Lipid metabolism in relation to exercise and lipoprotein lipase activity

Regular exercise is thought to prevent and improve control of metabolic diseases such as dyslipidemia, obesity and diabetes mellitus, through increasing energy consumption and improving metabolism. In general, the blood levels of triglycerides (TG) decrease and the blood levels of high-density lipoprotein cholesterol (HDL-C) increase after exercise training. This is likely because the activity of muscle lipoprotein lipase (LPL) increases during exercise, and the TG in the very low density lipoprotein (VLDL) are hydrolyzed by LPL and released as free fatty acids (FFA), which are incorporated into the muscle cells and consumed. Exercise is thought to greatly improve hypertriglyceridemia and hypo-HDL-cholesterolemia in patients with dyslipidemia, and its effect is thought to be particularly remarkable in obese patients with diabetes mellitus. Exercise appears to prevent the development of atherosclerosis and reduce the risk of such associated diseases as myocardial infarction and cerebral infarction, by simultaneously decreasing the blood levels of TG and increasing those of HDL-C. In addition, exercise appears to promote TG degradation by increasing the muscle LPL activity and also to promote burning of fat through increasing the cellular expression of uncoupling protein 3 (UCP3), resulting in improvement of obesity and insulin resistance. Thus, exercise appears to prevent and improve metabolic diseases such as diabetes mellitus, atherosclerosis/atherosclerotic diseases and obesity, by activating skeletal muscle LPL activity.