Comparing Aerobic Interval Training with Other Forms of Physical Exercise for Brachial Artery Endothelial Function Improvement: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Background Brachial artery endothelial function, measured by the flow-mediated dilatation (FMD) technique, serves as a surrogate for coronary endothelial function and is recognized as an independent predictor of cardiovascular disease risk. Despite the known benefits of physical exercise interventions (PEI) in improving endothelial function, limited evidence exists to guide practitioners on the most effective form of PEI for enhancing endothelial function. The aim of this article is to investigate the effects of different PEI modalities on brachial artery FMD, and to establish the most effective PEI through a systematic review and network meta-analysis (NMA). Methods PubMed, WoS, CINAHL, EMBASE, CENTRAL and EBSCOhost was conducted from inception to February 20th, 2025. Randomized controlled studies investigating the effects of PEI on brachial artery FMD in adults were included. Both pairwise and Bayesian NMA were conducted using random-effects model to compare different PEI modalities within primary (aerobic training, resistance training and combined training) and secondary (continuous aerobic training vs. interval aerobic training vs. dynamic resistance training vs. combined training) categorizations. The PEI effectiveness was ranked using the surface under the cumulative ranking curve (SUCRA). RESULTS In total, 78 studies with 3554 participants (43% females, 51.9 ± 15.1 years of age) were included in the analysis. A summarized evidence of 119 effect sizes through pairwise comparisons showed improvement in FMD (mean difference [MD], 2.24%; 95% confidence interval [CI], 1.90 to 2.58, p < 0.001) following different PEI, without difference between magnitude of the effect between healthy and asymptomatic individuals (Q, 1.27, p = 0.260). As shown in the NMA, the rank order within a primary classification showed aerobic training as the most effective (SUCRA: 89.8%, MD, 2.37%, 95% credible interval [CrI], 1.95 to 2.80) followed by resistance training (SUCRA: 66.0%, MD, 2.07%, 95% CrI, 1.34 to 2.79), and combined (aerobic and resistance) training (SUCRA: 44.1%, MD, 1.67%, 95% CrI, 0.73 to 2.6). Secondary NMA identified interval aerobic training as the most effective (SUCRA: 99.1%, MD, 3.07%, 95% CrI, 1.37 to 3.76), which showed to be more effective than CAT (MD, 1.08%), DRT (MD, 1.04%), and CT (MD, 1.36%). Moreover, a negative association was found between FMD improvement and both intervention duration and overall training load, while positive associations were observed with weekly training frequency, single session duration, and weekly training duration. CONCLUSIONS Various PEI modalities have demonstrated effectiveness in improving brachial artery FMD, with interval aerobic exercises of higher intensities emerging as the most effective, followed by dynamic resistance training, continuous aerobic training and combined training. These findings have significant implications for informing future exercise guidelines aimed at both prevention and treatment of endothelial dysfunction.