Effects of Yoga-Based Intervention with Bhramari Pranayama and Chakra Meditation on Sympatho-Vagal Balance in Perimenopausal Women: A Randomized Controlled Trial

Purpose. Perimenopause is associated with progressive altered autonomic regulation manifesting as sympathetic hyperactivation and impaired parasympathetic modulation, increasing cardiovascular and psychological vulnerability. Heart rate variability (HRV) provides a validated, non-invasive index of cardiac autonomic regulation. Yoga-based interventions incorporating controlled breathing and meditation may favorably modulate sympatho-vagal balance, yet robust randomized controlled trial (RCT) evidence in perimenopausal women specifically examining assessment of selected HRV indices is lacking. Objective: to evaluate the effect of an eight-week structured yoga intervention combining Bhramari pranayama and chakra meditation on HRV time-domain parameters (RMSSD, pNN50, heart rate) and frequency-domain parameters (LF power, HF power, LF/HF ratio) in peri-menopausal women. Materials & Methods. Parallel-group, single-blind RCT. Sixty perimenopausal women (40–55 years) were randomized (1:1) to a yoga intervention group (n=30) or a waitlist-control group (n=30). The yoga group received 60-minute supervised sessions five days/week for eight weeks, incorporating Bhramari pranayama (20 min) and chakra meditation (20 min). Short-term HRV (5 min, supine) was recorded using a validated ECG-based system and analyzed per Task Force (ESC/NASPE 1996) standards. Primary outcomes: RMSSD, pNN50, LF/HF ratio. Secondary outcomes: heart rate, systolic blood pressure, LF power, HF power. Between-group changes were compared by ANCOVA (baseline-adjusted). Effect size: Cohen's d. Results. Fifty-six participants completed the trial (28 per group; retention: 93.3%). Yoga group demonstrated significant post-intervention improvements vs. controls: RMSSD (34.7±7.1 vs. 23.4±6.0 ms; Δ=+12.3 ms, 95%CI: 9.1–14.5, p<0.001, d=1.89); pNN50 (18.6±4.9 vs. 9.1±3.5%; Δ=+10.4%, p<0.001, d=2.50); HF power (+113.8 ms², p<0.001, d=1.74); LF/HF ratio (2.1±0.8 vs. 3.7±1.1; Δ=−1.7, p<0.001, d=1.63); LF power decreased (−93.8 ms², p<0.001); heart rate decreased (74.5±6.4 vs. 82.1±7.8 bpm, p<0.001); systolic BP reduced (119.8±8.7 vs. 128.1±10.0 mmHg, p=0.001). All effect sizes were large (d=1.07–2.50). No adverse events were recorded. Conclusions. Eight weeks of yoga combining Bhramari pranayama and chakra meditation produced large-magnitude improvements across all HRV time-domain and frequency-domain parameters in peri-menopausal women, indicating a clinically meaningful restoration of sympatho-vagal balance. These findings support yoga as an evidence-based, non-pharmacological autonomic intervention in peri-menopausal care.