By referring to the normal transition curves shown in figure 101,1 the average pulse-rate for the first 60 seconds of walking may be very closely determined; these averages are as follows: T.M.C, 98; E.L.F., 90; H.W.F., 81; H.M.S, 80; and H.S., 91. From table 101 it is seen that the pulse-rates as determined by counting the beats during the first third of the second minute, i. e., "after 1 minute of walking" as stated in the table, are T.M.C, 88; E.L.F., 87; H.W.F., 80; H.M.S., 80; and H.S., 90. This shows a drop between the average pulse-rate for the first 60 seconds and that of the first part of the second minute of 10 beats for T.M.C, 3 beats for E.L.F., 1 beat for H.W.F., 0 for H.M.S., and 1 beat for H.S. and, in connection with the curves for the first minute shown in figure 101, indicates that the heart action quickly reached its maximum and began to moderate during the first minute, continuing the falling rate into the third and fourth minutes as previously pointed out. A further inspection of the curves in figure 101 shows that this slowing of the rate begins probably within 20 seconds after the walking starts, or in other words, that the pulse overshoots at first the rate needed for the exercise to be performed, and after the first 20 seconds begins an adjustment from the higher rate of stimulus to the lower rate of requirement.

1 See page 436.

In an earlier publication1 it was stated that a lowering of the pulse-rate was noted with several subjects on the change from standing to walking. These results are not confirmed by the figures of table 101. The fact that the rates during the 15 seconds of standing preliminary to walking, as found from figure 101, are higher than the standing average for the 10 minutes given in table 101, and that the rates of T. M. C, H. W. F., and H. S., after walking 6 minutes (see fig. 101), have fallen to approximately the preliminary standing rates suggests that possibly the earlier observations were unwittingly taken at the points of highest and lowest changes during this transition period. It is evident that these changes have not yet been sufficiently studied and that measurements of the pulse cycles over longer periods than has been done in this study and the elimination, if possible, of the psychical effect incident to the starting of the treadmill must be made.

Table 102 summarizes the walking pulse data presented in the preceding tables, and shows the average pulse-rates for the sitting, standing, and walking observations, the increase in the number of beats, and the percentage deviation from the average preliminary standing pulse of each group. It is seen from this table that for the two normal groups the change in the number of beats per minute on passing from sitting to standing is 8 for the 5 normals and 7 for Squad B normal, and on passing from standing to walking, both groups had an increase of 9 beats. This is a change of 12 per cent in each instance for the 5 normals and of 10 and 11 per cent for Squad B normal. For the two diet squads, the change in the number of beats on passing from sitting to standing is about the same as for the normal groups, but on account of the normally low initial pulse-rate of the diet squads, the percentage changes are slightly higher. During the walking period the increase in the pulse beats per minute is approximately twice as great for Squad B 20-day as for Squad B normal, with increase in an accompanying percentage change. Squad A 120-day does not show as great changes as does Squad B 20-day, but is higher than the normals both in absolute change in number of beats as well as percentage change. The pulse-rate for standing 2 minutes after walking and the final sitting rate do not indicate that any one group had a greater tendency to a delayed return to the normal rate than another. In fact, Squad A after 120 days of low diet and the five normals were both at the average preliminary sitting rate after 8 minutes, while Squad B normal and Squad B 20-day vary from 5 beats below to 1 beat above the preliminary sitting rate.

1Benedict and Murschhauser, Carnegie Inst. Wash.

Table 102. - Comparison Of The Average Pulse-Rates Of A Group Of 5 Normal Men And Squad B Normal With Squad B 20-Day And Squad A 120-Day Diet, While Sitting, Standing And Walking, And Standing And Sitting After Walking

1At 8 minutes.

2At 7 minutes.

3Average of 8-9 minutes.

From the data given in tables 138, 140, and 142, the percentage change in the metabolism between standing and walking as shown by the heat output may be computed. This corresponds to 215 per cent for Squad B normal, 239 per cent for Squad B 20-day diet, and 215 per cent for Squad A 120-day diet, or the increase in the metabolism with walking 70 meters per minute as compared with the metabolism with standing is approximately alike for the normal and diet squads at about 220 per cent. In contrast with this large percentage increase in the metabolism it is seen from table 102 that the pulse-rate increases more nearly 25 per cent for the diet squads and 10 per cent for the normal squads. This contrast between the percentage changes in the pulse-rate and the metabolism which has been noted before in connection with a series of walking experiments and which differ from those found during muscular work on an ergometer1, will be discussed in connection with another series of observations in this laboratory the results of which are being prepared for publication.

1Benedict and Murtchhauser, Carnegie Inst. Wash. Pub. No. 231, 1915, p. 85.

In conclusion, as regards the effect of moderate walking upon the pulse-rate of men subsisting on a restricted diet, it may be said that the same relatively low pulse-rate was present during walking as during sitting. Second, the increases of the standing over the sitting pulse-rate were in absolute number of beats and on a percentage basis slightly greater for the diet squads than for the normal groups. Third, the pulse reached a settled rate as quickly and maintained it as uniformly with the diet squads as with the normal groups. Fourth, the return to the rate preceding walking was irregular and does not admit of a statement that one group showed any marked difference from the others.