EXERCISE TRAINING INCREASES TOTAL SYSTEMIC ARTERIAL COMPLIANCE IN HUMANS

Using a noninvasive technique we have investigated the effect of 4 wk of exercise training on total systemic arterial compliance (SAC) in 13 previously sedentary young males. SAC is assessed from simultaneous measurements of ascending aortic blood velocity using Doppler velocimetry and surrogate estimates of aortic root pressure obtained by applanation tonometry of the right carotid artery. Subsequent calibration of the pressure waveform is by linear interpolation against brachial arterial pressures measured sphygmomanometrically. Exercise training increased the overall mean maximum oxygen consumption (VO2max) by 5.1 ml.min(-1).kg(-1) (95% confidence limits 1.30-8.80, P < 0.01) and decreased mean systolic blood pressure by 8.4 mmHg [95% confidence interval (CI) 2.9-13.9, P < 0.01]. Mean SAC increased by 0.26 units (95% CI 0.10-0.43, P < 0.01) with the regional stiffness of the aortic arch (measured echocardiographically using the p-index) showing a complementary decrease of 1.03 (95% CI -2.25-0.19, P < 0.05). Assuming a logarithmic arterial volume-pressure relationship, we were able to dissociate the change in SAC due to the exercise training-induced decrease in blood pressure from that due to change in the intrinsic compliance of the systemic arteries. Our results indicate that 1) exercise training increases SAC; 2) that the increase in SAC is greater than that due to changes in blood pressure and is likely to include a component due to change in intrinsic arterial compliance; and 3) that the induced change in SAC is linearly related to change in VO2max.