The role of lipoprotein manipulation in the treatment of atherosclerosis is well established. Improvement in lipoprotein cholesterol concentrations and subclass distribution through exercise training is often advised prior to pharmacologic intervention. As with other therapeutic interventions, dose must be stipulated to the patient. The dose of exercise training required to induce beneficial lipoprotein changes is unclear. This issue is further complicated by the potential effect of exercise training on lipoprotein subclass distribution (LDL I, LDL II, LDL III, LDL IV, HDL2a, HDL2b, HDL3a, HDL3b, HDL3c), enzymes, apoproteins, and transfer proteins and by the changes in diet and body composition that often accompany exercise training. These changes may be responsible for all or part of the lipoprotein change attributed to exercise. From available data, it appears that a threshold of approximately 15 miles.wk(-1) of jogging may be required to induce beneficial change.