THE METABOLISM IN HIGH ALTITUDES 229 



THE METABOLISM IN HIGH ALTITUDES 



The observations of Loewy and Zuntz show that dwelling at 

 lofty altitudes greatly stimulates the metabolism at any rate of 

 untrained town-dwellers. In Alpine soldiers inured to mountain 

 life U. Mosso failed to find any increased C0 9 output. The in- 

 creased metabolism is due neither to insolation nor to the cold 

 and light of the snow-fields, for it persists while the subject rests 

 within the Alpine hut. 



The following figures give the respiratory exchange of Zuntz at 

 Berlin and on Monte Rosa. His weight was 67-6 kg. : 



The respiratory exchange while resting worked out on the 

 average 15 per cent, more on Monte Rosa than at Berlin. This 

 increase began on the second day 1 and lasted during the three 

 weeks' stay in the hut. In Zuntz's expedition of 1901 the stay 

 was only one week, and the increase then was no less than 35-50 

 per cent. Not only the resting metabolism, but that on walking 

 was markedly increased. A slow walk on Monte Rosa exceeded 

 the oxygen used in Vienna during a fast walk (under the same 

 conditions of snow, level, &c.) by one-quarter. Part of this 

 increased metabolism must be attributed to the increased 

 internal work of the body, the heart and respiration to- 

 gether striving to maintain an adequate oxygen tension in the 

 blood. The greater rapidity of the circulation may increase the 



1 This probably explains why increased metabolism has not been observed in 

 the pneumatic chamber experiments or balloon expeditions which only last 

 a few hours. 



