PHYSIOLOGY: H. M. SMITH 
159 
ber under normal conditions was alike, a comparison of the three sets of 
experiments may fairly be made. This shows a drop in the energy expended 
per man per kilometer of 8.7 calories for the twenty-day diet and of 13.8 
calories for the four months' diet. 
That this drop in the energy requirement is not wholly due to the fact 
that there was less body weight to be moved may be seen by considering the 
heat requirements from the second viewpoint, viz., on the basis of a kilogram 
of body weight transported one horizontal meter. 
In considering the energy requirements on this basis, it is usual to deduct 
from the total heat measured that portion which may be ascribed to the 
basal requirements of the body in a position of rest. Therefore, in addition 
to the series of walking experiments just described there was also conducted a 
series of experiments while the subjects were standing quietly. These were 
carried out with a portable respiration apparatus in an adjoining room imme- 
diately preceding the walking experiment. The difference between the stand- 
ing and walking metabolisms may then be attributed to the superimposed 
TABLE 2 
Reduced Diet and Heat Required per Kilogram of Body Weight in Walking 1 
Horizontal Meter 
SQUAD 
CONDITION 
HEAT PER 
HORIZONTAL 
KILOGR AMMETER 
GAIN OVER NORMAL 
g.—cal. 
per cent 
Normal 
0.610 
Control ... 
20-day diet 
0.561 
8 
Diet 
4-month diet 
0.522 
14 
requirement due to walking, and from the distance walked in unit time and the 
body weight, the requirement per horizontal kilogrammeter may be obtained. 
The three sets of experiments figured upon this basis are given in table 2. 
Here is shown a decreasing energy requirement from 0.610 gram calorie per 
horizontal kilogrammeter for the control squad in normal condition to 0.522 
gram calorie for the diet squad after subsisting four months on a diet of about 
two-thirds normal. This reduction in the energy from 0.610 to 0.522 gram 
calorie per horizontal kilogrammeter amounts to an increase in efficiency of 
approximately 14%. 
The results of these experiments are quite positive and show a marked sav- 
ing in the energy requirements for walking in favor of the reduced diet whether 
considered on the basis of the gross energy expended which represents the 
real cost to the individual and to the national food reservoirs, or on the basis 
of the energy required per horizontal kilogrammeter. Although the results 
here submitted are confined to one form of muscular activity nevertheless 
it is believed that the quantitative results obtained would be duplicated if 
other forms of muscular work were studied. 
