Influence of Habitual Exercise and Hormone Replacement Therapy on Carotid Artery Imtima-Media Thickness

Carotid artery intima-media thickness (IMT) is an independent risk factor for cardiovascular disease (CVD). Habitual exercise and chronic hormone replacement therapy (HRT) are associated with a lower risk of CVD in postmenopausal women. This cardioprotective benefit may be mediated through favorable influences on carotid IMT. Using a cross-sectional study design we determined the respective and interactive effects of habitual exercise and HRT on carotid IMT (B-mode ultrasound) in 43 healthy postmenopausal women: 9 sedentary HRT nonusers (65 ± 2 yr; mean ± SE), 12 sedentary HRT users (58 ± 2), 8 endurance-trained HRT nonusers (61 ± 3), and 14 endurance-trained HRT users (64 ± 2). There were no differences in carotid IMT and IMT/lumen ratio between sedentary and endurance-trained women, or between users and nonusers of HRT. Carotid artery systolic blood pressure (applanation tonometry) and traditional atherosclerotic risk factors were not different among the groups. We conclude that neither habitual exercise status nor chronic HRT use status are associated with lower levels of carotid IMT in healthy post-menopausal women. As such, the protective effects of habitual exercise and HRT against CVD may not be exerted through favorable influences on carotid IMT. The absence of a clear modulatory influence on carotid IMT may be due to a lack of effect on carotid artery systolic blood pressure. Support: NIH AG00847, HL03840, and HL07852.