96 METABOLISM DURING WALKING. 



and it is believed that they are eliminated in averaging. The data 

 show a tendency for the quotients in the first periods of the day to 

 run a little higher, possibly, than in the succeeding periods, although 

 the number of such periods is not sufficient to make any deduction 

 therefrom justifiable. The respiratory quotients for the 71 days with 

 E. D. B. have an average daily value of 0.84 in the period from October 

 4 to December 22, 1915, as compared with 0.82 during the period 

 from March 1 to April 15, 1916. On February 23, the day following 

 his most severe walking test with an oxygen consumption of 3,132 c. c. 

 per minute (see table 16, p. 86), there was a marked fall in his respi- 

 ratory quotient, which may have been due to the after-effects of the 

 vigorous exercise of the preceding day. Zuntz and Schumburg 1 and 

 Durig 2 have noted that the respiratory quotients tend to fall during 

 periods of exercise and that this effect is also apparent on the following 

 day. The respiratory quotient of February 23 is, however, based on 

 but one period. (See table 6, page 50.) 



The average respiratory quotients obtained with these five men in 

 the standing positions are as follows: A. J. 0., 0.84; H. R. R., 0.77; 

 T. H. H., 0.86; W. K, 0.82; E. D. B., 0.83; and for the three members 

 of the Laboratory staff, J. H. G., 0.79; E. L. F., 0.85; and H. M. S., 

 0.78. Using the results obtained with these eight subjects, covering 

 measurements on 3 to 71 days, and in most instances with three 

 periods each day, we may conclude that the average respiratory quo- 

 tient of a normal man in the standing position and the post-absorptive 

 condition is 0.82. This value is slightly lower than that found in 

 measurements made (usually on other days) with these subjects in the 

 lying position, both for the average value as well as in all but one of the 

 individual cases (see table 17, p. 91), and a little higher than the respi- 

 ratory quotient obtained at the Nutrition Laboratory with normal 

 men. 3 



HEAT-OUTPUT. 



The heat-output of these standing subjects, as calculated from the 

 calorific value of the oxygen consumed and the respiratory quotient, is 

 also given in tables 3 to 7, and represents the energy requirement of the . 

 subjects when standing quietly in the post-absorptive condition. This 

 value has been used as a base-line for calculating the increase in the 

 energy requirement due to the muscular effort of walking. 



The values of W. K. show considerable daily variation, but indicate 

 no regular change. With E. D. B. there is an apparent seasonal change 

 represented by the periods extending from October 4 to December 22, 

 1915, when the total heat-output per minute was 1.10 calories, and 

 from March 1 to April 15, 1916, when the average was 1.18 calories. 



J Zuntz and Schumburg, Physiologic des Marsches, Berlin, 1901, p. 259, also table 23, p. 258. 



2 Durig, Archiv f. d. ges. Physiol., 1906, 113, p. 263. 



Benedict, Miles, Roth, and Smith, Carnegie Inst. Wash. Pub. No. 280, 1919, p. 532. 



