Inverse relationship between cardiorespiratory fitness and carotid atherosclerosis

The association between cardiorespiratory fitness (VO2max) and carotid atherosclerosis was analyzed in 163 men, aged 50 to 60 years. VO2max was assessed using breath-by-breath respiratory gas analyses during maximal exercise stress test. Atherosclerosis was evaluated quantitatively as intima-media thickness (IMT) of the right and left carotid arteries by high-resolution B-mode ultrasonography. Mean VO2max was 29.6 ml/kg per min (95%CI 28.7;30.5), common carotid IMT 1.04 mm (95%CI 1.01;1.07) and carotid bifurcation IMT 1.73 mm (95%CI 1.66;1.81). VO2max correlated inversely with carotid bifurcation IMT (r = -0.31, P < 0.001), but not with common carotid IMT (r = -0.13, P = 0.102). Men in the highest quartile of VO2max had lower (P < 0.001) bifurcation IMT 1.51 mm (95%CI 1.41;1.61) than men in the lowest (1.95 mm (95%CI 1.75;2.16)) and in the second lowest VO2max quartile (1.79 mm (1.63; 1.95)). The difference persisted (P = 0.014) after controlling for age, LDL-cholesterol, systolic blood pressure, saturated fat intake, current health status and exercise-induced ST-segment depression. These data suggest that cardiorespiratory fitness is an important independent predictor of carotid atherosclerosis in middle-aged men.