224 



METABOLISM DURING WALKING. 



CARBON-DIOXIDE ELIMINATION AND OXYGEN CONSUMPTION DURING GRADE WALKING. 



The total carbon dioxide eliminated and oxygen consumed during 

 the grade-walking experiments, as given chronologically in tables 13 

 to 16, show variations for the different periods of the individual days, 

 but when we take into consideration the fact that the speed also varied 

 to a certain extent for the different periods on each day, these variations 

 in the carbon dioxide and oxygen appear to have no general significance, 

 especially as they have no uniform relationship with the variations in 

 the speed. On the other hand, when the data are grouped according 

 to grade and speed, as is done in table 56, we find with any one grade 

 that when the speed increases, that is, when the work performed in- 

 creases, there is likewise an increase in the carbon dioxide and oxygen. 

 We also find that both the carbon dioxide and oxygen with a low speed 

 and high grade are lower than when the same amount of work is accom- 

 plished with a high speed and a low grade. This is also shown in the 

 curves in figures 16 to 19, which are discussed later. 



TABLE 57. Metabolism of W. K. and E. D. B., with maximum amount of work performed. 



(Values per minute.) 



'Work due to grade-lift. See column /, tables 54 and 55. 



2 See Benedict and Cathcart, Carnegie Inst. Wash. Pub. No. 187, 1913, p. 64, table 74, and p. 

 124, table 116. The subject rode a bicycle ergometer. 



3 See Benedict and Murschhauser, Carnegie Inst. Wash. Pub. No. 231, 1915, p. 59. Standing 

 values for same day for carbon dioxide and oxygen (215 c. c. and 246 c. c., respectively) used as 

 base for computing increase for this period, also for March 6, 1912. The subject walked on a 

 level. 



The maximum daily averages for the two subjects who did the 

 largest amounts of work (W. K. and E. D. B.) are given in table 57. 

 For comparison, the maximum performance of M. A. M. on a bicycle 

 ergometer in the study of Benedict and Cathcart, 1 and of the same 

 subject walking on a level in the study of Benedict and Murschhauser 2 

 are included in the table. It should be stated, however, that whereas 

 the values for W. K. and E. D. B. represent an average of data ob- 

 tained in two periods of approximately 10 minutes each, the figures for 



Benedict and Cathcart, Carnegie Inst. Wash. Pub. No. 187, 1913, p. 64, table 74, and p. 124, 

 table 116. 



2 Benedict and Murschhauser, Carnegie Inst. Wash. Pub. No. 231, 1915, p. 59. 



