164 
MUSCULAR WORK 
for each day, and the severe work from 420 to 660 calories. In the 
very severe work experiment, the riding period began at 8 h 01 m a.m. of the first 
day and ended at 3 h 01 m a.m. of the following. During this time the subject 
rode the bicycle ergometer approximately 11 hours in all," the heat equivalent 
of the muscular work being 957 calories. 6 When he stopped work at 3 h 01 m 
a.m., he changed his underclothes and lay down; the observer reported him 
to be asleep at 3 h 20 m a.m., the measurements of the metabolism after 
work given in table 135 beginning at 4 a.m. The influence of the pre- 
ceding muscular activity on the metabolism is strikingly shown in these 
results. 
Table 135. — Heat produced during sleep (1 a.m. to 7 a.m.) following different 
conditions of activity, as reported by Benedict and Carpenter. 1 
' [Average per hour.] 
Subject. 
Sleep 
after 
rest. 
Sleep 
after 
moderate 
work. 
Sleep 
after 
severe 
work. 
Sleep 
after 
very 
severe 
work. 
E. O 
JF. S 
J. c. w.... 
B. F. D.... 
A. L. L.... 
cals. 
69.3 
60.4 
77.2 
69.8 
78.3 
cals. 
74.8 
65.3 
cals. 
83.'l 
83.3 
83.7 
cals. 
97.9 
1 All work ceased at least 7 hours before metabolism measurements began except in 
the case of the very severe work in which work ceased but 1 hour before. 
According to data presented for the subject J. C. W. by Benedict and 
Carpenter, the average heat production from 1 a.m. to 7 a.m. with food at 
rest was 449 calories. The data of the work experiments with this subject d 
show that the amount of external muscular work was equivalent to approxi- 
mately 586 calories per day, the calorie output in the 6 experiments from 
1 a.m. to 7 a.m. being as follows: 528, 527, 534, 475, 503, 487, with an average 
for the 6 experiments of 509 calories. This represents an increment over the 
resting value of 60 calories or about 13 per cent, that is, during the period 
which began at least 7 or 8 hours after the muscular work had finished, the 
metabolism was still some 13 per cent above the normal. Aside from the ex- 
periment with A. L. L., none of these work experiments can be considered as 
a severe draft upon the subjects. The work was done easily, particularly by 
J. C. W., who was a college champion and an excellent amateur athlete. 
The muscular activity cannot therefore be considered as at all fatiguing or 
done under abnormal conditions. 
In strong contrast with the results found in the Middletown respiration 
apparatus are those almost invariably 6 reported by the investigators of the 
Zuntz school. The most recent and complete digest of the opinions of these 
workers is that which has been given by Loewy. Loewy f contends that the 
increase in the oxygen consumption during the whole period following work is 
approximately equal to the total consumption during one minute of the work- 
a Benedict and Milner, U. S. Dept. Agr., Office Exp. Stas. Bui. 175, 1907, p. 105. 
6 Benedict and Milner, loc. cit., p. 333. 
c Benedict and Carpenter, U. S. Dept. Agr., Office Exp. Stas., Bui. 208, 1909, p. 22. 
a Benedict and Milner, U. S. Dept. Agr., Office Exp. Stas. Bui. 175, pp. 332 and 307. 
e After this was written and in proof, a paper appeared by Durig and Zuntz (Die Nachwirkung der Arbeit auf 
die Respiration in groesseren Hoehen. Skand. Archiv, 1913, 29, p. 133) in which they give more marked 
results than any that they have hitherto published. 
/ Loewy, in Oppenheimer's Handbuch der Biochemie, Jena, 1911, 4, (1), p. 263. 
