Medicine: Way Station to Space

To help them decide what type of man should be chosen to venture into space and how he should be trained, U.S. Air Force researchers turned to people who have been living for centuries at a way station toward space: the Indians of the High Andes. In San Antonio last week, Physiologist Robert T. Clark reported to the Second International Symposium on the Physics and Medicine of the Atmosphere and Space (see SCIENCE) that a valuable lesson has been learned from the Indians at Morococha (pop. 8,500), a mining town in Peru’s central Andean highlands.

At 14,900 ft. elevation, Morococha has an average atmospheric pressure (446 mm. of mercury) slightly more than half that at sea level. But its barrel-chested natives, after generations of exposure to perpetual oxygen shortage, have a lung structure and blood pattern especially adapted to extract full value from the last available whiff of oxygen (TIME, Jan. 20). They literally and habitually work like navvies with nary a huff or puff, even go to 16,000 ft. to “relax” by playing a murderously fast game of soccer.

Key Questions. Key questions for the Air Force researchers were: 1) Would this adaptation help a spaceman to survive if he accidentally lost his oxygen supply, and 2) can a lowly sea-level type achieve the High Andean’s resistance to oxygen deprivation—but in a matter of weeks instead of centuries? Helping Dr. Clark get the answers were Drs. Alberto Hurtado and Tulio Velasquez of Lima’s Institute of Andean Biology.

Since Morococha is not high enough for his purpose Dr. Velasquez put local volunteers into an altitude chamber, exhausted the air until the pressure equaled that at 30,000 ft., then had them take off their oxygen masks. Whereas virtually all unacclimated lowlanders lose consciousness in less than three minutes under these conditions, half the Morocochans were able to take it indefinitely and thus made it possible for Dr. Velasquez to figure out average endurance. The break point came at 32,000 ft. in this experiment; only one volunteer wore down the researchers by failing to black out. The rest did so after an average of six minutes.

Emphatic Yes. Going higher by 2,000-ft. steps, the subjects had progressively shorter times of useful consciousness. But even at 40,000 ft. the Indians averaged 1½ minutes, and one held out for more than two minutes. These results answered the first question with an emphatic yes: an astronaut having temporary trouble would be able to function effectively far longer, and thus perhaps save his life, if he had the High Andean’s altitude endurance.

To the second question, Dr. Bruno Balke supplied a partial answer with rugged training of Air Force volunteers on Mount

Evans, Colo. (TIME, Aug. 25). After nearly six weeks of inching up to its 14,260-ft. peak, airmen could exercise in an altitude chamber simulating 38,000 ft. without getting the bends, and they remained conscious for an average of 30 minutes at 30,000 ft. Drs. Balke and Velasquez took students from sea-level Lima to Morococha, found that after a few weeks they could work as hard as the oldtimers. But the highland natives still had one advantage: their lungs worked only half as hard as the newcomers’ because they were twice as efficient in extracting oxygen from the rarefied air.