[00:00:00] Happy New Year everyone and welcome back to this week in hrv. I'm Matt Bennett and I'm excited to kick off the year by diving into the latest research on heart rate variability and health. Before we begin, a quick medical disclaimer. This podcast is for educational purposes only. We'll discuss medical studies and health insights, but nothing here is personal medical advice. Always consult your healthcare provider for decisions about your health. With that said, let's jump into our first episode of 2026 with 10 fascinating new studies. We have a great lineup today. From psychosis and heart function to athletes and fatigue to Tai Chi COPD depression screening and more, each study offers insights for clinicians, individuals interested in wellness and researchers alike. Let's get started. First up, a study linking first episode psychosis to heart changes in hrv. The paper is titled Myocardial Deformation and Pro Arrhythmic indices in first episode Patients with Psychosis before and one year after the initiation of Antipsychotic Treatment, published in the Journal of Psychiatric Research. Mario Splakotzis, Eris Bikliolus, Idonis Ramos Spiriton, Sioros Andreas Carampas, Georgios Georgiou Lamprosque, Michalis Caterina K? Naca and Petros Petrikis examined how the hearts of young patients with the first psychotic episode changed over a year of treatment. They followed 33 patients with an average age of around 29 who had never been on antipsychotic medication before. These patients underwent thorough testing, a 24 hour holder ECG to measure heart rate variability and QT intervals, and echocardiography including myocardial strain, a measure of heart muscle function at baseline shortly after the psychotic episode was stabilized. Many of these patients showed concerning cardiac patterns despite having no prior heart disease. For instance, all patients had an abnormal overall HRV index and half had very low SDNNI less than 50 milliseconds, indicating reduced heart rate variability. [00:01:41] One third had unusually low rmssd less than 20 milliseconds, suggesting diminished parasympathetic activity. They also measured QTC intervals. While the average QTC was normal, 30 35% of patients had a maximum QTC above 500 milliseconds at baseline. Importantly, echocardiograms revealed subtle heart dysfunction. About 25% had reduced global longitudinal strain, meaning slightly weakened heart muscle contraction, even though ejection fraction was in the normal range. Now here's the interesting part. After one year of antipsychotic treatment and psychiatric care, some cardiac measures improved while others worsened. On the positive side, patients parasympathetic activity improved for example, PNN50 increased over the year. This suggests their HRV improved in certain aspects, possibly as their mental state stabilized and life became more routine. The heart's pumping function also showed a subtle improvement. Global longitudinal strain became more normal on average, indicating the heart muscle was contracting a bit better. However, there was a trade off. The maximum QTC intervals actually increased slightly after a year on antipsychotics on average from 485 milliseconds to 517 milliseconds. Prolongation of the QT interval is a known side effect of many antipsychotic medications, which can raise arrhythmia risk. The authors conclude that a significant proportion of first episode psychosis patients have subclinical cardiovascular dysfunction and autonomic imbalance from the start. The body is under such stress during acute psychosis that the heart and autonomic nervous system are measurably affected. Treating the psychosis for one year led to improvements in heart function and hrv, likely reflecting better parasympathetic tone as the patients recovered, but also led to longer QT intervals due to medication. The take home message for clinicians is that early psychosis is not just a mental health crisis but also a physical stress on the body. With treatment, the autonomic nervous system can rebalance, but we must remain vigilant about the effects of medication on the heart. Psychiatrists and primary care providers should work together to monitor ECGs and encourage heart healthy lifestyle changes in these patients. This research underscores the mind heart connection. Treating severe mental illness may improve autonomic health and conversely, assessing HRV and cardiac markers might give us clues about how a patient with psychosis is faring physically. Our second study shifts to the world of motor learning and effort and how HRV plays a role in published in Scientific Reports, it's titled Perception of effort decreases with motor Sequence Learning. Bahram Ghaffaragushe, Thomas Mangin, Benjamin Pigot and Jason L. Neva asked a clever as you practice and learn a new motor skill, does it start to feel easier and can we see that change reflected in your heart rate variability? We often assume that as we get better at a task it becomes less mentally and physically taxing. This study test that idea using both psychological and physiological measures. They recruited 30 young adults and had them perform a continuous tracking task while over four sessions. In some blocks the sequence of movements was random, serving as the control condition. In other blocks the sequence repeated and could be learned with practice. After each block, participants rated how much effort it felt like they had to put in. The researchers also recorded heart rate and calculated HRV measures such as rmssd. During these tasks. The results were illuminating. [00:04:27] As expected, people improved at the repeated sequence task. By the final session, they were more skilled and faster than in the random sequence condition. More interestingly, their perceived effort for the repeated sequence dropped significantly. By day two of practice, participants reported that performing the learned sequence felt much less mentally demanding than on day one. In contrast, the random sequences didn't show such a reduction in effort. [00:04:47] Now, on the physiological side, HRV provided an objective window into this process. During the task, participants heart rate and HRV changed with their level of effort and stress. The key finding was that when doing the well learned sequence, people's HRV was higher, specifically rmssd than when doing the unfamiliar random sequence. Higher RMSSD usually indicates a more parasympathetic, calming influence on the heart. So this suggests that once a motor task became automated and easier for the brain, the body also stayed calmer while doing it. The researchers interpreted these findings to mean that motor learning reduces the cognitive and physiological cost of performing a task. When you first learn a new skill, it might be mentally exhausting and ramp up your heart rate, but as you practice and it becomes second nature, you don't need to recruit as many resources. [00:05:28] From a practical standpoint, this study suggests that HRV could be used as an objective marker of how demanding a task is for someone. For instance, trainers or physical therapists might look at a patient's HRV response to an exercise over time. If the HRV stays higher as weeks go by, that might confirm the exercise is becoming more routine for the patient. It also reminds us how intimately connected brain and body are. Learning doesn't just happen in the brain in isolation, it's reflected in the whole body's physiology. Our third study today examines the intersection of chronic infectious disease, inflammation and hrv. This one comes from Curaeus and is titled Serum Cytokine Levels and Heart Rate Variability in the Frequency Domain in patients with Chronic Chagas heart Disease Reynaldo B. Bastetti Sr, Renata Della Libera Hoviano, Milton Faria Jr. Rosemary A. Furlong, Daniel and Claudia C. Domingos investigated how immune system activation relates to autonomic function in people with Chagas cardiomyopathy. Chagas disease is a tropical infection that can lead to chronic heart disease years after the initial infection. Patients with chronic Chagas heart disease often have heart failure, arrhythmias and autonomic dysfunction. We also know that inflammation is a significant part of Chagas. These patients tend to have elevated levels of circulating cytokines. So this study sought to determine whether there's a link between those cytokines and HRV measures, particularly frequency domain indices. They looked at a group of patients with established Chagas heart disease and compared them to healthy controls. They measured a broad panel of cytokines in blood and for HRV focused on frequency domain metrics, primarily the high frequency component and the LF over HF ratio. The headline finding was that Chagas patients had higher levels of nearly all cytokines than healthy people, but most of those cytokines did not correlate with HRV. However, one cytokine did stand out, interleukin 23. They found that IL23 levels were significantly negatively correlated with the high frequency HRV component. In plain language, patients with higher IL23 levels indicating greater inflammation tended to have lower high frequency power indicating less vagal activity. The correlation was moderate but significant with the RRT of approximately minus 0.59. Why might IL23 matter? It is a cytokine involved in specific inflammatory pathways and immune cell differentiation. This finding suggests it may play a role in shad gas related autonomic disturbances. The Authors speculate that IL23 might be part of the inflammatory reflex loop. High IL23 could be a marker of an immune system state that interferes with the vagal control of the heart leading to lower high frequency HRV for clinicians managing Chagas patients. This study underscores the fact that chronic inflammation and autonomic dysfunction go hand in hand Even though only IL23s showed a clear correlation. The overall picture is that these patients have an activated immune system and often a blunted parasympathetic tone. It also raises a hypothesis if we could reduce IL23, would that improve HRV or autonomic function? The researchers provide evidence that in Chagas cardiomyopathy, the more inflamed you are specifically regarding IL23, the more autonomic imbalance you likely have. Clinicians should keep an eye on both controlling inflammation and supporting autonomic health when caring for these patients. Our fourth study takes us to the realm of sports science and youth training camps with an emphasis on HRV as a stress and recovery metric. This one is from Scientific Reports and is titled Research on Changes in Psychological, Physical Fatigue and Emotional States in the National Youth Orienteering Preparation Camp. Hyeon Lee conducted a comprehensive study on teenage athletes, specifically young orienteers who attended a rigorous four week training camp and and compared them to a control group who didn't participate in the camp. The goal was to see how the intensive training program affected their autonomic nervous system, their stress hormones, mood, sleep and fatigue. This study measured many variables. HRV was measured at rest periodically. They also measured morning cortisol, had the athletes fill out stress and mood questionnaires, tracked their sleep quality and duration, and recorded perceived exertion during training sessions. The camp wasn't just physical training it included mental skills training and a structured daily routine to optimize performance and recovery. The control group just continued their usual training at their home schools. The findings were very encouraging for structured training camps. Over the month, the orienteering camp group showed significant improvements in their HRV compared to controls. For instance, their resting rmssd increased from about 45 milliseconds at baseline to about 55 milliseconds by the end of the camp. Meanwhile, the control group's RMSSD slightly decreased over the same period. This suggests the structured program boosted their autonomic recovery or resilience. Similarly, the camp group's cortisol levels dropped over the four weeks, whereas the control group's cortisol slightly rose. High cortisol levels can indicate chronic stress. Seeing a drop in the campgroup suggests they adapted to the training and benefited from their recovery protocols. Psychologically, the athletes at camp reported feeling less stressed and having a better mood as the weeks went on. They also showed increases in positive emotions and decreases in negative emotions on the mood questionnaires. Moreover, sleep improved for the camp kids. The they got roughly half an hour more sleep per night on average by the end of camp and rated their sleep quality higher than the controls. Even their perceived exertion during training sessions decreased over the weeks, making the workouts feel easier. In summary, this training camp by Haiyan Li not only made the athletes fitter but also healthier in a holistic sense. Better autonomic tone, lower stress hormones, improved mood and better sleep are all markers of a well conditioned and well recovered athlete. It suggests that a carefully designed program can produce positive adaptations rather than just fatigue for coaches and sports scientists. This highlights the importance of mental health and emotional well being in training. These athletes likely benefited from team camaraderie and coaching support. Our fifth study is a deep dive into the neuroimmune aspect of heart health, particularly in diabetes. Xin Ruizhou, Xiaowei, Bai, Li, Ding, Shuai, Jiang and Yali published an article titled Autonomic Inflammatory Crosstalk and Diabetic Atherogenesis. A Neuroimmune Triad HRV, LMR, HSCRP Predicts Carotid Plaque Risk in Type 2 Diabetes they studied patients with type 2 diabetes and tried to predict who is at risk of developing atherosclerosis. The triad they mention is hrv, LMR and hscrp. HRV is a marker of autonomic nervous system function. LMR is the lymphocyte to monocyte ratio, reflecting immune status. HSCRP is high sensitivity C reactive protein, a classic blood marker of inflammation. So basically they combined an Autonomic marker with 2 immune inflammatory markers to see whether together they could better flag diabetic patients with carotid plaques. What did they find? In their cohort, those with evidence of carotid atherosclerotic plaques had a distinct profile lower hrv, lower LMR and higher CRP levels than those without plaques. Lower HRV especially indicates higher sympathetic and lower parasympathetic tone. A low LMR indicates the person had more monocytes than lymphocytes. Since monocytes drive inflammation in blood vessels, a low LMR is a proxy for a pro inflammatory state. The research showed that when you put these three factors together, they predicted the presence of carotid plaques quite well and in fact they argue that this triad was an independent predictor even after accounting for traditional risk factors. This implies that we can improve risk stratification by checking autonomic and immune health. Poor blood sugar control and insulin resistance cause inflammation. Chronic inflammation can in turn affect the autonomic nervous system. Sustained sympathetic activation can contribute to hypertension and plaque formation, so it becomes a vicious cycle for clinicians. This study suggests a practical screening framework. Consider measuring HRV alongside a simple blood panel in patients with type 2 diabetes. If all signs point to trouble treatment, that patient might benefit from aggressive cardiovascular risk reduction. It's a step towards personalized medicine. Not all diabetics have equal cardiac risk and this triad could help identify those who need more intensive prevention efforts. This week in HRV is brought to you by Optimal hrv. Optimal HRV is the platform I trust for making heart rate variability accessible and valuable for everyone from health professionals to individuals at home. The Optimal HRV app and training programs help you measure your stress and recovery, understand your body's signals and improve your overall well being. It combines user friendly technology with expert guidance so you can truly harness the power of HRV to manage stress, enhance performance and support mental health. As we start the new year, it's a perfect time to get serious about your health metrics. Check out the Optimal HRV app or their website to learn how you can integrate HRV tracking into your daily routine or clinical practice. Big thanks to optimal HRV for sponsoring this episode and for their commitment to improving health one heartbeat at a time. [00:13:08] Alright, back to the research. Our sixth study deals with mind body exercises, specifically Tai Chi and qigong and their effect on hrv. This is a meta analysis titled Effective Tai Chi and Qigong on Heart Rate Variability A Systematic review and Meta Analysis examining Baseline autonomic function and Intervention Complexity as moderators in adults. Yasmine A. Genawan Mainwe, Suan Hanifa M. Deni, Ishita Chauhan, Milcha Fakria Siswijayanti and Earl fi Mullari aggregated data from 15 studies to quantify the influence of these practices on on hrv. Tai chi and qigong are known to reduce stress and improve balance and HRV is a logical outcome to examine as these exercises involve breath control and relaxation. The meta analysis specifically examined time domain HRV measures such as SDNN and rmssd. The pooled results were quite positive. Tai chi and qigong had a moderate overall effect on improving hrv. When all the data were combined, the practice significantly increased SDNN and rmssd. These improvements are associated with better autonomic balance. [00:14:05] An interesting finding was that people with relatively normal baseline HRV showed larger improvements from Tai chi and qigong than those with very low baseline hrv. This might reflect a ceiling effect in some healthy individuals or conversely indicate that in people with severe autonomic impairment, these light exercises alone aren't enough to change HRV dramatically. On the other hand, the complexity of the Tai Chi or qigong routine did not affect the outcomes. Whether the study used a simple qigong exercise or a more elaborate routine, the HRV improvements were similar. [00:14:31] This is excellent news because it implies that even simple beginner friendly routines can confer HRV benefits for practitioners and individuals. If you're looking for a low impact way to improve your stress resilience, these practices are a solid option. Clinicians might consider recommending Tai chi or qigong as part of a holistic plan to improve cardiovascular autonomic health, especially for those who can't do vigorous exercise. This research reinforces the value of ancient practices in modern medicine. A little mindful movement can yield quantifiable benefits for heart rate variability. Our seventh study today highlights a sympathovagal imbalance in the context of respiratory disease, specifically copd. Dirjesh K. Gupta, Shibu S. Awashti Sumangupta and Himani H. Moore published this study titled Sympathovagal Imbalance in Drug naive chronic obstructive pulmonary disease patients a physiological mechanism to cope with the severity of airway obstruction. This was an observational case control study. They took 72 patients with COPD who'd never been on COPD medications and compared them to 72 and healthy controls. They measured lung function via spirometry and assessed autonomic behavior using the LF HF ratio. The results were quite clear. COPD patients had a significantly higher LF over HF ratio than healthy controls. In numbers, the average ratio was about 1.34 compared with 1.05 in controls. It indicates that at rest, the COPD group had more sympathetic than parasympathetic activity. But even more interesting was how that ratio related to lung function within the COPD patients. Those with worse airflow had higher LF HF ratios. In fact, the correlation between lf HF and FEV1 was strongly inverse with a robust R of approximately minus 0.77. The researchers interpret these findings as evidence of a physiological coping mechanism. They hypothesized that as COPD patients experience airway obstruction, the body reflexively increases sympathetic drive, perhaps to keep airways open or to maintain oxygenation. Sympathetic activation can lead to bronchodilation, so the body might be boosting sympathetic tone to counteract the obstructed airways. However, that comes at a cost. Chronic sympathetic overdrive is not great for the heart, which could contribute to the high cardiovascular risk seen in COPD patients. For clinicians, it highlights why COPD isn't just about the lungs. It's a systemic condition that affects autonomic regulation. It might partially explain why COPD patients often have resting tachycardia or a higher incidence of arrhythmias when managing copd. We should also consider interventions such as pulmonary rehabilitation or breathing techniques to rebalance the autonomic system. [00:16:49] Our eighth study involves another network analysis, this time in the context of autism spectrum disorder and irritability. Sarah Alatrash, Titi Paul, Brendan F. Andrade, Sunita Manga, Jessica Bryan, Evdokia Anagnostu, Melanie Pinner, Atina, Roshan, Fekar, and Azadikushki published irritability in autism examined through network analysis of phenotypic and physiological correlates in scientific reports, irritability in autism is a common and challenging symptom, often accompanied by anxiety or ADHD symptoms. Physiologically, autonomic dysregulation has also been observed. The researchers wanted to understand how irritability relates to both behavior and underlying physiology. They used a network analysis approach to map the interconnections among various factors. The key findings were that irritability in autism was not an isolated symptom it was centrally connected to externalizing behaviors and emotion dysregulation. Concerning the physiological part, heart rate variability and heart rate reactivity were indirectly related to irritability. The network analysis showed that these physiological measures connected to irritability through their association with self regulation skills and ADHD like traits. In other words, children with poor autonomic regulation often had weaker self regulatory abilities which in turn were associated with greater irritability. It wasn't a direct HRV link but a chain of influences. The big picture message is that irritability should be seen as part of a web of interconnected factors. Clinically treating irritability requires a multi pronged approach including behavioral therapy to improve emotion regulation and and interventions to enhance autonomic regulation such as biofeedback. It's also a reminder that when we see a child with autism who is extremely irritable, we should check for other issues like sleep problems or sensory overload. This study shows that meltdowns are not just willful misbehavior. They often reflect an overwhelm system in which biology and environment aren't in sync. The ninth study brings us to the world of mental health screening with an innovative twist using HRV and emotions. Ji Bin, Juany Wang, Yifei Xiu Wanlin Chen, Jing Zheng, Xu Lin Chen and Hong Chen presented a heart rate variability driven framework for depression screening. Leveraging emotion elicited autonomic divergence. They tried to detect depression by looking at how people's HRV responds to emotional challenges rather than just at rest. While many studies have found that people with depression have lower resting hrv, using that alone as a diagnostic tool hasn't been accurate enough. The researchers thought if we stress the system by showing something sad or happy, but we might unveil differences in autonomic reactivity. In their study, they had individuals with clinically diagnosed depression and healthy controls. They exposed everyone to emotional elicitation tasks, sadness, happiness, anger, fear and a neutral condition. They recorded various HRV features and used machine learning models to classify who was depressed. The results were striking. The HRV response during SAD emotion was the most potent at distinguishing depressed individuals. The model based on the SAD condition had about 77% accuracy. In contrast, using HRV data from a neutral resting state was barely better than chance. They found that depressed individuals had an augmented physiological response to sadness and a muted response to happiness compared to controls. Imagine a short test where a patient watches a brief emotional video while a device records their heart signals. If the pattern of HRV changes matches the profile associated with depression, the tool could flag that it's akin to a cardiac stress test, but for mental health, an objective test could complement current screening questionnaires. From a clinical standpoint, this reinforces that depression has physiological correlates and in how one reacts to emotional stress. It also has a hopeful side. If specific emotional reactivity patterns normalize with treatment, HRV could potentially be a marker of recovery or resilience. Finally, our 10th study is a comprehensive review addressing the connection between PTSD and cardiovascular disease. Malikay Alariki, Ivan Karpenko, Grigori Asion, Anvar K. Jumanov, Shirin Dadaev, Hassan Sagar, Darya Koranjaya, Zlata Kurant, Valeria Gavorgian, Anastasia V. Butlereva, Alexey M. Kirachev, Mohammad Ayad Haya Darwish and Abubakar Far Siddiq wrote. Epidemiological link between Post traumatic stress disorder and cardiovascular Evidence, mechanisms and clinical implications this paper pulls together research showing that people with PTSD have more heart attacks and strokes. Multiple meta analyses have shown that PTSD is associated with a significant increase in risk for developing hypertension, coronary artery disease and heart failure. One meta analysis indicated up to a 60% higher risk of cardiovascular morbidity in those with PTSD. The review outlined several pathways, primarily the chronic activation of the sympathoadrenal system and the HPA axis. PTSD is characterized by hyperarousal patients, often have an exaggerated fight or flight response, with higher resting heart rates and typically lower HRV over the years. This autonomic imbalance can lead to arterial wall stress and accelerated atherosclerosis. Another mechanism is inflammation. PTSD is linked to higher levels of markers like CRP and IL6 behavioral factors also play a role. PTSD often coexists with smoking, poor diet and sleep disturbances. Compounding risk. The researchers emphasize that healthcare providers should consider PTSD as an independent risk factor for cardiovascular disease. This means screening these patients earlier and more frequently. Integrated care is essential. Treating PTSD might help the heart, and therapies like exercise training and HRV biofeedback have shown promise in both symptom reduction and improving autonomic function. They call for an interdisciplinary approach where cardiologists and mental health professionals work together that wraps up our study reviews. So now let's distill some practical insights from all this. We've covered a lot of ground mental health, exercise, inflammation, technology, but the common thread is heart rate variability and autonomic balance as a lens for health. For clinicians, one takeaway is the increasing recognition that HRV and autonomic measures can provide early warning signs. Whether it's a first episode psychosis patient, a diabetic patient or a veteran with ptsd, checking on their autonomic status might reveal hidden stress on the body. It can guide you to intervene sooner. Also, HRV is proving helpful in monitoring treatment effects in youth training camps or Tai Chi studies. Improvements in HRV reflected better health and recovery for individuals and non clinicians. Many of these studies reinforce healthy habits. Getting good sleep, exercising and practicing relaxation can boost your hrv, which is a proxy for your stress resilience. That's not just an abstract benefit. Higher HRV is linked with lower inflammation, better mood and and lower risk of heart issues. If you're dealing with a chronic condition, paying attention to self care that improves your autonomic balance could improve your overall outcomes. For researchers, the range of studies we discussed highlights the value of multidisciplinary research. We saw psychology blending with physiology and traditional medicine blending with tech as we move forward in 2026, one theme is clear. Heart rate variability is coming of age in both research and practice. It's not just a niche metric for athletes anymore, it's relevant in psychiatry, pulmonology, endocrinology and beyond. [00:23:04] The autonomic nervous system is a common denominator in health and HRV is our window into it to close. What I find heartening is that many interventions that improve hrv, such as exercise, mindful breathing and better sleep are accessible and low cost. It's a good reminder that high tech medicine and low tech lifestyle often need to go hand in hand. That's all for today's this Week in HRV podcast. Thank you for joining me in exploring these 10 critical studies we navigated from the cardiac effects of psychosis and antipsychotics to athletic training, adaptations to the benefits of Tai Chi and the risks of PTSD on the heart. If you found this helpful discussion, please subscribe to the podcast and consider leaving a review. We'll continue to bring you the latest HRV research and what it means for you and your work. In upcoming episodes we'll cover topics such as HRV and long Covid, new wearable tech validations and more. Remember, your heart rate variability reflects your day to day health. So as you go into the new year, take care of yourself, stay active, manage that stress and keep an eye on those recovery metrics. Thank you again for listening to the Heart Rate Variability Podcast I'm Matt Bennett, and I wish you a healthy, resilient and balanced week ahead. Join us next time for more insights on the tiny beats that power your life. Be well and Happy New Year.