Cakbon-Dioxide Elimination. 



167 



exercise on a bicycle ergometer which varied from moderate work to very severe 

 muscular work. In most of the experiments the carbon-dioxide production 

 of these individuals under the different conditions can be compared, and the 

 results are brought together in table 68. As an index of the amount of muscular 

 exercise, the heat equivalent of work done expressed in calories is given in the 

 footnote connected with the table. 



An examination of table 68 shows that there was a distinct tendency for 

 the carbon-dioxide production to be somewhat greater on the nights following 

 work periods than on the nights following days when the subject was at rest, 

 with the single exception of the experiments with J. F. S., in which there was 

 an average difference of but 0.1 gram. With the other subjects, however, the 

 tendency is marked, and particularly with the experiments where severe work 

 and very severe work were carried out. Of special interest is, perhaps, the 

 series of experiments with A. L. L. During 5 nights of rest after food, this 

 subject exhaled on an average 24.2 grams of carbon dioxide. The average for 

 11 nights after severe work was 26.7 grams, and one night, when the work 

 continued until 3 a. m., the carbon-dioxide production for the period from 

 4 a. m. to 7 a. m. was 28.4 grams per hour. 



Table 68. Carton dioxide eliminated during sleep (1 a. m. to 7 a. m.) 

 folloiving different conditions of activity. 



[Average per hour.] 



1 Heat equivalent of work done, 160 to 250 calories. 



2 Heat equivalent of work done, 130 to 280 calories. 



3 Heat equivalent of work done, 4S0 to 660 calories. 



4 Heat equivalent of work done, 420 calories. 



5 Heat equivalent of work done, 450 to 460 calories. 



Period 4 a. m. to 7 a. m. Heat equivalent of work done, 957 calories. 



In this last experiment, 1 the subject rode a bicycle ergometer at a high rate 

 of speed almost continuously from 8 a. m. until 3 h 01 m a. m. the next day, 

 at which time he stopped work, changed underclothes, and at 3 h 20 m a. m. he 

 was asleep. The carbon-dioxide production given in table 68 included the 

 period from 4 a. m. to 7 a. m., with due allowance for the carbon dioxide 

 residual in the chamber at the beginning and end of the period. Under these 

 conditions the carbon-dioxide production of this man was 28.4 grams, which 

 was very considerably higher than the carbon-dioxide production during sleep 

 following severe muscular work or during sleep following rest with food. 



1 Benedict and Milner, U. S. Dept. Agr., Office Expt. Stas. Bui. 175, p. 105, experi- 

 ment No. 64, 1907. 

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