Heart Rate Variability Podcast

Show Notes 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

Resonance Frequency Breathing Explained 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. Resonance Frequency Breathing Techniques 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. Resonance Frequency Breathing Assessment 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. Breathing Patterns and Resonance Frequency 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. Residence Frequency Breathing Assessment 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.

Show Notes 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: Personalized Respiratory Guidance for HRV: Lin, Z., Kong, W., Qiu, S., Luo, M., Wei, J., Guo, X., ... & Dan, G. (2025). High-precision personalized respiratory guidance model for enhanced breathing training: effects on heart rate variability. Biomedical Signal Processing and Control, 100, 108720. https://www.sciencedirect.com/science/article/abs/pii/S1746809425012315 Therapy with Local Anesthetics and HRV: Weinschenk, S., Topbas-Selcuki, N. F., Benrath, J., Strowitzki, T., & Feisst, M. (2025). Effects of therapy with local anesthetics (TLA) on heart rate variability (HRV) over 24 hours. Chronobiology International. https://www.tandfonline.com/doi/full/10.1080/07420528.2025.2560963?src=exp-la Veterans, Service Dogs, and HRV: Krause-Parello, C. A., Friedmann, E., Taber, D., Zhu, H., Quintero, A., & Yount, R. (2025). Veterans Training Service Dogs for Other Veterans: An Animal-Assisted Intervention for Post-Traumatic Stress Disorder. Behavioral Sciences, 15(9), 1180. https://www.mdpi.com/2076-328X/15/9/1180 Circadian Rhythm of HRV in Pregnancy: Rasouli, M., Feli, M., Azimi, I., Haghayegh, S., Sarhaddi, F., Niela-Vilen, H., ... & Rahmani, A. M. (2025). Circadian rhythm of heart rate and heart rate variability in pregnancy. npj Women's Health, 3(1), 57. https://www.nature.com/articles/s44294-025-00107-6 Wearable Tech in Tennis Players: Wang, Z. (2025). Integration of wearable technologies in monitoring physical performance and psychological stress in tennis players. Acta Psychologica, 260, 105706. https://www.sciencedirect.com/science/article/pii/S0001691825010194 Acoustic Features of Chants: Dolan, E. W. (2025, October 6). Chants across cultures share features that promote relaxation. PsyPost. https://www.psypost.org/chants-across-cultures-share-features-that-promote-relaxation/

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. Understanding Frequency Domains in HRV 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. Low Frequency HRV and the Baroreflex 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. Why Breathing Rate and Context Matter 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. Making Sense of HRV Metrics in Optimal HRV 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. Practical Takeaways 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. Listen & Learn More 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: Multisensory environmental effects on HRV and psychological restoration – Scientific Reports Walking through green and grey: Exploring sequential exposure and multisensory environmental effects on psychological restoration – Building and Environment The Impact of Vipassana Meditation on Health and Well-being: A Systematic Review of Current Evidence – Cureus Cardiac timing effects on response speed are modulated by blood pressure, but not by heart rate variability, in healthy young adults – Physiological Reports Heart-brain interaction in emotional regulation – Scientific Reports Environmental stress and HRV in agricultural settings – Agricultural and Forest Meteorology HRV and emotion regulation in depression risk – JAMA Psychiatry HRV modulation through breathing and neural coherence – Frontiers in Human Neuroscience News and Features: Professor honored for pioneering heart–brain research – UC Irvine News Solo practitioner uses HRV tech to improve patient care – Healthcare IT News What is heart rate variability and how can it guide smarter leadership decisions – Manila Bulletin HRV: The new secret weapon for heart resilience – Men’s Health 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: How brain networks and cognitive load shape HRV readings. Why slow breathing alone is powerful, and what feedback really adds. The Benefits of Yoga Nidra for Patients Recovering from Coronary Artery Bypass Surgery. How walking in natural environments provides a stronger autonomic boost than indoor or urban exercise. Real-world HRV findings in emergency medicine and why lab results don’t always translate. How pollution, heat, and noise suppress vagal tone. New frontiers in dynamic and multimodal HRV metrics. 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. References  Behavioural Brain Research – Neural and cognitive influences on autonomic function. https://doi.org/10.1016/j.bbr.2025.115811 Psychophysiology – Comparing HRV biofeedback and slow-paced breathing. https://doi.org/10.1111/psyp.70156 Cureus – Impact of Yoga Nidra on heart rate variability in coronary artery disease patients undergoing coronary artery bypass grafting. https://www.cureus.com/articles/402202-impact-of-yoga-nidra-on-heart-rate-variability-in-coronary-artery-disease-patients-undergoing-coronary-artery-bypass-grafting-a-comparative-study Psychology of Sport and Exercise – Green exercise randomized controlled trial. https://doi.org/10.1016/j.psychsport.2025.102883 International Journal of Emergency Medicine – HRV in emergency medicine contexts. https://intjem.biomedcentral.com/articles/10.1186/s12245-025-00967-4 Environmental Research – Environmental stressors and their impact on HRV. https://doi.org/10.1016/j.envres.2025.122895 Preprint manuscript – Multimodal HRV analytics integrating respiration, voice, and movement. https://pmc.ncbi.nlm.nih.gov/articles/PMC8401087/#:~:text=HRV%20analysis%20is%20performed%20by,equipped%20with%20HRV%20analysis%20modules. 

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