Find the article here: https://jamanetwork.com/journals/jamapsychiatry/article-abstract/2839605

In this insightful episode of The Heart Rate Variability Podcast, host Matt Bennett sits down with Dr. David Eddie, a clinical psychologist and researcher at Massachusetts General Hospital and Assistant Professor at Harvard Medical School. Together, they explore how Heart Rate Variability (HRV) is transforming the landscape of addiction recovery, psychotherapy, and digital mental health.

Dr. Eddie shares how HRV can serve as both a biomarker for relapse risk and a tool for emotional regulation, shedding light on how AI, wearable technology, and stress-detection algorithms could revolutionize real-time intervention in substance use treatment.

Listeners will gain a deeper understanding of how HRV biofeedback, digital monitoring, and personalized algorithms can support clients in recovery, enhance self-awareness, and inform clinicians’ decision-making in psychotherapy.

How Dr. David Eddie began his HRV journey during graduate research at Rutgers and the Recovery Research Institute.

HRV as a biomarker for pathology and relapse risk in substance use disorder and mental health conditions.

Developing stress-detection algorithms that leverage real-time HRV data through wearables and AI.

Challenges of variability and individual differences in HRV data across populations.

Integrating ecological momentary assessment (EMA) and ambulatory psychophysiological monitoring for clinical insights.

How HRV biofeedback supports recovery and emotional regulation in psychotherapy and addiction treatment.

Ethical and practical issues around proprietary algorithms, data transparency, and commercial wearables.

The future of HRV research, AI integration, and passive monitoring in clinical psychology.

HRV is both a symptom and contributor to addiction and mental health challenges, offering potential for early detection of relapse risk.

Wearables and AI can help clinicians intervene in real time — possibly preventing relapse or emotional crises before they occur.

Personalized baselines and individual calibration are essential to improve algorithm accuracy for diverse populations.

HRV biofeedback provides an accessible, evidence-based method to help clients build resilience, reduce craving, and regulate their nervous system.

Future advances will make passive, scalable HRV monitoring a core element of digital mental health and recovery care.

Dr. David Eddie is a clinical psychologist and researcher at Massachusetts General Hospital’s Recovery Research Institute and the Center for Digital Mental Health, as well as an Assistant Professor of Psychiatry at Harvard Medical School. His work focuses on addiction recovery, psychophysiology, and integrating HRV into digital and clinical interventions.

Follow his work at Recovery Research Institute or through Harvard Medical School publications.

Resource 1:

Title: Associations between mental health disorder symptoms and cardiac function among Royal Canadian Mounted police cadets during the Cadet training program

Authors: R.N. Carleton, T.A. Teckchandani, J.P. Neary, J.E. Samayoa, J.M.B. Khoury, K.Q. Maguire, G.P. Krätzig, & G.J.G. Asmundson

Publication: Journal of Psychiatric Research

Link: https://www.sciencedirect.com/science/article/pii/S0022395625006521

Resource 2:

Title: Transgenerational effects of violence in adolescents exposed to grandmaternal intimate partner violence during pregnancy: Heart rate variability and DNA methylation

Authors: Nayara Cristina dos Santos Oliveira, Aline Furtado Bastos, Fernanda Serpeloni, & Simone Gonçalves de Assis

Publication: Behavioural Brain Research

Link: https://www.sciencedirect.com/science/article/abs/pii/S0166432825004735

Resource 3:

Title: The role of separation anxiety and autonomic dysregulation in pediatric vasovagal syncope. A cross-sectional study

Authors: Gaia Cuzzocrea, Andrea Fontana, Cristiana Alessia Guido, Marta Mascanzoni, Alberto Spalice, Camilla Guccione, Angelos Halaris, Stephen Porges, Lucia Sideli, & Vincenzo Caretti

Publication: Journal of Psychiatric Research

Link: https://www.sciencedirect.com/science/article/abs/pii/S0022395625006351

Resource 4:

Title: Acute cardiovascular and cerebral blood flow responses to high-frequency, low-amplitude vibration on the neck

Authors: Viet Q Dinh, Malinda Hansen, K Austin Davis, Lindsey Peralez, & Caroline A Rickards

Publication: Journal of Applied Physiology (via PMC)

Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12551627/

Resource 5:

Title: Autonomic Flexibility and Early Treatment Success: Heart Rate Variability Predicts Remission in First-Episode Psychosis

Authors: Judith Rohde, Samantha Weber, Mateo de Bardeci, Aygün Ertuğrul, Grammato Amexi, Eva Schultz, & Sebastian Olbrich

Publication: Schizophrenia Bulletin

Link: https://academic.oup.com/schizophreniabulletin/advance-article/doi/10.1093/schbul/sbaf191/8305265?login=false

Resource 6:

Title: Interplay between key metabolic hormones, metabolic factors, renal function, and heart rate variability in humans with obesity

Authors: Kitchaya Pongwattanapakin, Chit Care, Chantacha Sitticharoon, Kittikorn Tommy Wilasrusmee, Issarawan Keadkraichaiwat, Pailin Maikaew, & Rungnapa Sririwichitchai

Publication: Scientific Reports

Link: https://www.nature.com/articles/s41598-025-21757-1

Resource 7:

Title: Metabolic Minute – Heart Rate Variability

Authors: WCCB Web Staff (featuring Dr. Gary Rolband, Stephen Gage, and Matt Bennett)

Publication: WCCB Charlotte

Link: https://www.wccbcharlotte.com/2025/10/27/metabolic-minute-heart-rate-variability/

Show Notes

Resource 1:

Title: Top 50 scariest movies of 2025 (and Fright Night Physiology)

Publication: WISN.com / Science of Scare Project

Link: https://www.wisn.com/article/top-50-scariest-movies-2025/69140286

Resource 2:

Title: Heart Rate Variability as a Key to Regulation and Stress

Author: D. N. Solomon

Publication: Psychology Today

Link: https://www.psychologytoday.com/us/blog/the-narrative-nurse-practitioner/202412/heart-rate-variability-as-a-key-to-regulation-and

Resource 3:

Title: Haunted House, Healthy Heart

Publication: Business Health Trust

Link: https://businesshealthtrust.com/news_insights/haunted-house-healthy-heart/

Resource 4:

Title: Why Do We Love Being Scared? The Science Behind Horror Movies

Author: A. Bennett

Publication: Promega Connections

Link: https://www.promegaconnections.com/the-science-behind-horror-movies/

Resource 5:

Title: Playing With Fear: A Field Study in Recreational Horror

Authors: M. M. Andersen, A. Coltan, et al.

Publication: PMC (via Emotion)

Link: httpss://pmc.ncbi.nlm.nih.gov/articles/PMC7734554/

Resource 6:

Title: Scared together: Heart rate synchrony and social closeness in a high-intensity horror setting

Authors: M. M. Andersen, et al.

Publication: PubMed (via Psychological Science)

Link: https://pubmed.ncbi.nlm.nih.gov/40720311/

Resource 7:

Title: I tracked my heart rate through the 10 haunted houses of Halloween Horror Nights...

Author: K. Weekman

Publication: Yahoo.com

Link: https://www.yahoo.com/entertainment/article/i-tracked-my-heart-rate-through-the-10-haunted-houses-of-halloween-horror-nights-heres-what-scared-me-most-180025551.html

Show Notes

Resource 1:

Title: Pleasant odors specifically promote a soothing autonomic response and brain–body coupling through respiratory modulation

Authors: Valentin Ghibaudo, Matthias Turrel, Jules Granget, Maëlys Souilhol, Samuel Garcia, Jane Plailly & Nathalie Buonviso

Publication: Scientific Reports

Link: https://www.nature.com/articles/s41598-025-20422-x

Resource 2:

Title: Improved non-invasive detection of sleep stages when combining skin sympathetic nerve activity and heart rate variability analysis with AI

Authors: Md. Aktaruzzaman & Thomas H. Everett IV

Publication: Scientific Reports

Link: https://www.nature.com/articles/s41598-025-20282-5

Resource 3:

Title: Increased sleep apnea-specific hypoxic burden is independently associated with cardiovascular autonomic dysfunction in obstructive sleep apnea: A large-scale study

Authors: Chenyang Li, Zhenger Zhou, Xiaozhen Zhang, Enhui Zhou, Tianjiao Zhou, Jingyu Zhang, Xinyi Li, Jianyin Zou, Huajun Xu, Jian Guan, Yupu Liu, Suru Liu, Xiaoyue Zhu, Weijun Huang, Hongliang Yi, Shankai Yin

Publication: Sleep Medicine

Link: https://www.sciencedirect.com/science/article/abs/pii/S1389945725005386

Resource 4:

Title: Strengthening the heart by means of a gratitude intervention?

Authors: Andreas R. Schwerdtfeger, Claudia Traunmüller, Bernhard Weber & Christian Rominger

Publication: The Journal of Positive Psychology

Link: https://www.tandfonline.com/doi/full/10.1080/17439760.2025.2574048?af=R#abstract

Resource 5:

Title: Child and marital stress are associated with a psychophysiological index of self-regulatory capacities among parents of preschool children

Authors: Sasha MacNeil, Chelsea da Estrela, Warren Caldwell, Jean-Philippe Gouin

Publication: International Journal of Psychophysiology

Link: https://www.sciencedirect.com/science/article/pii/S0167876025007470?via%3Dihub

Resource 6:

Title: Factors influencing heart rate variability in nurses following night shifts: a prospective observational clinical study

Authors: Taihe Zhan, Ziying Zhang, Zhimin Shi, Hongyan Xie, Daogang Zha & Xiumei Wei

Publication: BMC Nursing

Link: httpsD://bmcnurs.biomedcentral.com/articles/10.1186/s12912-025-03975-0

Resource 7:

Title: Heart Rate Variability Biofeedback and Mental Stress Myocardial Flow Reserve: A Randomized Clinical Trial

Authors: Amit J. Shah, Paolo Raggi, Hua She, et al.

Publication: JAMA Network Open

Link: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2840378

Resource 8:

Title: VCU research in action: Teaching patients to take a deep breath

Author: Olivia Trani

Publication: VCU News

Link: https://news.vcu.edu/article/2025/10/vcu-research-in-action-teaching-patients-to-take-a-deep-breath

In this solo episode of the Heart Rate Variability Podcast, Matt Bennett explores the science and practicality of resonance frequency breathing, a term he notices is often misused. He introduces his AI counterpart, AI Matt, to present the research on resonance frequency breathing, which involves finding a natural rhythm for breathing that aligns with the body's optimal pace. Matt aims to delve into the correct usage of this term, discuss its scientific basis, and share practical applications in the episode.

Matt discussed resonance frequency breathing, explaining that while 6 breaths per minute is often cited, the actual rate can vary based on factors like height. He noted that trained biofeedback practitioners have observed rates as low as 3.5 breaths per minute in special operators and professional athletes. Matt emphasized the importance of synchronization between the heart, breath, and nervous system, as well as the impact on brain functioning.

Matt discussed the concept of resonance frequency breathing, noting that while research suggests an average of 6 breaths per minute, individual rates can vary widely. He explained that resonance frequency assessments involve gradually reducing breathing rate from 7 to 3.5 breaths per minute to find the rate that maximizes HRV. Matt emphasized that while height may influence resonance frequency, factors like fitness and body mass could also affect it, particularly for former athletes. He recommended practicing paced breathing before taking the assessment and suggested that repeated testing might show small changes in breathing rate over time.

Matt discussed the importance of regularly reassessing one's resonance frequency breathing to ensure accuracy, especially if consistent readings are obtained over several months without significant lifestyle changes. He shared his personal experience with adjusting his breathing patterns, including experimenting with a 4.5 to 3.5 breaths per minute rate and a 2:1 inhale-to-exhale ratio, inspired by recent research suggesting extended exhales can improve low-frequency heart rate variability. Matt emphasized the significance of personalized assessments using tools like the OptimalHRV app to determine optimal breathing patterns and encouraged others to explore different breathing techniques for maximum impact.

Matt discussed the importance of practicing residence frequency breathing assessment and emphasized the value of this technique in maximizing breathwork practices. He noted that while the concept is gaining recognition among fitness influencers and in peer-reviewed research, the full impact of the science is often overlooked in blog posts. Matt planned to include relevant research in the show notes and promised to cover this topic further in the next episode.

Resource 1:

Title: The relationship between heart rate variability and affective disorders: associations with symptomatic improvement and therapeutic alliance

Authors: Alexandra F. Gonçalves, Eugénia Ribeiro, Adriana Sampaio, Natividade S. Couto-Pereira, Pedro Moreira & Joana F. Coutinho

Publication: BMC Psychology

Link: https://bmcpsychology.biomedcentral.com/articles/10.1186/s40359-025-02960-1

Resource 2:

Title: Development and validation of the socio-evaluative N-back task to investigate the impact of acute social stress on working memory

Authors: Matthias Haucke, Sabrina Golde & Stephan Heinzel

Publication: Scientific Reports

Link: https://www.nature.com/articles/s41598-025-22611-0

Resource 3:

Title: Panic Attack Prediction for Patients With Panic Disorder via Machine Learning and Wearable Electrocardiography Monitoring: Model Development and Validation Study

Authors: Hayoung Oh, Hunmin Do, Chaehyun Maeng, Jinsuk Park, Taejun Yoon, Jihwan Kim, Hyeran Hwang, Seoin Choi, & Piao Huilin

Publication: Journal of Medical Internet Research

Link: https://www.jmir.org/2025/1/e69045

Resource 4:

Title: Non-invasive cardiovascular risk stratification in type 2 diabetes: a pulse wave and pulse rate variability analysis with machine learning

Authors: Saurav Kumar, Apakrita Tayade, Amber Shrivastava, & Ravi Bhallamudi

Publication: Biomedical Signal Processing and Control (via Science Direct)

Link: https://www.sciencedirect.com/science/article/abs/pii/S1746809425014491

Resource 5:

Title: How Tracking Your Health Metrics Can Help You Live Longer

Author: Alice Park (Interview with Zahi Fayad)

Publication: TIME

Link: https://time.com/7324741/health-metrics-tracking-live-longer/

Resource 6:

Title: Stressed at Work? Your Heart Disease Risk Just Jumped 50%. Here’s the One Number That Shows How to Fight Back

Author: Julien Raby

Publication: BoxLife Magazine

Link: https://boxlifemagazine.com/boost-heart-resilience-by-tracking-hrv/

Resource 7:

Title: “Resonance Breathing” Is The Anti-Stress Hack You Can Do Anywhere

Author: Carolyn Steber

Publication: Bustle

Link: https://www.bustle.com/wellness/resonance-frequency-breathing-stress-hack

Below are the links to the studies and articles discussed in this episode:

In this episode of the Heart Rate Variability Podcast, host Matt Bennett sits down once again with Dr. Inna Khazan, a leading expert in HRV biofeedback and applied psychophysiology. Together, they unpack one of the most fascinating and misunderstood aspects of heart rate variability — low-frequency HRV — and its connection to self-regulation, stress resilience, and overall wellness.

Dr. Khazan begins by breaking down the concept of frequency domains in HRV. Just as white light contains multiple colors, the heart rate signal is composed of several distinct frequency components. Using tools like the Fast Fourier Transform, researchers can separate heart signals into high-frequency, low-frequency, and very-low-frequency ranges — each linked to specific physiological processes and parts of the autonomic nervous system.

The conversation dives deep into low-frequency power, which represents the interplay between the baroreflex (the body’s blood pressure regulation system) and the vagus nerve. Dr. Khazan explains how resonance-frequency breathing—typically practiced for 20 minutes a day—acts like strength training for these systems. Over time, this practice enhances emotional regulation, stress recovery, and overall heart-brain coherence.

Listeners learn that breathing too long in a low-frequency state can actually suppress other important HRV components, such as high-frequency and very-low-frequency power. Instead, Dr. Khazan recommends brief, consistent training sessions to balance all aspects of the nervous system. She also clarifies common misconceptions, including the outdated idea that low-frequency HRV measures sympathetic activity, emphasizing instead its parasympathetic and baroreflex origins.

Matt and Dr. Khazan discuss Optimal HRV’s “Optimal Zone” scale, which tracks the percentage of time users spend in low-frequency dominance during a session. They also unpack metrics like Max-Min and total low-frequency power, explaining how they interact and what each reveals about training efficiency and day-to-day readiness.

Practice resonance-frequency breathing for 20 minutes a day to enhance self-regulation.

Avoid over-training in the low-frequency zone — balance is key.

Understand that low-frequency HRV is not a measure of stress or sympathetic activity, but rather a reflection of vagal and baroreflex strength.

Leverage your Optimal HRV app metrics to track progress, focus, and nervous-system adaptability.

Explore more insights from Dr. Khazan and Matt Bennett on heart rate variability, stress regulation, and biofeedback science.

Visit OptimalHRV.com for resources, show notes, and upcoming episodes, including the "This Week in HRV" series, which highlights the latest HRV research and applications.

Welcome to the show notes for this week’s episode – This Week in HRV Edition. Below, you’ll find direct links to all the studies and articles discussed in this episode. These sources represent the latest research connecting HRV to mental health, resilience, environmental design, and leadership.

Research Studies:

News and Features:

Each of these studies and stories offers a unique perspective on how HRV connects the heart, brain, and body. For more insights, visit our website and subscribe to weekly updates on the evolving science of heart rate variability.

In this episode, we review seven new studies published between September 19 and September 25, 2025. Together, they highlight the many ways HRV intersects with brain activity, breathing practices, cardiac recovery, exercise environments, emergency medicine, environmental stressors, and new multimodal measurement approaches.

We’ll explore:

As always, I’ll connect the research to practical, client-ready strategies you can use right away.

This podcast is sponsored by Optimal HRV. Learn more at optimalhrv.com.