258 



METABOLISM DURING WALKING. 



and speed of walking, and not according to the sequence of the experi- 

 ments. As a rule, the changes in the rates progressed gradually and 

 uniformly with the increase in the speed and the amount of work per- 

 formed. The maximum rate was found with the maximum work with 

 each subject, although this is not true of the minimum amount of work. 

 The difference in the respiration-rates for the different subjects is 

 noticeable. At the medium speed of 60 to 65 meters per minute with a 

 10 per cent grade, T. H. H. had a low rate of 17.9 as compared with 

 W. K.'s rate of 26.1; E. D. B. had a rate of 26.7 when walking on a 25 

 per cent grade at 70 to 75 meters per minute as compared with W. K.'s 

 rate of 40 under similar conditions. 



p 



180 



170 

 160 

 150 

 t40 

 130 

 120 

 110 



FIG. 28. Pulse-rate, respiration-rate, and 

 pulmonary ventilation of W. K. during 

 grade walking, referred to kilogram- 

 meters of work. (Values per minute from 

 table 56.) 



The'/curves for the average respiration-rates for W. K. and E. D. B. 

 in table 56 have been plotted and presented in figures 28 and 29. The 

 curve for E. D. B. shows a uniform rate of increase, but that for W. K. 

 indicates a greater rate of increase beyond 300 kg. m. From these 

 curves an estimate has been made of the respiration-rates per minute 

 for increasing amounts of work. (See second column of tables 74 and 

 75.) From these values have been calculated the total and percent- 

 age increases in the respiration-rate over the standing requirement, 

 and also the increments per 100 kg. m. as the unit of work done. The 



