308 CARNEGIE INSTITUTION OF WASHINGTON. 



(15) Energy transformations during horizontal walking. Francis G. Benedict and Hans 



Murschhaiiser. Publication No. 231, Carnegie Institution of Washington 

 (1915). 



The main object of this research was to studj'^ the increase in metabolism 

 due to walking on a level at increasing speeds. A complete historical review 

 is given of all previous research in which the gaseous metabolism during hori- 

 zontal walking has been studied, including a large summary table in which the 

 results of 20 different investigations are recorded and compared on the basis of 

 the movement of 1 kilogram over 1 meter of level path, i. e., 1 horizontal 

 kilogrammeter. 



With the universal respii-ation apparatus and a special type of treadmill 

 designed and constructed in the Nutrition Laboratory by E. H. Metcalf, a study 

 was made in the fall of 1913 and the spring of 1914 of the gaseous metabolism 

 of two subjects during horizontal walking. Determinations were made of the 

 carbon-dioxide production, the oxygen consumption, and the distance walked 

 by the subject; records of the respiration-rate were obtained automatically 

 by a special tambour arrangement; a few records of pulse-rate were secured 

 with the Bock-Thoma oscillograph and the Einthoven string galvanometer; 

 the exact number of steps taken were recorded automatically by a step- 

 counter; and finally, the height to which the body was raised during walking 

 was measured by a work-adder wheel by means of which each upward and 

 downward movement of the body was recorded upon a rotating kymograph 

 drum. 



To establish a base-line for comparison with the metabolism during walking, 

 preliminary experiments were made with the subject (1) standing with body 

 relaxed without external support; (2) leaning against a support at the back; 

 (3) leaning on a staff; and (4) standing with muscles tense in the position of 

 "attention." A few experiments were also made with the subject standing 

 and swinging the arms from side to side as in a fast walk, and with the subject 

 sitting and lying. 



In the walkijQg experiments the subject walked at a very slow speed, a 

 medium speed, or a very fast speed, and in a few experiments actually ran, 

 thus giving data for comparing the work of forward progression while the sub- 

 ject was walking with that while he was running. A study was also made of the 

 effect on metabolism of fatigue due to long-continued walking. 



Usually both the standing experiments and the walking experiments were 

 made during the post-absorptive state, when the subject had no food in the 

 stomach, but the influence of both heavy and light meals upon the metabolism 

 was also studied. In a few experiments the diet was controlled, a special 

 protein, carbohydrate, or fat diet being supplied. In the observations both 

 with and without food the heat per horizontal kilogrammeter was found to be 

 practically independent of the taking of food; an increase in the energy per unit 

 was noted as the speed increased and a considerable less energy per unit when 

 the subject was running as compared with that when he was walking. 



The report concludes with an analysis of the mechanics of locomotion. 



(16) The effect of certain drugs on the respiration and gaseous metabolism in normal human 



subjects. Harold L. Higgins and James H. Means. Journ. Pharmacol, and 

 Exp. Therapeutics, 7, 1 (1915). 



Observations are reported upon the alveolar carbon-dioxide tension, the res- 

 piration-rate, the ventilation of the lungs, and the gaseous exchange, and the 

 results of calculations are given of the volume of dead space in the breathing 

 of normal human subjects following the administration of drugs used in thera- 

 peutics, such as atropine, caffeine, camphor, strychnine, morphine, and heroin. 



