The Effect of Exercise on Vascular Function and Stiffness in Type 2 Diabetes: A Systematic Review and Meta-analysis.

Deterioration of the structure and function of the vascular system is the underlying feature in cardiovascular disease (CVD), which is the highest cause of mortality in type 2 diabetes (T2D). Studies assessing the effect of exercise on vascular function and stiffness have used different measurement techniques and small cohorts, making it difficult to conclude on the overall efficacy of exercise on these outcomes. The aim of this study was to assess the effect of exercise on vascular function and stiffness in T2D. Electronic database searches were performed in AMED, MEDLINE, MEDLINE Daily Update, PREMEDLINE, SPORTDiscus, CINAHL, EMBASE and Web of Science. The effect size (ES), and 95% confidence intervals (CIs) of eligible studies were calculated. Pooled estimates of the effect of aerobic exercise (AEx) on vascular function and stiffness, using ES, were obtained. Results show that AEx led to a near-significant reduction in PWV (ES = -0.472; 95% CI: -0.949 to 0.005; P = 0.052), a significant reduction in EID (ES = 0.416, 95% CI: 0.062 to 0.769; P= 0.021), and a non-significant benefit in FMD measures. There were limited studies using resistance training or in combination with aerobic exercise, to assess a pooled effect on vascular function or stiffness. These data suggest that aerobic exercise training should be used as a primary treatment strategy for improving vascular smooth muscle function as measured by EID in individuals with T2D. There is currently insufficient evidence concerning the efficacy of regular exercise for improving vascular function and stiffness as measured by FMD and PWV.