Effects of exercise and food restriction on serum cholesterol and liver lipids

Abstract

The effect of 15 weeks of regular, vigorous exercise (swimming) on serum and hepatic cholesterol in rats was studied. The effect of exercise on body composition and the interrelation of body composition and serum and hepatic cholesterol was also investigated. Caloric restriction without exercise was imposed on another group of rats in an effort to produce animals with body composition similar to those subjected to exercise. The calorie-restricted animals were retarded in growth as evidenced by lower ash weight but their body composition on a percentage basis was almost identical to the ad libitum fed animals who were not exercised. It was concluded that: 1) Exercise was effective in preventing most of the increase in body fatness and serum cholesterol concentration associated with an increase in age. 2) Neither total nor free cholesterol concentration in the liver was affected by exercise, but the concentration of total hepatic lipids was reduced. 3) Body fatness, serum cholesterol, and concentration of total hepatic lipids were all positively correlated with each other and inversely related to weight of the adrenal glands in the animals.

Weight Loss and Lipid Changes in Overweight Subjects

“…Although in both groups the plasma cholesterol falls in the average range which we have found in a larger sample [12], the average plasma cholesterol in group II (of heavier individuals) is higher than in group I. This relationship between over weight and plasma cholesterol, although weak, has been demonstrated repeatedly [13,14,15]. Montoye et al [16] found also a low but statistically significant relationship between serum cholesterol levels and body fatness, even at an early age and particularly among men.…”

Effects of weight changes produced by exercise, food restriction, or overeating on body composition

“…Similarly, in studies on growing rats, animals which exercised regularly were found to be leaner than sedentary animals that had their food intake restricted so that they gained weight at the same rate as the exercisers (7,8). These observations suggested the possibility that exercise might protect against the loss of lean tissue that can occur when an individual is in negative caloric balance.…”

Effects of exercise and thyroxine on cholesterol and fatty acid synthesis in aging rats

“…High levels of physical activity have been associated with decreased lipid levels and a decreased incidence of atherosclerosis in man (Golding, 1961;Holloszy ^ al., 1964). Although results of animal studies have not been as conclusive as with human studies, a similar effect of exercise has been observed in experimental animals (Jones et , 1964;Gollnick and Simmons, 1967), There is evidence that the effects of exercise may be mediated by the thyroid gland.…”