92 BENEDICT AND JOHNSON— ENERGY LOSS OF 



give practical living conditions, they were determined two hours 

 after a very light breakfast and with the degree of repose possible 

 with the subjects sitting quietly, reading. Hence, this standard 

 value or base line should not be confused with true basal minimum 

 metabolism measurements. From past experience, the standard 

 value here used may be estimated to be not far from lo per cent, 

 higher than the true basal or minimum value. 



All of our experiments were made with one or more periods at 

 the beginning, in which the standard value was established for the 

 day under the conditions outlined. Observations were then made 

 of the increment due to reading aloud, singing, sewing, standing 

 quietly, sweeping, dusting, standing up and immediately sitting down, 

 and with the subjects marching in single file around the chamber. 

 These observations are now being extended so as to include many 

 more household activities. The ages, heights, and body-weights of 

 all of the subjects have been recorded. The calculations of the 

 metabolism have been made on the basis of uniform body-weight, as 

 Harris- has recently shown that the metabolism per kilogram of 

 body-weight is, with homogeneous material, a satisfactory method 

 of comparison. 



Since every experiment contained periods in which the standard 

 metabolism was determined for use as a basal value, a considerable 

 amount of data is available showing the metabolism of the subjects 

 while they were sitting quietly, reading. The results of these quiet 

 periods are given in Table I. as heat output per kilogram of body- 

 weight per hour. In computing these values, we have assumed a 

 respiratory quotient of 0.90, since all of the experiments were made 

 two hours after a light breakfast. The calorific value of carbon 

 dioxide at this respiratory quotient has therefore been used in all of 

 our calculations, namely, 2.785 calories per gram of carbon dioxide. 

 From this series of experiments on twelve different days, embody- 

 ing twenty-three periods, in which over two hundred women i)ar- 

 ticipated, it is seen that the average heat production per kilogram 

 per hour was 1.12 calories. This average figure of 1.12 calories has 

 a specific interest in that it indicates the probable heat production of 



2 Harris and Benedict, Carnegie Inst. Wash. Pub. No. 279, 1919, p. 160. 



