120 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



carried out for a number of years at the college under the direction of 

 Professor J. H. McCurdy and Professor Elmer Berry, a study was made 

 of the length of time required for the heart rate to return to normal after 

 a definite amount of muscular work. Use was made of a bicycle 

 ergometer belonging to the Nutrition Laboratory, which has been 

 described in detail in an earlier publication.^ This was shipped to 

 Springfield, there connected with a storage battery consisting of fifteen 

 1.5 volt Edison cells, and a mil-ammeter and sliding resistance placed in 

 circuit. By controlling the current passing through the fields of the 

 ergometer, holding it constant at 1.35 amperes, and adjusting the rate 

 of revolution of the pedals by means of a metronome beating 80 j)er 

 minute, the subjects performed a definite amount of work for a period 

 of 5 minutes. After mounting the ergometer, the man rode for an exact 

 period of 5 minutes at the rate of 80 pedal revolutions per minute. 

 Upon the completion of the 5-minute period, he lay down upon a 

 bench and the pulse-rate was counted for the first 15 seconds of every 

 minute until the normal resting pulse for the day was reached. 



MEASUREMENT OF GASEOUS METABOLISM DURING WORK. 



Measurements of the gaseous metabolism of man while engaged in 

 muscular work have been made by different investigators and include 

 such varied forms of work as riding a bicycle ergometer, lifting weights, 

 turning a wheel, and walking on a horizontal or inclined path both out- 

 of-doors and on a treadmill in a laboratory. In selecting the form of 

 muscular exercise for experiments on muscular work, walking seemed 

 most suitable on account of its being the natural and universal form of 

 exercise. It brings into play a large number of muscles of the body 

 and at the same time the element of training is practically negligible. 

 Furthermore, the Nutrition Laboratory was equipped with apparatus 

 for experiments in this line and considerable published and unpub- 

 lished data were available upon which to draw for necessary compari- 

 son. Accordingly, in addition to the work done with the ergometer, a 

 considerable number of observations were carried out with a treadmill. 

 The first set of experiments was made with Squad B on January 6 

 before their diet restriction began. This was followed with the same 

 squad on January 28 after a 20-day restriction of diet and on February 

 3 experiments were made with Squad A after four months of diet 

 restriction. In these experiments the subject walked a definite distance 

 at a definite speed and determinations were made of the carbon dioxide 

 excreted, and the oxygen consumed. 



Since the use of any form of mouth or nose appliance in metabolism 

 measurements is open to criticism and requires some practice to avoid 

 respiratory disturbances it was decided to build a closed chamber large 



1 Benedict and Cady, Carnegie Inst. Wash. Pub. No. 167, 1912, p. 5; see description of Er- 

 gometer No. II. 



