PULSE-RATE. 



417 



until the exact moment when he was to grasp the bar and "chin" him- 

 self, the beginning of which event is represented by the vertical heavy 

 line. Immediately at the beginning of exercise the cycle length is 

 shortened and continues to decrease during the 5 seconds of muscular 

 tension, the end of which is indicated in each curve by a short vertical 

 line. 



The curve for December 9 in figure 92 is at a higher level — i. e., a 

 faster pu se-rate — particularly in the period of quiet and of rest. It is 

 also to be observed in the case of this curve that at the end of the exer- 

 tion the pulse continues to rise during about 5 cycles, after which it shows 



Fig. 92. — Changes in the pulse-cycle duration with exertion, Kirk G. Montague. 



The portion of the curves to the left of the heavy vertical line represents the pulse cycles during 

 quiet. Between the heavy vertical line and the short lines through the curves is the period 

 of exertion. The portion at the right of the short verticals is for the period of recuperation. 



a steep decline. December 9 was not long after the Thanksgiving vaca- 

 tion, and the pulse-rate had risen on this date to more nearly its normal 

 level. On November 11 and January 27 the reduced diet had been in 

 force for several weeks continuously in each case and the pulse was at a 

 lower level. The difference in level between December 9 and the other 

 two dates is particularly prominent in the quiet pulse, that is, preceding 

 the activity. It is less prominent in the rest pulse following the 

 activity and rather slight during the activity. It is significant that the 

 cycle length during exercise is so nearly the same, even though the 

 resting pulse is at rather widely different levels. It would appear that 



