Blood lipid and lipoprotein concentrations in active, sedentary, healthy and diseased men

To examine differences in resting blood lipid and lipoprotein concentrations in male subjects of varying degrees of cardiovascular fitness ranging from the healthy elite athlete to the sedentary subject either with or without angiographically confirmed evidence of coronary artery disease (CAD).

Two-hundred-and-eighty-four clinically asymptomatic male subjects were selected from a group of Olympic distance runners (n = 1 7), physical education athletes (n = 44), and industrial executives (n = 223). Each subject received a detailed physical examination and provided a venous blood sample after fasting, which was analysed for lipid and lipoprotein concentrations. Maximum oxygen uptake was determined using on-line computerised respiratory analysis during a functional diagnostic test. The industrial executive group was further divided according to their electrocardiographic (ECG) response to exercise; negative ECG (n = 138), positive (abnormal) ECG but no angiographic evidence of CAD (n = 18) and positive ECG with angiographic evidence of significant CAD (n=67).

Lipid-lipoprotein profiles were consistently abnormal in subjects with a positive ECG and documented evidence of CAD, whereas those subjects who tested negative or false-positive were less affected. The lipid-lipoprotein profiles observed between Olympic distance runners and an age-matched group of physically active students were not significantly different despite clear differences in physical activity patterns.

In addition to the abnormal lipid-lipoprotein profile in subjects with CAD, the present data also suggest that while physical activity confers metabolic cardioprotection, a threshold stimulus exists beyond which no further benefits can be gained.