460 VITALITY AND EFFICIENCY "WITH RESTRICTED DIET. 



this day the longest time required for return to normal was shown by 

 Mon (11 minutes) and Moy (12 minutes). With the resumption of 

 full diet, the time for return to normal increased, being on the average, 

 11.2 minutes on February 8, 11.8 minutes on February 11, 7.7 minutes 

 on February 15, and 7.5 minutes on February 18. Although the num- 

 ber of men included in the average is not always the same, the figures 

 give a clear indication not only that the time lengthened when the men 

 returned to full diet, but that on the later days in February there was 

 a tendency with most of the subjects for the pulse-rate to return to 

 normal a little more rapidly than during the first days of full diet. 



An interpretation of the true effects of the low diet upon the return 

 of the pulse to normal after work is, from the data with Squad A (table 

 105), extremely difficult. At the period in November and December, 

 when the body-weight was approaching a minimum and the caloric 

 intake was very low, we find some of the highest figures, that is, the 

 longest delayed return to normal. After the return of the men from 

 the Christmas vacation, i. e., during the month of January, the squad 

 as a whole reached a level very considerably lower. The average 

 values for January are, however, vitiated by the fact that both Spe and 

 Tom were not in the squad and the pulse-rate with both of these men 

 had previously required a long time to return to normal level. The 

 figures for this month are distinctly at variance with those for Novem- 

 ber and December, and but few direct conclusions can be drawn. 

 The possibility of a training should not be lost sight of. In the 

 absence of clear-cut evidence we can only consider the difference 

 between the return to normal of the pulse-rate during the month of 

 January and that found subsequently after the resumption of feeding. 

 Here the picture is very clear, namely, an increased lengthening of the 

 time required in the latter period, but the situation is also complicated 

 greatly by the ingestion of a large amount of food with pronounced 

 katabolic processes, involving the deposition of fat and a general 

 increase in weight. Unfortunately, as will be subsequently seen, 

 reference to the data obtained with Squad B does not materially 

 clarify the situation. 



The correlation between the rapidity of return to normal of the 

 heart rate and the physical condition of man has been especially studied 

 by Pembrey and' his associates.^ His general conclusion is that with 

 the untrained man the return to normal is longer than with the well- 

 trained man. *'The pulse of the trained man has a slower rate at rest, 

 a wider range in response to muscular work and a more rapid recovery 

 after exercise." 



The picture for Pea and Pec and the delayed return with the entirely 

 untrained man Tom are in full conformity with Pembrey's views, but 



* Pembrey and Todd, Journ. Physiol., 1908, 37, Proc. Physiol. Soc, Oct. 17, p. Ixvi. Pembrey'a 

 work is best summed up in his article with Cook, Journ. Physiol., 1913, 45, p. 446. 



