Cholesterol is a fatty substance that is an important component of cell membranes, steroid hormones, vitamin D and nerve coverings. It is carried in the bloodstream by lipoproteins. Low-density lipoprotein (LDL) transports cholesterol from the liver to tissues throughout the body. Excessive levels of LDL can’t be used by the tissues and are deposited in the blood vessels, causing arterial disease. High-density lipoproteins (good cholesterol) transport unused cholesterol back to the liver for recycling. Aerobic exercise increases HDL, which helps prevent arterial disease. The effects of weight training on HDL and LDL metabolism are less well known. Brazilian scientists found that resistance exercise accelerated metabolism of LDL cholesterol, but had no effect on HDL. Weight training has positive effects on blood fat metabolism, but they are not as great as aerobic exercise.
Source: Atherosclerosis, published online