EXPERIMENTS WITH HORIZONTAL WALKING. 167 



from standing to walking, although the reverse was sometimes true. 

 The most striking point is the wide difference in the pulse-rate which 

 may be expected from the same subject, even when the conditions are 

 practically the same. It would appear as though the pulse is so sensi- 

 tive and variable, not only from day to day, but from minute to minute, 

 that any uniform figures are not to be expected, and even with the use 

 of experienced and well-trained subjects the conditions of the experi- 

 ments must be carried out with the least possible opportunity for 

 mental disturbance during the time of the experiment. 



In a recent study in the Nutrition Laboratory, 1 some pulse measure- 

 ments were made with a group of 12 normal young men, both while 

 they were standing and while they were walking on a level at a rate 

 of 70 meters per minute. The average standing value for this group 

 was 79 pulse-beats per minute, while for walking the average rate 

 varied from 88 to 85 beats between the first and twelfth minutes of 

 walking. The standing pulse-rates of W. K. and E. D. B. are thus 

 in keeping with this group average for standing, while the rates for 

 walking at this speed are somewhat lower. In the case of the group 

 of 12 men, it can not be said that the subjects were particularly 

 trained for these experiments, though they were physically active and 

 athletic young men. 



Benedict and Murschhauser 2 report that on two days their subject 

 showed a lower pulse-rate during level walking than in the standing 

 portion of the experiment, in spite of the fact that the metabolism was 

 increased over 100 per cent above the basal requirements. This 

 observation was so contrary to the general relation between the pulse- 

 rate and the metabolism that further tests were made at the Nutrition 

 Laboratory and similar results found. In later work 3 with a group 

 of 5 normal men this observation was not confirmed. 



In a careful study of the records of W. K. and E. D. B. in the present 

 research and the exclusion of all cases in which there might appear to 

 be some disturbing influence which produced an unduly high pulse-rate 

 for the standing position, we have found the instances given in table 46 

 of pulse-rates that are lower during level walking at moderate speed 

 than during the preceding time when the subject was standing. Thus, 

 W. K., during the standing period on March 16, in three counts from 

 9 h 7 m a. m. to 9 b 19 m a. m., had a pulse-rate ranging from 77.7 to 

 84.1 beats. The subject began walking at 10 b 45 m a. m. at a speed of 

 59 meters per minute. After he had walked 14 minutes, his pulse-rate 

 was 72.7 and later 74.5. In this particular instance, the records for 

 standing were obtained in the first period of the experiment, while those 

 for walking were for the fourth period on that day; for the intervening 



Benedict, Miles, Roth, and Smith, Carnegie Inst. Wash. Pub. No. 280, 1919, p. 442. 

 ^Benedict and Murschhauser, Carnegie Inst. Wash. Pub. No. 231, 1915, pp. 54, 55, and 85. 

 'Benedict, Miles, Roth, and Smith, Carnegie Inst. Wash. Pub. No. 280, 1919, p. 451. 



