Unfavorable effects of resistance training on central arterial compliance: a randomized intervention study.

BACKGROUND Reductions in the compliance of central arteries exert a number of adverse effects on cardiovascular function and disease risk. Endurance training is efficacious in increasing arterial compliance in healthy adults. We determined the effects of resistance training on carotid arterial compliance using the intervention study design. METHODS AND RESULTS Twenty-eight healthy men 20 to 38 years old were randomly assigned to the intervention group (n=14) and the control group (n=14). Control subjects were instructed not to alter their normal activity levels throughout the study period. Intervention subjects underwent 3 supervised resistance training sessions per week for 4 months and detraining for a subsequent 4 months. The resistance training increased maximal strength in all muscle groups tested (P<0.001). There were no significant differences in baseline arterial compliance and beta-stiffness index between the intervention and control groups. In the intervention group, carotid arterial compliance decreased 19% (P<0.05), and beta-stiffness index increased 21% (P<0.01) after resistance training. These values returned completely to the baseline levels during the detraining period. Arterial compliance did not change in the control group. In both groups, there were no significant changes in brachial and carotid blood pressure, carotid intima-media thickness, lumen diameter, and femoral arterial compliance. Changes in carotid artery compliance were significantly and negatively related to corresponding changes in left ventricular mass index (r=-0.56, P<0.001) and left ventricular hypertrophy index (r=-0.68, P<0.001). CONCLUSIONS In marked contrast to the beneficial effect of regular aerobic exercise, several months of resistance training "reduces" central arterial compliance in healthy men.