Daily Basal Pulse-Rate With Lying Position. Squad A

The pulse-rates secured with the subject lying in the post-absorptive condition - i. e., the conditions obtaining during the measurement of basal metabolism - should first be considered. For these we have very complete records for Squad A extending throughout the entire period of observation, namely, from September 27 to February 3, inclusive. These records were secured under uniform conditions and for the most part in Sprinefield, but a few were made in Boston. The daily averages are expressed in table 80 as pulse-rates per minute. The pulse-rates prior to the morning of October 5 were obtained with the subjects on normal diet. The pulse-rates for subsequent days were recorded during the period with the reduced diet. Comparing the rates prevailing at the beginning of the experiment with normal diet and those at the end of January with reduced diet, we find a pronounced fall in pulse-rate in every instance. This striking reduction in pulse-rate is so great with most of the subjects that frequent observations are recorded of pulse-rates between 35 and 40 per minute and even lower. To lay particular emphasis upon the low rates, all values between 40 and 36 inclusive are printed in italics, and the values of 35 or below in bold-face type. An inspection of the table shows the incidence of the italicized figures as the study progressed. The members of the squad with whom italicized figures occur increase in number with the length of the period of reduced diet until, in the last week in November, 8 of the squad show values of 40 or below. As a matter of fact this represents the minimum pulse for the squad as a whole. At the end of the experiment, 5 men show values of 40 or below, but the number of low counts is somewhat less than those which appear in the table in the latter part of November.

Table 80. - Daily Pulse-Rate1 Of Squad A

[Subjects In Lying Position, Without Food.]

1 These observations were made early in the morning at least 12 hours after the last meal and for the most part are averages of a considerable number of pulse-rates taken during the two periods on the respiration apparatus.

2 These records were obtained with Fre who left Squad A on Oct. 25.

3 Day following this date was an uncontrolled Sunday; no record taken.

4 Kon was on normal diet on this day, and hence this pulse-rate is not included in the average.

5 Spe on Oct. 27 believed he had a touch of grippe; this pulse-rate not included in the average.

1These observations were made early in the morning at least 12 hours after the last meal and for the most part are averages of a considerable number of pulse-rates taken during the two periods on the respiration apparatus.

2 Records on this date taken in Boston in the group respiration chamber.

3 Thanksgiving recess, Nov. 29 to Dee. 2 inclusive.

4 Christmas recess, Dee. 20 to Jan. 6, inclusive.

1 These observations were made early in the morning at least 12 hours after the last meal and for the most part are averages of a considerable number of pulse-rates taken during the two periods on the respiration apparatus.

2 Records on this date taken in Boston in the group respiration chamber.

3 Note that for these subjects the maximum occurs in January; with the others it appears early in the series.

Special emphasis should be laid upon the appearance of the boldface figures indicating 35 counts or below. These are found with 5 subjects during the month of November and in the latter part of January. Records of 32 or below appear in 4 cases in November and the absolute minimum was clearly and definitely established with Vea on November 19 of 29 beats, this record being the average of a series of 6 counts. The actual counts for this particular subject on November 19 were: 30, 29, 29, 28, 29, and 30. Thus we have four separate counts of 29 or 28. After several months' personal practice in counting his own pulse-rate, in which he had been frequently checked by one of our observers, this subject made a report that on January 31 he counted his pulse while sitting in the class room at 10h15m a. m. and found it to be 32 per minute; later at llh30m a. m., after lying down about 4 minutes in his room, he found the pulse-rate as counted by himself to be 28 beats per minute. It thus seems definitely established that we have with this subject a clear case of a pulse-rate which on two occasions was below 30 beats per minute.

The fluctuations in pulse due to the novelty of the situation and slight psychological disturbances are perhaps best shown in the 7 days prior to the reduction in diet. In a sense, the average of these days may be considered as the average resting pulse of these men prior to dietetic restriction. In the majority of. cases such an average would be legitimate, but in the case of Vea the pulse-rate on the first three days is obviously higher than on the last three days of the normal diet period. The period of the lowest pulse-rate with the squad as a whole occurred in the week between November 17 and November 25, inclusive. The average pulse-rate of these men prior to the reduction in diet may profitably be compared with the average for this week to determine the maximum average change in pulse-rate. This is done in table 81.

Table 81. - Comparison Of Pulse-Rate During Normal Diet With The Lowest Level Of Pulse-Rate During Reduced Diet1 - Squad A

(Weekly averages). [Subjects in lying position, without food].

1 See table 80 for the material from which these data have been drawn.

Using as a basis of comparison the average pulse-rate from September 27 to October 4, when the subjects were on normal diet, we find in all cases a fall in pulse-rate due to the diet, although the differences, of course, are not so large as the differences between the maximum and minimum noted in table 80. The smallest drop was with Bro (5 beats) and the maximum with Moy and Tom (21 beats). On the average the pulse-rate was lowered 14 beats or 25 per cent.

It is thus seen that the general picture of a marked fall in pulse-rate is indicated in every case; the only variations are in the degree of the fall. A comparison between the maximum normal pulse and the minimum pulse found on any day of reduced diet would indicate the maximum variations for the subjects.

When it is remembered that the pulse-rates recorded in table 80 are the average of not less than 3 and for the most part 6 or more counts, it is seen that we deal here not with isolated 1-minute counts, but with a true representation of the pulse level for that particular day. That fluctuations occurred from time to time from uncontrollable causes, even during the morning, was frequently noted by some of our observers. Such illustrations were sometimes recorded by one of the student observers, Mr. Charles Wesley Davis, who assisted in the pulse counts at Springfield. From his thesis prepared in connection with his college work, we have selected for record here the following instances of somewhat rapid changes in pulse-rate during the morning experiments.

On October 24, while Pec was resting on the cot during the morning experiment, a sudden nervous impulse caused him to kick his leg. As a result, his pulse-rate jumped from 42 to 52 for a minute. When Kon first came on the squad for experimentation, Dr. Roth spoke to him about keeping awake. His pulse, which had been 44, immediately went to 58. Gul had a habit of taking occasional deep yawns during his morning tests. His pulse always went up after such a yawn, his average rise being from 6 to 10. Mon and Tom were examples of men whose pulse fluctuated at intervals for no apparent reason. Upon questioning the men, it was often found that they had been thinking of something exciting. A striking example of the psychical effect upon the pulse was noted with Gar on November 14. His pulse-rate rose from 36 to 50, yet he remained perfectly quiet. He admitted later he had been thinking about an examination that was due on the same morning and was doubtful about his knowledge of the subject. Mon's pulse showed sudden and wide variations from slight changes in body position. When he first lay down on the cot January 30, his pulse was 56 per minute. Eleven minutes later he was asleep with a pulse-rate of 46. After he changed to another cot and the mask was attached for the respiration experiment, his pulse went to 54.