536 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



humidity for the experiments on January 6 with Squad B was not 

 far from 33 per cent and on January 28 approximately 30 per cent; 

 on February 3, with Squad A, it was perceptibly higher, and more 

 nearly 50 per cent. 



Obviously in experiments lasting but 20 to 24 minutes, barometric 

 changes are physiologically insignificant. 



The more important data from the experiments on January 6 with 

 Squad B have been brought together in table 138. It is specially to 

 be noted that the body-weight used in all of these treadmill experi- 

 ments is not that appearing in all other tables of this monograph, but 

 includes the weight with clothing, electrodes, and pneumograph, for 

 we are particularly interested here in the actual weight transported 

 in the process of walking. These men had their last meal at 5 p. m. 

 the evening previous, so Van, who was the first subject, had been 12 

 hours without food and was therefore in the post-absorptive condi- 

 tion. This subject was wakened at 4 a. m. and began his standing 

 experiment at 4^25™ a. m. ; as the squad had retired at 11 p. m., he had 

 had only 5 hours of sleep that night; but Tho's walking experiment was 

 not made until 12*^25™ noon; it was therefore 19 J hours since his last 

 meal, but he had had a full night's rest. These differences in the 

 hours of rest and intervening time between the previous meal and the 

 experiment could not be avoided in these individual measurements; 

 though undesirable, they were probably without significant influence. 



From table 138 it is seen that the rate of walking is practically 

 uniform at 69.4 meters per minute, even the grossest variation being 

 only 0.5 meter. This is evidence of the careful control of the treadmill 

 speed. The total heat per minute is recorded in column h. As was 

 the case with the standing metabolism, the total heat output is in 

 general agreement with the weight of the subject, the heaviest men 

 having usually the largest heat output. The exceptions to this were 

 no more frequent nor larger than might be expected in general. 

 Although the speed of the treadmill was adjusted to that for moderate 

 walking, it seems best to discuss the total distance walked more in 

 terms of an average day's walking performance for these men. It 

 was found that, in general. Squad A showed pedometer records of not far 

 from 6.5 miles per day.^ Consequently we have used for both squads 

 the round figure of 10 km. to represent the total distance walked daily. 

 The total heat required in walking 10 km. has been computed for Squad 

 B and recorded in the last column of table 138 (column I). The aver- 

 age value of 626 calories as the heat produced while walking 10 km. 

 corresponds approximately to one-seventh of the daily net energy 

 intake of the men in Squad B at this time. The value for the average 

 heat required to walk 10 km. (626 calories) may be assumed to be a 

 basal unit which will be referred to when the experiments made upon 

 the subjects at the lower nutritional level are considered. 



1 See p. 645. 



