The effect of physical activity on lipid and lipoprotein levels.

There is more than an intuitive link between the adoption of a sedentary lifestyle and an increase in cardiovascular disease. Physical activity has been associated with a reduced incidence of coronary mortality in cross-sectional and prospective studies. However, an independent relationship between exercise, fitness, and the level of total cholesterol, HDL-C, and triglycerides has been difficult to establish. The effects of training on these parameters may occur only as a consequence of alteration in body habitus, diet, smoking, or ethanol and medication use. Evidence to date suggests that persons with higher cholesterol, LDL-C, and triglyceride levels, as well as individuals with lower HDL-C levels, have favorable changes in these measurements after either endurance or resistive exercise training. Mechanisms that include metabolism and catabolism of lipid and lipoproteins have been discussed. The finding that self-report of vigorous activity, rather than treadmill time, correlates well with favorable lipoprotein levels suggests that performance of physical work, not necessarily aerobic training, is responsible for these alterations. The exercise dose (intensity, duration, frequency) and total time period necessary, as well as mechanism of lipid and lipoprotein change, requires further elucidation.