MUSCULAR WORK AND THE RESPIRATORY 



QUOTIENT 



SERGIUS MORGULIS 



All investigations of the physlology of muscular work aim at a 

 Solution of two fundamental problems : the organism's mechanical 

 efficiency and the source of the energy of the working muscle. One 

 is a Problem in animal calorimetry; the other, in metabolism of 

 matter. Since the respiratory quotient, or ratio between the carbon 

 dioxid exhaled and the oxygen consumed, indicates the nature of 

 the material oxidized in the organism, the gaseous metabolism offers 

 the best means of determining the source of energy in muscular 

 work. 



Chauveau, on the basis of his experiments (which unfortunately 

 have never been described in detail and in which the respiratory 

 quotient was observed to increase from 0.75 to 0.95 during stren- 

 uous exercise), advanced the hypothesis that glycogen is the source 

 of muscular energy. To account for all the facts, Chauveau was 

 obliged to postulate further that, as the glycogen is consumed, new 

 quantities are supplied to the muscles, such added quantities being 

 formed from fat by direct chemical change. This hypothesis met 

 Prof. N. Zuntz's sharp criticism on theoretical as well as experi- 

 mental grounds. First, the high respiratory quotient in Chauveau's 

 experiments is obtained at a stage, of the exhausting work, which is 

 so far advanced that it is reasonable to believe that by that time the 

 glycogen would be entirely used up. Furthermore, a transforma- 

 tion of fat into glycogen sufficiently to supply the necessary energy 

 for muscular contraction would beaphysiologicallywastefulprocess, 

 as nearly a third of the potential energy would thereby be lost to the 

 organism. 



Unlike Chauveau, Prof. Zuntz and his students in their numer-? 

 ous researches found the same respiratory quotient before and dur- 

 ing work. In one of the last issues of Oppenheimer's Handbuch 



435 



