PULSE-RATE. 453 



in connection with another series of observations in this laboratory, 

 the results of which are being prepared for pubHcation. 



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 uni- 

 formly 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. 



INFLUENCE UPON PULSE-RATE OF WORK ON BICYCLE ERGOMETER, WITH SPECIAL 

 REFERENCE TO RETURN TO NORMAL. 



One of the best indices of general physical condition is supposed to 

 be the rapidity with which the pulse returns to normal after exercise. 

 In connection with the extensive series of observations carried on at 

 the Y. M. C. A. College by Professors McCurdy and Berry, the inves- 

 tigation of Professor Johnson on the pulse-rate after work on a bicycle 

 ergometer had special significance, since our subjects were for most of 

 the time on reduced diet and a control squad was available for normal 

 data. The men rode a bicycle ergometer,^ at the rate of 80 revolutions 

 per minute for exactly 5 minutes and with a current of 1.35 amperes 

 through the field. Using the data secured in the calibration tests of 

 this ergometer, as published by Benedict and Cady, Professor Johnson 

 has computed that the total amount of work performed by each subject 

 is as follows: 



"When the pedal revolution is 80 per minute and the current 1.35 amperes, 

 the heat produced per revolution is 0.0198 large calorie. In 5 minutes there 

 are 400 revolutions, producing 7.92 calories.^ The mechanical equivalent 

 of heat is taken as 427.3 kilogrammeters for each calorie. Multiplying, 

 the result is 3,384 kilogrammeters." 



This corresponds to 11.3 kilogrammeters per second, and if con- 

 verted to foot-pounds, equals 81.6 foot-pounds or about one-seventh 

 horsepower. To give some idea of the approximate amount of work 

 performed in common terms, this would be equivalent to the work 

 done by an individual weighing 163 pounds climbing a 6-inch step 

 every second and attaining an elevation of 150 feet in 5 minutes. 



Of special importance, however, is the fact that every subject, in 

 both Squads A and B, performed exactly the same amount of work. 



» Benedict and Cady, Carnegie Inst. Wash. Pub. No. 167, 1912. (See description of ergometer 

 11, p. 6.) - _ _ 



* This amount of external muscular work corresponds to about 1.5 calories, and is thus com- 

 parable with the amount of work employed in some earlier experiments, gee Benedict 

 and Cathcart, Carnegie Inst. Wash. Pub. No. 187, 1913, p. 154. 



