Variations in Metabolism. 243 



comparison of metabolism while sitting with metabolism 



while standing. 



When the subject is quietly seated in a chair, the metabolism is invariably 

 somewhat higher than when he is lying on a bed asleep. If a subject is trained 

 to so regulate the muscular tension by his will as to reduce it to the minimum, 

 the differences in the carbon-dioxide excretion during such muscular relaxation 

 when lying down awake and when asleep are not measurable. On the other 

 hand, sitting up calls for a different readjustment of the muscular system with 

 variations in the tonus and the sitting posture does not permit of as complete a 

 relaxation of muscular tension as does lying down. Standing requires a still 

 further readjustment of muscular tension and the variations in metabolism 

 between sitting and standing are of unusual interest. Many individuals stand 

 the greater part of the day while at work, at a bookkeeper's desk, for instance, 

 or at other occupations which do not demand strenuous muscular exercise, but 

 do require a standing position. In order to throw some light upon the varia- 

 tions in metabolism when standing as compared with sitting, 5 experiments 

 were made in which the subjects sat for 2 to 1 hours and immediately after- 

 wards stood for 2 to 3 hours. During the two periods the four factors of the 

 grosser metabolism were measured. The results have been gathered in table 102. 



As might have been expected, there is an increase in practically all the experi- 

 ments during the standing period, although singularly enough with the subject 

 H. E. D., there was a lowered carbon-dioxide exhalation, and water vaporiza- 

 tion, and a decreased oxygen absorption. On the other hand, there was a notice- 

 able increase in the heat production. Likewise, in the first experiment with 

 A. H. M. there was a slight decrease in the heat production when standing. 

 These discrepancies serve to show admirably the difficulties attending experi- 

 mentation in short periods, and the individual experiments and the individual 

 periods must be looked upon as giving only tentative results. On the other 

 hand, the average of 5 experiments can be considered a reasonably accurate 

 index of the normal condition. As an average of the 5 experiments we find 

 that there is an increase of carbon-dioxide elimination amounting to 3.1 grams, 

 of water vaporized 2.2 grams, of oxygen absorbed 3.4 grams, and of heat pro- 

 duced 12.9 calories per hour. These values correspond to an increase in the 

 carbon dioxide of 12.4 per cent, of water 6.9 per cent, of oxygen 15.2 per cent, 

 and of heat 16.5 per cent. There is, then, on the average, an increase of about 

 15 per cent in the metabolism when a person stands over the metabolism when 

 sitting. 



This comparison brings into discussion the interesting relations between 

 external muscular work and static work, a problem that has received much 

 attention from Johansson 1 and his co-workers. The play of muscles required 

 to hold the body in an upright position may be considered as very small and 

 obviously the nicety with which the body is balanced, the less the work required 



1 Johansson, Skand. Archiv f. Physiol. 1901. 11, p. 273. 



