The figures given for the sixth, twelfth, and twenty-fourth minutes were counted from the photographs, while the other pulse-rates were counted visually from the deflections of the galvanometer string. Failures to secure records for Lon and Tho for the walking periods were due to illegible records on account of defective grounding of the subjects. Other missing records are due to various causes. It has been necessary, therefore, to take for the averages such data as were available.

All of the subjects had a low pulse-rate, regardless of whether they were sitting, standing, or walking. The average for the sitting pulse for the 7 subjects whose records are available is 46 beats, the figures for the individ ual subjects all being lower than those for the sitting pulse taken the evening previous and given in table 87. After sitting for 10 minutes the subjects stood and the records were taken as a rule after 1 minute and 10 minutes of standing, with as many intermediate records as opportunity permitted. In each instance there was an increase in pulse ranging from 3 beats or 8 per cent for Liv to 21 beats or 41 per cent for Sne, with an average pulse-rate of 55 for the 9 subjects, an increase of 9 beats or 20 per cent. The average pulse-rate with the subject standing in the chamber is slightly lower than the pulse taken outside the chamber, but the changes are both positive and negative. These pulse-rates were counted at different intervals of standing and there is not the uniformity in this respect that there was with the other pulse-rates taken for standing. The records as a whole may be said to show that the subjects had adapted themselves to the conditions and that there was nothing abnormal about any of the pulse-rates. The records for those counted at the end of 1 minute of walking all show an increase above the standing pulse inside the chamber, varying from 8 beats or 13 per cent for Kim to 19 beats or 41 per cent for Wil. The average pulse-rate for the group had increased 17 beats to a rate of 69 or an increase of 33 per cent. The same fall in pulse-rate between the end of 1 minute and the end of 6 minutes is noted here as was observed on January 6, Wil being the only exception to this general behavior.

Table 99. - Pulse-Rate Per Minute Preceding, During, And Following Walking In The Treadmill Chamber With Percentage Change From Rate Standing In Chamber Before Walking - Squad B, January 28, 1918

1Rate at 7 minutes.

2Based on rate standing outside chamber.

3Rate at 10 minutes.

4Rate at 5 minutes.

The fact that there was a drop in the pulse from the first minute is evident in a study of the rates shown for the intervening minutes. It is seen that the heart had begun to recover from its first stimulus of walking at the end of 2 minutes, for there was a drop in every instance, except for Kim, whose rate remained the same but fell off by the end of 3 minutes of walking, and for Wil, whose pulse first showed a drop at the fifth minute. Eight of the 10 sets available for comparison show that the fall following 1 minute of walking reached its lowest point by the end of the third or fourth minute. By the end of 6 minutes, in 5 out of 7 cases the rate had increased from this low point, though it had not reached the rate of the first minute. By the end of 12 minutes Wil had a pulse faster than at the end of 1 minute, while the others were about at the 1-minute rate or slightly below. Unfortunately, there are only 6 records reported for the twenty-fourth minute, but if the count for either the twenty-third or twenty-fifth minute is used in place of that lacking for the twenty-fourth minute, it is seen that Har, Sch, and Sne still had lower pulse-rates than after 1 minute of walking, while Liv had the same. The other subjects had pulse-rates slightly in excess of that following 1 minute of walking. This relationship was likewise found on January 6 (table 98), viz., that 1 minute of walking was sufficient to bring the pulse to a rate that 24 minutes of walking did not materially change.

During the 2 minutes which immediately followed walking, the subjects were standing on the treadmill while the blood pressures were being measured. It is obviously impossible to compare the pulse-rates under these conditions. It may be said, however, that for the 7 cases where the rates are given at both 30 and 120 seconds, the average at 30 seconds is 9 beats below the average for the same seven subjects at their last walking rate, and that the rate at 30 seconds is already at a level which is unchanged by standing 120 seconds. Two minutes of sitting, which was a total of 4 minutes after the walking ceased, was sufficient to bring the pulse down to the original sitting rate.

The pulse records for Squad A in the walking test of February 3 appear in table 100. The details of this test were carried out in the same manner as those for the experiment on January 28. The sitting and standing pulses were the averages of 2 to 5 counts, except for Moy and Pea while sitting, and Gar, Moy, and Pea while standing in the chamber, when only 1 count was made. The sitting pulse of Tom was relatively high as compared with that for other members of the squad, but this is in keeping with his sitting pulse for the evening previous as shown in table 86.

The average sitting pulse for the 11 members of the squad was 52. With the subject standing outside the chamber, the pulse-rate was greater in every instance except for Gar, with whom there was a drop of 2 beats. The sitting pulse in his case is the average of counts taken after 2, 3, 8, and 9 minutes and the standing pulse was counted after 1,3, and 5 minutes of standing. This seems a very definite case of not only an absence of increased rate for standing over that for sitting but an actual, though small, drop in the pulse-rate. In the 8 observations available for comparison the average pulse-rate rose 11 beats with standing to a rate of 63 or 21 per cent above the sitting rate. The rate with the subject standing on the treadmill varies somewhat from the rate when he was standing outside the chamber, as was the case with Squad B on January 28. In 4 cases there was an increase, but the average fell to 60, a change similar to that observed for Squad B on January 28.