How Heart Rate Variability Biofeedback May Relieve Jaw Pain and Bruxism

A new case study published by David Cheng (2025) in the Journal of the California Dental Association presents promising evidence for the use of heart rate variability biofeedback (HRV-B) and resonance frequency breathing (RFB) in managing temporomandibular dysfunction (TMD) and sleep bruxism (SB). These conditions, often treated with oral orthotic occlusal devices (OOOD), can be driven by deeper physiological mechanisms such as autonomic dysregulation and dysfunctional breathing—factors that mechanical devices alone cannot address.

This article explores a compelling alternative: training the body to self-regulate through biofeedback. Biofeedback is a technique where individuals gain voluntary control over physiological processes, such as heart rate or breathing, by receiving real-time feedback. HRV biofeedback, in particular, targets the autonomic nervous system to restore balance between sympathetic and parasympathetic activity. By helping patients reach their resonance frequency (around 6 breaths per minute), HRV-B can enhance vagal tone, emotional regulation, and overall physiological coherence.

In the context of dentistry, where chronic jaw tension, grinding, and stress-related muscle hyperactivity are common, the application of HRV-B represents an important paradigm shift: treating the nervous system rather than merely the bite. This case report highlights how one patient achieved not only symptom remission but also measurable physiological improvements—an inspiring intersection of neuroscience, psychology, and dental care.

Methods

The case involved a 34-year-old male with a 20-year history of chronic headaches, jaw pain, and sleep bruxism. The patient also experienced frequent nighttime awakenings and anxiety, reflected in a Beck Anxiety Inventory (BAI) score of 16 (moderate anxiety). Due to hypersensitivity to foreign objects, he declined oral orthotic therapy, opting instead for HRV-B and breathing retraining.

Assessment Tools and Devices:

• Capnotrainer (Better Physiology, USA) for monitoring end-tidal CO₂ (PetCO₂) and HRV via photoplethysmography (PPG).

• PetCO₂ values under 35 mmHg indicated hypocapnia (over-breathing), associated with reduced cerebral blood flow, anxiety, and muscle tension.

Training Structure:

• Two-phase educational model: first focused on breath awareness, diaphragmatic control, and nasal inhalation; second on guided resonance frequency breathing (~5 breaths/min) once PetCO₂ reached eucapnia levels (35–45 mmHg).

• Training employed both classical and operant conditioning, rewarding stable breathing and physiological coherence.

Session Frequency and Progression:

• Eight sessions over approximately three months.

• Each session involved continuous monitoring of HRV and CO₂, with feedback adjusted in real time.

This structured, feedback-based approach allowed the patient to visualize physiological changes and develop self-regulation skills—a hallmark of biofeedback efficacy.

Results

Initial data revealed significant autonomic and respiratory dysregulation:

• PetCO₂ ranged between 18–34 mmHg (indicative of chronic hypocapnia).

• Heart rate fluctuated between 60–94 bpm, showing incoherent HRV patterns.

• Breathing style: rapid, shallow, and mouth-based, all linked to sympathetic overactivity.

By the eighth session, clear physiological and symptomatic changes emerged:

• PetCO₂ normalized to >35 mmHg.

• HRV showed coherent, low-frequency dominance, indicating parasympathetic restoration.

• BAI score dropped from 16 to 5, signaling a reduction from moderate to minimal anxiety.

• Patient reported complete resolution of jaw pain, headaches, bruxism, and nocturnal awakenings.

These outcomes align with broader literature showing HRV-B’s efficacy in reducing anxiety, pain, and autonomic hyperarousal (Goessl et al., 2017; Lehrer & Woolfolk, 2021).

Discussion

This case bridges two traditionally separate domains: dentistry and psychophysiology. While occlusal devices focus on mechanical protection, HRV biofeedback addresses the physiological root cause —autonomic imbalance driven by stress and dysfunctional breathing.

Research consistently links sympathetic dominance to TMD and bruxism. Elevated cortisol, heightened HPA-axis activity, and altered HRV patterns reflect how stress translates into muscular and behavioral tension. In this context, HRV-B offers a way to retrain not just the jaw muscles, but the entire stress response system.

For clinical practice, this case suggests a multi-tiered approach:

1. For clients: HRV-B empowers self-regulation, offering a non-invasive pathway to symptom relief.

2. For clinicians: It integrates easily with existing care models, enhancing outcomes for patients resistant to or unable to tolerate oral devices.

3. For neurofeedback practitioners: HRV data can complement EEG measures, creating multimodal protocols where autonomic and cortical regulation are trained in tandem.

Moreover, the study reinforces the importance of individualized breathing retraining. Restoring eucapnia before RFB is critical; starting RFB too early can exacerbate hypocapnia and stress. This case also illustrates how patient readiness, psychological engagement, and feedback awareness shape biofeedback success.

Brendan's Perspective

When I read Cheng’s case, I couldn’t help but think about how often we overlook the jaw as a mirror of the nervous system. Tension held in the masticatory muscles is often a downstream effect of chronic sympathetic activation. Many clients with TMD or bruxism present with EEG patterns that echo this imbalance—high beta activity, often in the central and frontal regions, reflecting hypervigilance and cognitive overdrive.

In clinical neurofeedback, I frequently pair HRV training with EEG-based SMR (12–15 Hz) or alpha-up protocols to reinforce calm yet alert states. The combination can be transformative. HRV training stabilizes the autonomic system, while neurofeedback fine-tunes cortical inhibition. This dual approach helps clients transition from reactivity to regulation.

I also appreciate Cheng’s emphasis on hypocapnia correction before introducing resonance breathing—a nuance often missed in generalized breathwork. CO₂ is not just a waste gas; it’s a messenger for vascular tone and oxygen delivery. As clinicians, we should think of it as the brain’s thermostat. If it runs too low, everything tightens—including thought, muscle, and mood.

Integrating HRV-B into neurofeedback practice doesn’t mean abandoning EEG; it means expanding our toolkit. For clients with TMD, chronic pain, or anxiety-linked muscle tension, pairing HRV coherence training with alpha-SMR balance can accelerate recovery and deepen resilience.

Conclusion

This case report opens a valuable door for interdisciplinary care. By addressing the autonomic and respiratory dimensionsof TMD and bruxism, HRV biofeedback provides a scientifically grounded, patient-centered alternative to mechanical interventions. For clinicians and practitioners alike, it exemplifies how precision in breath and feedback can translate into profound systemic change.

As we continue bridging neuroscience and dentistry, one truth becomes clear: when we train the breath, we train the brain—and often, the body follows.

Reference

Cheng, D. (2025). Heart Rate Variability Biofeedback in the Management of TMD and Bruxism: Case Report. Journal of the California Dental Association, 53(1), 2565337. https://doi.org/10.1080/19424396.2025.2565337