Effects of resistance training on arterial stiffness: a meta-analysis

Background Regular aerobic exercise prevents and reverses arterial stiffening, but the association between resistance training and arterial stiffness is unclear. Aim This study was performed to conduct a systematic review and meta-analysis of randomised controlled clinical trials (RCTs) assessing the associations between resistance training and changes in arterial stiffness. Methods MEDLINE and SPORTDiscus databases were searched from January 1980 through to April 2011. RCTs evaluating the ability of resistance training to increase arterial stiffness in comparison with a control group were included in the meta-analysis. Two independent reviewers extracted data and assessed the quality of the included studies. Data from 185 reports of eight RCTs (193 participants) were included. Pooled mean differences in arterial stiffness indices (carotid arterial beta stiffness and pulse wave velocity (PWV)) between intervention and control groups were calculated using a random-effects model. Results The overall association of resistance training versus control with relative changes in carotid beta index or PWV (eight studies; 193 participants) was 10.7% (95% CI 3.4% to 18.0%; I-2, 89%; heterogeneity, p<0.001). Five studies indicated that resistance training in young subjects (n=115) was significantly associated with an increase in stiffness index of 14.3% (95% CI 8.5% to 20.1%; I-2, 71%; heterogeneity, p<0.001) compared with controls. However, three studies showed that resistance training in middle-aged subjects (n=78) was not associated with changes in arterial stiffness. In addition, although high-intensity resistance training (n=87) was significantly associated with an increase in stiffness of 11.6%, moderate-intensity resistance training (n=106) showed no such association. Conclusion High-intensity resistance training is associated with increased arterial stiffness in young subjects with low baseline levels of arterial stiffness.