Exercise training and endothelial function in patients with type 2 diabetes: a meta-analysis

Shanhu Qiu, Xue Cai, Han Yin, Zilin Sun, Martina Zügel, Jürgen Michael Steinacker, Uwe Schumann

Exercise training is considered a cornerstone in the management of type 2 diabetes, which is associated with impaired endothelial function. However, the association of exercise training with endothelial function in type 2 diabetes patients has not been fully understood. This meta-analysis aimed to investigate their associations with focus on exercise types. Databases were searched up to January 2018 for studies evaluating the influences of exercise training with durations ≥ 8 weeks on endothelial function assessed by flow-mediated dilation (FMD) among type 2 diabetes patients or between type 2 diabetics and non-diabetics. Data were pooled using random-effects models to obtain the weighted mean differences (WMDs) and 95% confidence intervals (CIs). Sixteen databases were included. Exercise training resulted in an overall improvement in FMD by 1.77% (95% CI 0.94-2.59%) in type 2 diabetes patients. Specifically, both aerobic and combined aerobic and resistance exercise increased FMD by 1.21% (95% CI 0.23-2.19%) and 2.49% (95% CI 1.17-3.81%), respectively; but resistance exercise only showed a trend. High-intensity interval aerobic exercise did not significantly improve FMD over moderate-intensity continuous exercise. Notably, the improvement in FMD among type 2 diabetes patients was smaller compared with non-diabetics in response to exercise training (WMD - 0.72%, 95% CI - 1.36 to - 0.08%) or specifically to aerobic exercise (WMD - 0.65%, 95% CI - 1.31 to 0.01%). Exercise training, in particular aerobic and combined exercise, improves endothelial function in type 2 diabetes patients, but such an improvement appears to be weakened compared with non-diabetics. Trial registration PROSPERO CRD42018087376.