For comparison with the values cited here, we have systolic blood pressures following walking which were obtained with a normal subject in the standing position in the course of another research some years ago. With this subject (a normal individual walking at the rate of 60 meters per minute for approximately 20 minutes) the general tendency for the systolic blood pressure was to show an increase of 5 to 8 mm. in the first observation after cessation of walking.

With the diastolic pressure for Squad A the immediate effect of work was usually to lower the pressure measurably, although Pec shows a rise of 16 mm. Practically all the other men show either a very slight rise or a pronounced fall. A lowering of 9 or more millimeters may be noted in the case of Gar, Gul, Pea, and Tom, the fall with Pea being 19 mm. The average diastolic pressures before work and the first quarter minute after work were 72 and 69 mm., respectively. The subsequent course of the diastolic blood pressure usually tended towards a slight rise, being in 9 cases higher at the end of 2 minutes than at the end of the first quarter minute. With Gar it rose from 62 to 76 mm. in 2.5 minutes and with Tom from 66 to 72 mm. With most subjects there was a tendency for the diastolic blood pressure to fall when the sitting position was assumed. At the end of 9 minutes after work, with the subject in the sitting position, the diastolic pressure was usually not far from that for the standing position prior to work, although some rather striking exceptions to this may be noted in the cases of Gul, Pea, and Pec. Especially worthy of note are the low values of 58, 56, and 54 mm. noted with Pea. These values are absolutely lower than any diastolic blood pressures heretofore noted with this subject, the lowest diastolic value shown in table 76 with this man being 60.

The immediate effect of work on the pulse pressure was in all but three instances a noticeable rise to an average pulse pressure of 35 mm. as compared with 29 mm. before work. The greatest rise was found with Pea, the pulse pressure changing from 18 to 40 mm., i. e., an increment of 22 mm. Kon, Pec, and Vea show falls of 6, 7, and 4 mm., respectively. The subsequent records indicate a definite tendency for the pulse pressure to fall as time passed. No great difference is noted when the subject changed to the sitting position. At the end of 9 minutes the pulse pressure is usually not far from that prior to work, except in the values found for Kon, Gul, and Pea.

Moderate Muscular Work And Blood Pressure. Squad B

Observations on systolic, diastolic, and pulse pressures were made with Squad B before and immediately after walking on the morning of January 28,1918. The data secured are recorded in table 79. A comparison of the values for the systolic pressure before walking with those obtained with the same subjects the evening before, (see table 77) is of interest. For the most part there is no great difference between the two series although certain of the men, particularly Kim and Sch, show very considerable increases over the evening record. The average for the systolic pressure for the evening of January 27 was 94 mm. and for the morning of January 28, 101 mm.

The effect of walking was determined, as before, by observing the blood pressures in the first 15 seconds after the cessation of walking.

Table 79. - Blood-Pressure Measurements Prior To And Immediately After 24 Minutes Of Level Walking On A Treadmill - Squad B, January 28, 1918

1 Ham, standing 3 min. after walking ended; systolic, 104 mm., diastolic, 80 mm., pulse pressure, 24 mm. 2 Wil, sitting. 6 min. after walking ended; systolic, 90 mm., diastolic, 64 mm., pulse pressure, 26 mm.; 10 min. after walking ended, systolic, 90 mm., diastolic, 66 mm., pulse pressure, 24 mm.

The systolic pressures for four of Squad B were somewhat lower in the first quarter minute than they were before work, but with the majority of the men they were perceptibly higher. The averages show, however, practically no change, being 101 mm. before, and 102 mm. for the first quarter minute after.1 It is to be noted, however, that whatever level the systolic blood pressure assumed after walking, it remained reasonably constant for at least 2 minutes with practically all of the men. As was found with Squad A no pronounced change in systolic pressure was noted with the men in Squad B when they assumed the sitting position.

The values for the diastolic pressures, when compared with those found the evening before, are almost always considerably higher, the most striking case being that of Ham, whose diastolic pressure the evening before was 55 mm. and in the morning prior to walking was 83 mm. The average diastolic pressure the evening before was 64 mm.; in the morning it was 78 mm. The immediate effect of walking was, in general, to lower appreciably the diastolic pressure at the end of the first quarter minute. This is in conformity with the findings noted with Squad A. Although with Squad A four cases of positive increment were found, with Squad B there were only two cases that did not show a measurable fall. The course of the diastolic pressure during the succeeding minutes tended almost uniformly to rise slightly. Thus, the diastolic pressure at the end of the second minute was in 8 instances higher than it was at the end of the first quarter minute, a phenomenon likewise observed in about the same degree in the case of Squad A. The increase between the first quarter minute and 2 or 2.5 minutes was 10 mm. in the case of Fis, 12 mm. with Sch, and 10 mm. with Liv and Sne. These increments are for the most part somewhat greater than those found with Squad A.

In comparing the pulse pressure of the men in Squad B, taken in the standing position before work on the morning of January 28, with that found the evening before with the men in the sitting position, we find that in general the pulse pressure was somewhat lower in the morning than it was in the evening, the evening average being 30 mm., and the morning average 23 mm. This difference is slightly greater than that observed with Squad A, i. e., 7 mm. as against 2 mm. for Squad A. Here again we find that the walking in practically every instance increased the pulse pressure, the one exception being that of Sch, his initial pulse pressure being 42 mm. and that in the first quarter minute after walking 30 mm. The subsequent course of the records following work shows a distinct tendency for the pulse pressure to become somewhat smaller as time went on, and at the end of 9 minutes with the subject in a sitting position the pulse pressure approximated that prior to walking. Three exceptions to this, however, should be noted. That is, with Sch the pulse pressure, which was 22 mm. at the second minute after walking, rose with sitting and at the end of 9 minutes was 36 mm. It will be remembered that Sch was the one man who showed a pronounced fall in pulse pressure after the walking. With Liv the sitting pulse pressure at the end of 9 minutes was considerably less than that found prior to walking, although the values for both systolic and diastolic pressures found with him prior to walking are open to some question on technical grounds. With Tho the pulse pressure of 12 mm. prior to walking is likewise open to suspicion; the level noted at the end of 9 minutes was 22 mm.

1 The increases of 3 mm. with Squad A and 1 mm. with Squad B are wholly incomparable with the normal rises recorded by Cotton, Rapport, and Lewis (Heart, 1917, 6, p. 269) of 15 to 45 mm., although both the kind and amount of work in the several cases are not strictly comparable.