PHYSICAL-ACTIVITY AND LIPOPROTEIN LIPID DISORDERS

Working muscle plays a central role in the control of lipid metabolism . Increased physical activity induces a number of positive changes in the metabolism of lipoproteins: serum triglycerides are lowered by the increased lipolytic activity and the production of native high densit y lipoprotein (HDL) particles is increased. The increased lecithin : c holesterol acyltransferase activity leads to an increased production o f HDL2, which in addition is catabolised more slowly due to a decrease d activity of hepatic lipase. The 3 effects explain the increased HDL levels of endurance trained individuals. These effects have been demon strated in cross-sectional as well as longitudinal studies by differen t groups, and can be induced by training, independent of changes in bo dyweight. The influence of endurance activity on the quality and quant ity of low density lipoprotein (LDL) particles is a further reason for the antiatherogenic potential of increased physical activity. It has been shown by several groups that small dense LDL particles represent a particular risk factor for atherosclerosis. Recent studies presented strong evidence that LDL level and composition can be influenced favo urably by physical activity. In addition to the direct influence of ph ysical activity on lipids and lipoproteins, physical exercise may impr ove the disturbances of haemorheological factors, particularly those a ssociated with hypertriglyceridaemia. In conclusion, there is increase d evidence that physical activity is able to favourably influence all 3 components of the atherogenic lipoprotein phenotype: the HDL concent ration increases, the concentration of small dense LDL decreases, and serum triglycerides are reduced.