Effect of physical exercise on erythrocyte lipids, biliary cholesterol and bile lithogenicity in rats.

Male Wistar rats were exercised (E) by daily 1 h swimming for 24 days. Sedentry controls (S) were caged individually. Bile analysis at the end of the experiment (24 h after the last exercise) showed a decrease in bile cholesterol (CH) (P less than 0.02) and phospholipids (PL) (P less than 0.01) in the exercising animals, but no significant change in the bile acids (BA). These changes in the exercising rats resulted in a decreased CH saturation of bile: in an improvement in the (BA + PL)/CH ratio (P=0.05) and a trend to a decrease in the per cent saturation of bile CH. Exercise did not affect the bile flow or bile acid flux rate. Exercise decreased erythrocyte phospholipids (P less than 0.01). The effect of exercise on bile was associated with a trend to lower CH in the erythrocytes and in the adipose tissue and thus most likely does not represent a shift of cholesterol from the liver to the peripheral tissues. Physical exercise may be a preventive factor in cholesterol gallstone formation.