Effect of a 12-Week Structured Yoga Program Added to Standard Care on Glycemic Control and Heart Rate Variability in Adults With Type 2 Diabetes Mellitus: A Randomized Controlled Trial

Objectives: To evaluate the effect of a structured 12-week yoga program added to standard medical care on glycemic control and selected heart rate variability (HRV) parameters in adults with type 2 diabetes mellitus (T2DM). Methods: This parallel-group randomized controlled trial included 160 adults aged 35–65 years with T2DM, randomly allocated to yoga plus standard care (n=80) or standard care alone (n=80). The intervention consisted of supervised 60-min yoga sessions, 5 days weekly for 12 weeks. Fasting blood sugar (FBS), postprandial blood sugar (PPBS), glycated hemoglobin (HbA1c), and HRV parameters were assessed at baseline and after 12 weeks. Between-group differences were evaluated using independent-samples t-tests, with mean differences and 95% confidence intervals (CIs). Results: At 12 weeks, the yoga group demonstrated significantly lower FBS (92.3±10.9 vs. 118.1±8.68 mg/dL; mean difference −25.8, 95% CI −28.9–−22.7), PPBS (142.8±10.3 vs. 165.8±8.08 mg/dL; mean difference −23.0, 95% CI −25.9–−20.1), and HbA1c (5.59±0.59% vs. 6.50±0.52%; mean difference −0.91 percentage points, 95% CI −1.08–−0.74); all p<0.001. Higher high-frequency power, standard deviation of normal-to-normal intervals, root mean square of successive differences, percentage of successive normal-to-normal intervals differing by more than 50 ms, and number of successive interval pairs differing by more than 50 ms values were observed in the yoga group. Conclusion: A structured 12-week yoga program added to standard care was associated with improved glycemic parameters in adults with T2DM. Differences in selected HRV indices were also observed, although methodological limitations restricted their physiological interpretation. Further randomized trials incorporating standardized HRV assessment, medication monitoring, intervention adherence, and safety evaluation are warranted