. The conclusion on oxygen secretion was erroneous, but the other findings have stood the test of time and if you did not raise a glass on July 12 I invite you to do this now.