PULSE. 



189 



Reports, No. VII. It will be sufficient to 

 state, that in the inverted position of the body 

 the pulse becomes less frequent, especially in 

 persons accustomed to this unusual posture. 

 In two such instances the difference between 

 the erect and recumbent postures equalled 

 that between the recumbent and the inverted 

 postures, being in both cases 15 beats. 



The following is a short summary of the 

 leading facts relating to the effect of posture 

 on the pulse. 



1. In the healthy adult male the mean 

 numbers of the pulse are as follows: Stand- 

 ing, 79; sitting, 70; lying, 67; including all 

 exceptions to the rule. Standing, 81; sitting, 

 71 ; lying, 66 ; excluding all exceptions to the 

 rule. 



2. In the healthy adult female the numbers 

 are: Standing, 89; sitting, 82; lying, 80; 

 including all exceptions to the rule. Standing, 

 91 ; sitting, 84 ; lying, 80; excluding all ex- 

 ceptions to the rule. 



3. In both sexes the extremes are very 

 remote from the mean results, and the ex- 

 ceptions to general rules very numerous. 



4. In both sexes, also, the effect of change 

 of posture increases as the frequency of the 

 pulse increases; but the exceptions to general 

 rules are more numerous as the pulse is less 

 frequent. 



5. The effect of change of posture on any 

 given frequency of the pulse is much greater 

 in the male than in the female. 



6. The effect of change of posture on the 

 pulse is less in early youth than in the adult, 

 and the modifying influence of age is greater 

 in the female than in the male. 



7. The exceptions to general rules are more 

 numerous in early youth than at the adult age. 



8. The exceptions to general rules are more 

 numerous as the effect of change of posture is 

 less. 



9. The effect of change of posture on the 

 pulse is greater in the forenoon than in the 

 afterpart of the day. 



10. The inverted posture of the body les- 

 sens the frequency of the pulse. 



11. The varying frequency of the pulse in 

 different postures of the body is due to mus- 

 cular contraction. 



EXERCISE. Muscular exertion increases 

 the frequency of the pulse more than any 

 other cause, as will sufficiently appear by the 

 following quotation from Bryan Robinson.* 

 " The pulse, in a minute, of a man lying, 

 sitting, standing, or walking at the rate of two 

 miles in an hour, at the rate of four miles in 

 an hour, or running as fast as he could, were 

 64, 68, 78, 100, 140, and 150 or more." 

 Change of posture, as has just been proved, 

 forms merely a particular case of muscular 

 effort. The act of changing from one posture 

 to another, and the maintenance of different 

 positions by the action of the muscles, both 

 occasion an increased frequency of the pulse ; 

 so also does the stretching out of the arm or 

 the holding of it in the same posture, the 



* Op. cit. p. 177. 



pulse rising rapidly with the continuance of 

 the effort, and falling, as the writer has proved 

 experimentally, on returning to a state of rest, 

 below the frequency which it had before 

 the effort was made ; and the same obser- 

 vation applies to fatigue induced by long con- 

 tinued exertion, as in walking. The cause of 

 the increased frequency of the pulse which 

 attends muscular effort is partly mechanical, 

 that is to say, depending on the rapid pro- 

 pulsion of the blood through the large veins, 

 and partly due to the effort of the will which 

 sets the muscles in action. It is probable, 

 however, that the first-named cause is by far 

 the most influential. 



Passive exercise, as in riding and the various 

 forms of carriage conveyance, has also a 

 marked effect on the pulse ; an effect partly 

 due to the varying action of the muscles in 

 supporting the different postures into which 

 the body is being constantly thrown, and partly 

 to a cause correctly pointed out by Dr. Ar- 

 nott in the following passage. 



" In a long vein below the heart, when the 

 body falls, the blood, by its inertia and the 

 supporting action of the vessels, does not fall 

 so fast, and therefore really rises in the vein ; 

 and as there are valves in the veins preventing 

 return, the circulation is thus quickened with- 

 out any muscular exhaustion on the part of 

 the individual. This helps to explain the 

 effect of the movement of carriages, of vessels 

 at sea, of swings, &c., and the effect on the 

 circulation of passive exercise generally, and 

 leaves it less a mystery why these means are 

 often so useful in certain states of weak 

 health."* 



TIME OF DAY DIURNAL VARIATIONS OF 

 THE PULSE. This subject demands a more 

 minute examination than it has yet received ; 

 for it is extremely interesting in a physiolo- 

 gical point of view. All the older and several 

 comparatively modern authorities agree in 

 representing the pulse as more frequent in the 

 evening than in the morning. Hallerf, Rye 

 and Schwenkej, Gregory*), Zimmerman ||, 

 Hufelandf, Quetelet**, Fodereff, Falco- 

 ner Jt, Double, and Cullen, and, among mo- 

 dern physiologists, Dr. Bostock ^, describe an 

 increase of frequency towards evening ; and 

 more than one of these authors speak of a 

 similar change occurring at noon and in the 

 afternoon. Cullen especially insisted on this 

 latter circumstance. 



It will facilitate our inquiry if we confine 

 our attention for the present to the frequency 

 of the pulse in the morning and in the even- 

 ing, or in the earlier and later periods of the 

 day, reserving the alleged increase of frequency 



* Elements of Physics, vol. i. p. 52. 

 f Opera Physiologica, Sectio 2, xvii. 

 j Quoted by Haller, as above. 

 Conspectus Medicinse Theoreticse, cap. xv. 

 ccccliii. 



|| On Experience in Physic, vol. i. p. 250. 



^f Makrobiotik, p. 53. 



** Essai sur 1'Homme Moyen, torn, ii, p 88. 



ft Esai de Physiologic Positive, torn. i. p. 190. 



jt Op. cit. p. 24. 



Cyclopaedia of Practical Medicine, art. Pulse. 



