Effects of Resistance Training on Arterial Stiffness in Persons at Risk for Cardiovascular Disease: A Meta-analysis.

BACKGROUND: Arterial stiffness (AS) is a key measure in predicting risk for cardiovascular disease (CVD) and related events, independent of other risk factors. Resistance training (RT) has been shown to increase AS in young healthy subjects. However, the effects of RT on AS in persons with or at risk for CVD remain unclear; this uncertainty is a barrier to RT prescription in this population. Considering RT may be as effective as or superior to aerobic exercise prescription in treating some co-morbidities associated with CVD, it would be helpful to clarify whether RT does lead to clinically meaningful increases (detrimental) in AS in those with CVD or CVD risk factors.

OBJECTIVES: The aim of this study was to (1) assess the effects of RT on measures of AS in at-risk populations, and (2) discuss the implications of the findings for clinical exercise physiologists.

DATA SOURCES: The electronic databases PubMed, Web of Science, SPORTDiscus, and Google Scholar were searched from inception to February 2018. The reference lists of eligible articles and reviews were also checked.

STUDY SELECTION: Inclusion criteria were: (1) the trial was a randomized controlled trial; (2) exercise prescription of RT or a combination of resistance and aerobic exercise for at least 8 weeks; (3) control group characteristics allowed for comparison of the main effects of the exercise prescription; (4) subjects had known CVD or a risk factor associated with CVD according to the American College of Sports Medicine (ACSM) guidelines; (5) article measured at least carotid to femoral pulse wave velocity (PWV) or augmentation index (AIx).

APPRAISAL AND SYNTHESIS METHODS: Initially, 1427 articles were identified. After evaluation of study characteristics, quality and validity data from 12 articles and 13 cohorts involving 651 participants (223 women, 338 men, 90 unknown) were extracted for the meta-analysis. To enable comparisons between assessments, and to infer clinical significance, standardized mean differences (SMD) were calculated. When data were not available, values were estimated according to Cochrane guidelines.

RESULTS: According to the JADAD scale, the mean quality of studies was 3 out of 5. The duration of the included studies ranged from 8 weeks to 24 months. RT trended towards decreasing (improving) PWV (SMD = - 0.168, 95% CI - 0.854 to 0.152, p = 0.057). There were no significant differences in AIx (SMD = - 0.286), diastolic blood pressure (SMD = - 0.147), systolic blood pressure (SMD = - 0.126), or central systolic blood pressure (SMD = - 0.405).

CONCLUSION: The available evidence suggests that RT does not increase (worsen) AS in patients who have or are at risk for CVD. Considering RT may be as effective as or superior to aerobic exercise prescription in treating some co-morbidities associated with CVD, these findings suggest that RT is a suitable exercise prescription in primary and secondary prevention settings.