Effects of Autonomic Modulation on Myofascial Pain and Heart Rate Variability in Post-stroke Individuals

Stroke is a leading cause of chronic disability, frequently accompanied by Myofascial Pain Syndrome (MPS) and Autonomic Nervous System (ANS) dysregulation. Autonomic modulation, including slow diaphragmatic breathing, Heart Rate Variability (HRV) biofeedback and mindfulness-based relaxation, offers a non-pharmacological approach targeting both musculoskeletal and autonomic impairments simultaneously. A randomized controlled trial was conducted on 40 chronic post-stroke individuals (≥ 6 months post-stroke), randomly allocated into an Autonomic Modulation Group (AMG, n = 20) and a Control Group (CG, n = 20) receiving conventional physiotherapy. Both groups underwent 4 weeks of intervention (35 minutes per session, 5 days per week). Primary outcomes included pain intensity (Visual Analogue Scale [VAS]), pressure pain threshold (PPT via algometry) and HRV indices (root mean square of successive differences [RMSSD], high-frequency power [HF] and LF/HF ratio), measured at baseline and after 4 weeks. The AMG demonstrated significantly greater improvements in VAS (mean change: 3.3 ± 0.8 vs. 1.2 ± 0.6; P < 0.001), PPT (0.7 ± 0.3 vs. 0.2 ± 0.2 kg/cm²; P < 0.001), RMSSD (11.4 ± 4.0 vs. 1.5 ± 2.5 ms; P < 0.001), HF power (130 ± 40 vs. 15 ± 30 ms²; P < 0.001) and a greater reduction in LF/HF ratio (1.2 ± 0.4 vs. 0.3 ± 0.3; P < 0.001) compared to the CG. Autonomic modulation significantly reduces myofascial pain and restores autonomic balance in post-stroke individuals, supporting its integration as an adjunct in neurorehabilitation.