Effects of exercise training on arterial function in type 2 diabetes mellitus: A systematic review and meta-analysis

Abstract

Background and Objective: Controversy exists among trials assessing whether exercise can improve arterial function in type 2 diabetes mellitus (T2DM) subjects. Therefore the aim of this study was to systematically review and quantify the effects of exercise on arterial function in T2DM subjects. Methods: MEDLINE, Cochrane, Scopus and Web of Science were searched up until January 2013 for randomized controlled trials evaluating the effects of exercise interventions lasting 4 weeks or more on arterial function in T2DM subjects. Flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) of the brachial conduit artery were considered for assessment of arterial endothelial function and smooth muscle function, respectively. Results: Five randomized trials comparing exercise and control groups (overall n = 217) met the inclusion criteria. The mean exercise characteristics were as follows: 3.6 sessions per week, 67.5 min per session, intensity at 74.4 % of the maximum heart rate (HRmax), for 14 weeks. The post-intervention mean difference in FMD favoured the exercise groups over the control groups (2.23 %; P < 0.0001). No significant post-intervention mean difference in NMD (1.22 %; P = 0.29) was found between the groups. Neither heterogeneity nor publication bias was detected among the trials. Conclusion: Exercise training alone improved FMD, showing its capacity to restore arterial endothelial function in T2DM subjects. However, further research is needed to determine whether longer and/or more intense exercise interventions could enhance arterial smooth muscle function in this population. © 2013 Springer International Publishing Switzerland.