144 CONDITIONS INFLUENCING THE FREQUENCY OF THE PULSE. 



CONDITIONS ^INFLUENCING THE FREQUENCY OF THE PULSE. 



In the normal adult male the number of pulse-beats is 71 or 72 in the minute, 

 in the female about 80. Other factors that influence the frequency are : 



(a) Age: 



Beats in the Beats in the 



Minute. Minute. 



New-born 130140 ioth-1 5th year 78 



1 year 120130 i5th-2oth . 70 



2 years 105 2oth-25th 70 



3 100 25th~5oth 70 



4 97 6oth year 74 



5 94 90 8oth year 70 



10 years about 90 8oth~9oth year over 80 



(b) The length of the body stands in a definite relation to the frequency of 

 the pulse. Volkmann gives the formula p l == j^~ 1 in which P and P! represent 

 the pulse-frequency and L and L 1 the body-length. Rameaux suggests the 

 following formula: N x = Nj/j^' f in which N and N\ represent the ptilse-fre- 

 quency and D and D x the body-length. By means of this formula the pulse- 

 frequency has been calculated from the body-length in a number of healthy 

 individuals with the following results: 



Length of the Body Pulse: 



in Units of 10 Cm. Estimated Observed. 



80-90 90 103 



90100 86 91 



IOO HO 8l 87 



no 120 78 84 



120-130 75 78 



130-140 72 76 



140-150 69 74 



150160 67 68 



160170 65 65 



170180 63 64 



Over 180 60 60 



As it is possible to determine the pulse-frequency from the body-length, it 

 must also be possible to calculate the body-length from the pulse-frequency. For 

 this purpose the following is deduced from the foregoing formula: 



D - DN2 

 D '-NT 



These calculations, naturally, have only a theoretical interest, and it is obvious 

 that for purposes of comparison none but perfectly healthy individuals of the 

 same age and sex and living under absolutely identical conditions must be selected. 



(c) Of other factors that influence the frequency of the pulse, it has been 

 observed that muscular activity, heightening of the arterial blood-pressure, in- 

 gestion of food, elevation of temperature, pain, unpleasant sensations in the 

 alimentary tract, nausea, and psychic or sexual excitement accelerate the pulse. 



Further, the pulse is somewhat more frequent in the standing position (also 

 when the body is raised passively) than in the recumbent posture. Music accel- 

 erates the heart-beat in man and in animals and at the same time raises the 

 blood-pressure. Exposure to increased atmospheric pressure diminishes the 

 pulse-frequency. In the latter condition the first elasticity-elevation more 

 nearly approaches the summit. 



^ (d) The diurnal periodicity of the pulse-frequency is of especial interest. The 

 variations rarely exceed a few beats and in a general way they correspond with 

 the course of the temperature-curve. According to Haun the pulse is most fre- 

 quent with the advent of winter and is least frequent with that of summer. 



(e) Frequency of the pulse in various animals: Elephant 28, high-bred stallion 

 about 30 (in mares and work-horses it is a little higher), neat cattle about 50, 

 sheep and swine 75, dog 95, cat 130, rabbit from 120 to 150 in one minute. 



