The relationships between different levels of participation in physical activity and biological indices of cardiovascular risk were examined in a sample of 6814 male and female adults who took part in a national risk factor prevalence survey. Participation in physical activity was classified as “aerobic” (14.6% of total), “moderate” (53.6%) or “inactive” (31.8%). Bivariate analyses found significant associations between level of exercise participation and diastolic blood pressuresIn men, but not in women; significant associations were found between reported physical activity and systolic blood pressure, total serum cholesterol, high‐density lipoprotein (HOL) cholesterol, HOLltotal cholesterol ratio and trlglycerides for both men and women. Further analyses were controlled for age, education, and the survey site, which were potential confounders of the association between physical activity and other coronary heart disease risk factors. After adjustment, significant associations remained between levels of exercise participation and HDL cholesterol level, HOLltotal cholesterol ratio and serum triglyceride levels for both sexes. In women, there was also a significant relationshipbetween activity level and bodymass index. In addition, for men only, there was a significant inverse relationship between physical activity and total cholesterol, and, for older men, between physical activity and systolic blood pressure. It is well recognised that physical activity has an independent effect on reducing the risk of coronary heart disease. The resultsof thisstudysuggestthat there may be small supplementary effects mediated through the relationship between exercise and other biological cardiovascular risk factors.