Physical Activity has been suggested to have favorable effects on various cardiovascular risk factors, and may serve as an intervening variable in life-style intervention studies. We aimed to examine the relationship between habitual physical activity and selected cardiovascular markers at baseline in a sample of overweight women who participated in the SMART clinical trial [ACTRN12608000425392]. A sub-sample of eighty-six overweight/obese women (mean age ± S.D.: 45 ± 7.9 years) were included in this analysis. Anthropometric and fasting blood data was collected at baseline (t = 0). Habitual physical
activity was assessed by a validated questionnaire (Baecke questionnaire). Associations were examined by Pearson correlation, and quartile differences by one-way ANOVA. The results showed that higher levels of habitual physical activity was associated with higher HDL cholesterol (HDL-C) (p = 0.031) and lower insulin logarithm value (p = 0.008). Women in the highest quartile of activity had a mean fasting HDL-C of 1.67 mmol/L and fasting insulin of 8.5 mU/L, compared with fasting HDL-C of 1.39 mmol/L and fasting insulin of 13.7 mU/L in the lowest quartile. Weight, body mass index, systolic blood pressure, diastolic blood pressure, fasting total cholesterol, low-density lipoprotein cholesterol, total triglyceride, or glucose levels were not significantly associated with habitual physical activity in this study. The findings suggest that habitual physical activity is likely to be an important intervening variable for fasting HDL cholesterol and insulin in this sub-sample of the clinical trial.