METABOLISM WITH GRADE WALKING. 



241 



about 2.25 calories when E. D. B. walked at 35 to 40 meters per minute, 

 and about 6.25 calories when he walked at 75 to 80 meters per minute. 

 These changes may be calculated on a percentage basis by referring 

 to the values in column m of table 56 (p. 221) . Thus, a change in speed 

 from 35-40 meters per minute to 75-80 meters per minute increased the 

 heat-output over that requhed for standing and the horizontal com- 

 ponent 0.42 calorie, or 60 per cent, with a 5 per cent grade; 1.76 calo- 

 ries, or 108 per cent, with a 10 per cent grade; 2.29 calories, or 92 per 

 cent, with a 15 per cent grade; and 4.30 calories, or 139 per cent, 

 with a 20 per cent grade. When the subject was walking with a speed 

 of 35 to 40 meters and on a 5 per cent grade, the heat-output due to 

 grade walking averaged 0.70 calorie. When he changed to a grade of 

 10 per cent without change of speed, the heat-output increased 0.93 

 calorie, or 133 per cent; with a 15 per cent grade, the increase over the 

 5 per cent value was 1.8 calories, or 257 per cent; and with a 20 per 

 cent grade, 2.39 calories, or 341 per cent. Similarly, when the speed of 

 walking was 75 to 80 meters per minute, the percentage increases over 

 the 5 per cent grade were 203 per cent for the 10 per cent grade, 328 per 

 cent for the 15 per cent grade, 560 per cent for the 20 per cent grade, 

 and 729 per cent for the 25 per cent grade. 



INCREMENT IN HEAT PER KILOGRAMMETER OF WORK DONE IN GRADE-LIFT. 



From the increment in the heat-output due to the grade and the 

 total kilogrammeters of work due to the grade-lift, the heat outlay per 

 kilogrammeter of work done in the elevation of the body has been 

 computed and recorded in column p of tables 52 to 55. A summary 

 of the daily averages is given in table 65. A. J. 0., with only one 



TABLE 65. Average increment in heat-output due to grade-lift per 



kilogrammeter of work. 



experiment of two periods, shows the lowest average value, or 5.6 

 gram-calories. This was for the low grade of 3.6 per cent, with but 

 172 kg. m. of work. The total heat-output was correspondingly low 

 and the proportionate probability of error on deducting the values for 

 the standing and horizontal walking requirements was naturally large. 



