424 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



The electrocardiograms taken to show the changes in heart rate due 

 to short periods of general muscular exertion fail to demonstrate any 

 pathological conditions, judged in the light of the available standards 

 with which we may compare such records. No subject ever com- 

 plained in connection with the test or asked to be excused or indicated 

 any fatigue following the exercise. The only consistent difference 

 exhibited between the men on reduced diet and those with uncon- 

 trolled diet is in the pulse-rate level, irrespective of whether we compare 

 periods of quiet when the subject is relaxed, periods of exertion when 

 the larger part of the voluntary musculature is under tension, or periods 

 of rest following such activity. The percentage of rise in the pulse- 

 rate occasioned by such activity, which is found on the average in the 

 20 pulse-cycles immediately following the activity, shows no significant 

 change with reduced diet, It therefore appears certain that the lower 

 nutritional level produced by continued low diet did not interfere with 

 the ability for adaptive increase in heart rate under conditions of 

 muscular exertion, when the needs of the organism naturally required 

 an increase in the circulation. Furthermore, it may be stated that no 

 annoying cardiac or respiratory symptoms, other than the described 

 normal changes, followed these periods of exertion. In all the records 

 there were no cases of extra systoles or skipped beats. 



TRANSITION PULSE. 



At the time of the treadmill experiments of January 28 and February 

 3, described on page 440, continuous electrocardiograms were taken 

 on each subject during 15 seconds of standing and the immediately 

 succeeding 60 seconds at the beginning of walking, and then again 

 during the last 15 seconds of walking and the following 30 seconds of 

 standing. The data thus obtained show the changes in duration of the 

 pulse cycles as the pulse-rate alters during the successive seconds of 

 walking or of standing. They also show how quickly the heart reacts 

 to the stimulus and at which cycle the pulse has reached its maximum 

 rate. We have termed these measurements the transition pulse as 

 they were taken during the time that the heart was adjusting itself to 

 the altered demands made upon it by the changed conditions of either 

 walking or standing. 



These measurements can best be presented graphically. Figures 

 95, 96, and 97 give the curves representing the transition pulse of the 

 individual members of Squad B on January 28, 1918, and figures 98, 

 99, and 100 show those for Squad A on February 3, 1918. Since the 

 measurements of the transition pulse were first made on January 28, 

 there are no basal data for any of these subjects, i. e., no data taken when 

 the men were Hving on a normal diet. To supply this lack of basal 

 material, five members of the Laboratory staff went through the 

 walking routine in the post-absorptive condition during the week of 



