FACTORS ALTERING CONCENTRATION OF BLOOD LIPIDS 425 



normal weight. Similar conclusions can be reached on the basis of the 

 work of Bruger and Poindexter, 409 as well as of that of Rony and Levy. 344 

 Moreover, no correlation was found between weight changes in obese 

 subjects and the concentration of their blood lipids. 213 - 414 It is believed 

 that reductions of blood fat occurring during the period when a loss of body 

 weight is observed 213,411 are referable to the manner in which reduction 

 was effected, rather than to the loss of fat in itself. 202 Nissen 415 reported 

 that a greater increase in blood fat occurs in obese than in normal persons 

 after fat is fed. 



The inability to demonstrate a correlation between blood lipids and obes- 

 ity is to be expected. No greater rate of utilization of fat occurs in obesity 

 than in normal conditions; in all probability the opposite situation obtains. 

 Since fat is not being oxidized in unusual amounts in obese individuals, no 

 increased transport of the lipids from the fat depots to the liver is required ; 

 hence, a hyperlipemia does not occur. The fact that the metabolism of 

 fat is slower in the obese male during fasting is indicated by the experi- 

 ments of Deuel and Gulick 408 in which the single subject who was overweight 

 exhibited the lowest level of ketonuria. 



(5) The Effect of Work on the Level of Blood Lipids 



A number of investigators have shown that an increase in blood lipids 

 accompanies hard work. Gage and Fish 3 first reported that an increase in 

 the chylomicron count in the blood occurred concomitantly with exercise. 

 This would indicate that a rise in the neutral fat level had taken place. 

 Stewart et a/. 416 likewise reported an increase in blood lipid after strenuous 

 exercise; they believe that only the triglyceride fraction (neutral fat) is 

 involved. Several other workers 300 ? 417 have also reported an increased 

 lipemia as a result of heavy energy output. On the other hand, Hira- 

 matsu 418 found no change in the blood fat of rats following exercise, if 

 they had been on a rice diet. However, if the previous dietary regimen 

 had been largely protein, a marked decrease in blood lipids resulted after 

 exertion. 



Reports on the effect of hard work on blood cholesterol levels are con- 

 flicting. Robinson and co-workers 419 reported a marked drop in chole- 



414 C. A. Poindexter and M. Bruger, Arch. Internal Med., 56, 884-890 (1935). 



415 N. I. Nissen, Acta Med. Scand., 73, 99-124 (1930). 



416 C. P. Stewart, R. Gaddie, and D. M. Dunlop, Biochem. J., 25, 733-748 (1931). 



417 J. R. Murlin and J. A. Riche, Am. J. Physiol, 40, 146 (1916). 



418 T. Hiramatsu, Biochem. Z., 255, 304-305 (1932). 



419 S. H. Q. Robinson, W. R. Brain, and H. D. Kay, Lancet, 1927, II, 325-326. 



