958 



NUTRITION AND HEAT REGULATION. 



containing the above number of calories in twenty-four hours 

 should cover the needs of the resting body, but under ordinary 

 conditions the body does not remain at rest. There is always a 

 greater or less amount of muscular activity, which means an 

 increased metaboHsm, and which requires, therefore, a correspond- 

 ing increase in the daily diet. Thus, during the late war, the 

 Interallied Food Commission established a dietary of 3300 calories 

 for men doing an average amount of muscular work for eight 

 hours a day, about twice the estimated basal metabolism. 



YRS. 10 



40 



50 



Fig. 301b.— Du Bois's figure to show the variation of basal metabolism with age. The 

 results are expressed in terms of calories per square meter of body surface per hour; the age is 

 given along the abscissa and the calories per square meter per hour along the ordinates.— (From 

 E.F. Du Bois, "American Journal of the Med. Sciences," June, 1916.) 



Basal metabolism is expressed not only in terms of the body 

 weight but also and perhaps more frequently in terms of the 

 body surface, on the belief that the extent or area of this surface 

 is a determining factor in the heat loss. Expressed in this way 

 it is found that the basal metabolism of the adult is approximately 

 40 calories per hour per square meter of skin surface. Basal 

 metabolism furnishes a means of comparing the fundamental rate 

 of metabolism under different conditions in health and disease, 

 independently of the effect due to muscular work and other in- 

 cidental circumstances. The suiiace area of an individual may be 

 estimated conveniently from the weight and height by means of a 

 formula devised by E. F. and D. Du Bois:* 



A = W0.425 X H0.725 X 71.84 



Making use of this formula, whose average error is about 1.7 per 

 cent., these authors find that in adult Hfe the basal metabohsm 

 of different individuals shows a quite constant relationship to the 



* Du Bois, D. and E. F. 

 and 17, 863, 1916. 



'Archives of Internal Medicine," 15, 868, 1915, 



