264 



METABOLISM DURING WALKING. 



Comparing these increases in the pulse-rate with the increases in the 

 oxygen consumption for like amounts of work, we find that with W. K., 

 when he was doing the maximum amount of 891 kg. m. of work, the 

 increase in the oxygen consumption over his standing requirement was 

 818 per cent, and with E. D. B. for 1,569 kg. m., the increase was 1,205 

 per cent. (See table 57, p. 224.) This shows the enormous increase in 

 the oxygen consumption as compared with the increase in the pulse- 

 rate. How this great increase in oxygen consumption is provided 

 for is still undetermined. Certainly, neither the increase in the pulse- 

 rate nor any probable increase in the oxygen-carrying capacity of the 

 blood due to the more complete combination with the hemoglobin can 

 account for it, and an increase in the volume output of the heart, 

 with perhaps a large pulmonary oxidation 1 under these conditions, 

 seems probable. 



TABLE 78. Pulse-rate of W. K. with increasing amounts of work in grade- 

 walking experiments without food. (Values per minute.*) 1 



upon figure 28, p. 258. 



From the curves in figures 28 and 29, estimates may be made of the 

 increase in pulse-rate with increasing amounts of ]work, as was done 

 for the total oxygen consumption, total heat-output, and other factors. 

 These estimates are recorded in tables 78 and 79, together with the 

 increase over the average values for the standing experiments. The 

 percentage increases in the last column of these tables show that with 

 W. K. the pulse-rate increased 14 per cent for each 100 kg. m. of work 

 done over his average pulse-rate of 79 during standing; with E. D. B. 

 the increase over his standing average of 78 was more nearly 10 per 

 cent for each 100 kg. m. The increase in the oxygen consumption on 

 this same basis varied from 139 to 97 per cent for W. K. and from 150 

 to 77 per cent for E. D. B. (See tables 58 and 59, p. 229.) The 

 approximation to constancy in the percentage increase of the pulse- 

 rate with each 100 kg. m. of work is in marked contrast to the fall in 



Henderson, Am. Journ. Physiol., 1912-13, 31, p. 352. 



