AFTER-EFFECTS OF GRADE WALKING. 305 



lengthening of the duration of the cycle did not reach 0.2 second. The 

 duration of the pulse-cycle at the end of 2 minutes is thus less than 

 0.5 second, or, in terms of pulse-rate per minute, the change has been 

 from 176 to 125 beats. 



Curve D is composed of 5 records, covering a duration of 147 seconds, 

 and therefore is not continuous. Consequently, it must be considered 

 on a time basis rather than according to the number of consecutive 

 pulse-cycles. For the first 70 cycles the record was continuous and the 

 elapsed time was 30 seconds. In this time the duration lengthened to 

 about 0.41 second, or a total lengthening of 0.06 second. At the end 

 of 1 minute the duration fell another 0.01 second, and at the end of the 

 record, after 2 minutes and 27 seconds of standing, the duration of the 

 pulse-cycle was 0.49 second, or 0.14 second longer than at the transi- 

 tion. At the end of 1 minute or thereabouts, all four of these curves 

 begin to exhibit a marked irregularity in the duration of the pulse- 

 cycles, similar to that seen for the pulse during standing in figures 

 39, 40, and 41, with some suggestion of a rhythm in curves A and C, 

 recalling that seen in curve E in figure 41. 



From these curves it appears that the response to the change from 

 walking to standing is rapid, although slightly slower than with the 

 change from standing to walking; also, that the lengthening of the 

 pulse-cycle after walking had ceased continues at a uniform rate for 

 approximately a minute, during which time the rate decreases from 

 40 to 50 beats a minute. After the immediate drop in the first minute, 

 the change apparently becomes less marked, with wide fluctuations 

 in the cycle durations. 



AFTER-EFFECTS OF GRADE WALKING. 



As a part of the routine of the research, a few standing experiments 

 were made with E. D. B. following periods of grade walking, for a study 

 of the after-effects of the exercise on the standing metabolism. The 

 results are compared in table 86, in which the average pre-walking 

 values for the day are taken from table 6 and the grade-walking values 

 are drawn from table 16. In each case the length of the period of 

 walking, with the grade and the speed, also the length of period of rest 

 (sitting) between the walking and standing observations, are given in 

 table 86. As the values for December 21, 1915, to February 17, 1916, 

 inclusive, were obtained immediately after walking ceased, they 

 naturally represent rapidly changing values, especially in the ear i; > 

 part of the period. 



The experiments of February 26 to 29, inclusive, have three post- 

 walking periods each, with an interval of rest, i. e., sitting, of approxi- 

 mately 20 to 24 minutes before the measurements in the first standing 

 period began. The last period on each of these days was approximately 

 2 hours after walking. The changes in these last periods would 



