Impact of metabolic and bariatric surgery on heart rate variability: a systematic review and meta-analysis

Obesity is associated with autonomic nervous system (ANS) dysfunction, characterized by increased sympathetic activity, and reduced parasympathetic tone, which together contribute to elevated cardiovascular risk. Heart rate variability (HRV), a key marker of ANS function, is often reduced in individuals with obesity. Metabolic and bariatric surgery (MBS) is an effective intervention for severe obesity; however, its impact on HRV remains unclear. A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Literature searches were performed in PubMed, Scopus, Embase, Google Scholar, and Web of Science. Studies evaluating HRV before and after MBS were included. Meta-analysis was carried out using Comprehensive Meta-Analysis (CMA) version 4 software. Eleven studies comprising 322 patients were included. MBS significantly improved HRV (weighted mean difference: 12.011; 95% CI: 6.984-17.038; p < 0.001). Meta-regression demonstrated a positive correlation between BMI reduction and HRV improvement (slope: 1.553; 95% CI: 0.203-2.903; p = 0.024). HRV improvements were observed at both short-term (< 6 months) and long-term (≥ 6 months) follow-up. Roux-en-Y gastric bypass (RYGB) produced greater HRV improvements compared with sleeve gastrectomy (SG). MBS significantly enhances HRV, suggesting partial reversal of obesity-related ANS dysfunction. The observed association between weight loss and HRV improvement highlights MBS as a promising cardiometabolic intervention.