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Cardiac coherence: A new, noninvasive measure of autonomic nervous system order

Authors:
  • Independent Researcher

Abstract

Although cardiac sympathovagal regulation has been studied during stress using power spectral density analysis of heart rate variability, little is known about its regulation during emotional states. Using heart rate variability measurements, we studied autonomic balance in 20 subjects trained in a mental and emotional self-management technique called Freeze-Frame. The study was conducted in two environments: under controlled laboratory conditions, and under real-life stressful conditions in the workplace. Power spectral density plots of R-R intervals obtained from electrocardiogram recordings were divided into three regions: low frequency (predominantly sympathetic activity), midfrequency, and high frequency (parasympathetic activity). Measurements were taken for a 5-minute baseline period, followed by a 5-minute period of positive emotional expression. Three unique conditions of autonomic nervous system order can be clearly discriminated in the data: (1) normal heart function mode, (2) entrainment mode, and (3) internal coherence mode. The internal coherence mode is new to the electrophysiology literature. We provide supporting data for modes 2 and 3 and show that a group of 20 subjects trained in this technique can enter and maintain these states at will. We found that, when one is in the entrainment mode, other physiological systems lock to the entrainment frequency, which is approximately 0.1 Hz. The results suggest that emotional experiences play a role in determining sympathovagal balance independent of heart rate and respiration and further suggest that positive emotions lead to alterations in heart rate variability that may be beneficial in the treatment of hypertension and reduce the likelihood of sudden death in patients with congestive heart failure and coronary artery disease.
... In earlier studies, we found that emotional states such as anger and appreciation are reflected differently in the patterns of the heart rhythm and in the power spectra 25 . In past studies 26,27 the focus was on the self-induction of various emotions and without any mention of altering one's breathing pattern. These studies found that participant's breathing rhythms co-varied with the emotions they were experiencing suggesting that the brain structures above the cardiorespiratory integration centers in the dorsal vagal complex involved in emotional processing and experience (amygdala, etc.) were unconsciously modifying the breathing rhythm, which is reflected in changes in the heart rhythm 4 . ...
... The spectral analysis of Inter-Beat Interval (IBI) data established that the most common frequency is around 0.10 Hz during practice sessions across all coherence scores with the exception of the 0-1 level. This was not surprising as numerous studies have found this frequency is associated with the baroreflex system which regulates short-term blood changes 56 and is at the center of the Coherence Range where frequency entrainment of the respiratory, beatto-beat blood pressure and heart rhythms and increased heart-brain synchronization typically occurs 4,26 . What was surprising is that for many of the more experienced users with the highest levels of heart rhythm coherence, their frequency was in the lower end of the Coherence Range (see Fig. 4). ...
... The observed trends suggest a complex interplay between respiration, beat-to-beat blood pressure regulation and activity in both the afferent and efferent activity in the autonomic nervous system. For instance, the expected increase in the LF/HF ratio in higher coherence levels was due to large an increase in low-frequency power, which is often associated with enhanced baroreflex function and increased afferent vagal traffic 18,26,66 . This increase in low-frequency power is typically due to an increase in the amplitude of the HRV rhythm and by a more regular sine-wave like rhythmic heart rate pattern in the LF region of the spectrum 4,26,67 . ...
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This global study analyzed data from the largest dataset ever studied in the Heart Rate Variability (HRV) biofeedback field, comprising 1.8 million user sessions collected from users of a mobile app during 2019 and 2020. We focused on HRV Coherence, which is linked to improved emotional stability and cognitive function. Positive emotions reported by users were associated with higher Coherence scores and more stable HRV frequencies. In contrast, negative emotions exhibited lower scores and more dispersed frequency distributions. The most common frequency associated with Coherence was identified at 0.10 Hz. However, many users with the highest levels of Coherence fell within a lower range from 0.04 to 0.10 Hz. Most users exhibited high stability (standard deviation < 0.012 Hz) in their coherence frequencies from session to session, and their stability within a given session increased with increasing Coherence. The insights gained from this extensive dataset suggest that by instructing users to breathe deeper and slower and find a rhythm that’s comfortable, they naturally find their unique resonant frequency. The findings provide a strong foundation for future research and the development of targeted interventions aimed at enhancing emotional and physiological well-being through HRV biofeedback and coherence practices.
... The "heart's rhythmic beating patterns not only reflect the individual's emotional state, but they also play a direct role in determining emotional experience." 8 A ground-breaking discovery at the Institute of HeartMath, found that when self-induced by adoption of a loving focus the heart entrains the brain, the psychophysiological system, and the other major systems of the body into a state of system-wide Psychophysiological Coherence (20) (Figure 2), as Tiller explains: ...
... This suggests that the heart is directly coupled to a subtle energetic field of ambient information that surrounds the body which, in turn, is entangled and interacts with the multiplicity of energy fields in which the body is embedded-including that of the quantum vacuum. 20 Moreover, there were gender differences pointing to the involvement of love, in that the females, when in a self-induced state of heart coherence, displayed a significant difference in the pre-stimulus HRV curves for the Emotional versus Calm pictures, whereas the males did not. These results, showing the heart's direct involvement in intuitive perception, have been corroborated in subsequent studies (6,7,8,31,32). ...
Article
The focus of this work is the heart’s vital role in creation. How the heart, when in a state of unconditional love, generates a coherent field of psychoenergetic connection, which enables mind and spirit to shape reality. Of the research I draw on, two are studies of monumental importance—Margins of Reality (26) and Some Science Adventures with Real Magic (5). These works show, unambiguously, the crucial role unconditional love plays in psychic phenomena, such as intuitive perception and focused intention. Of import, in the latter, William Tiller and his associates (5) document how focused intention can induce change in physical reality, when cocooned in an envelope of heart coherence. This prompts creation of a ‘new’ dimension of order in the quantum vacuum, and also enables access to its ginormous store of ‘free’ energy to power the change. Electrophysiological evidence suggests this is a Hyper State of coherence which, in the ECG spectrum, extends as a harmonic series likely, via multiscale entanglement, to the quantum domain. To explain the psychoenergetic processes involved in psychic interactions, the principles of classical and quantum holography are used. In essence, attentional/intentional focus, when mediated by sustained heart coherence, creates a phase-conjoined-adaptive-resonant (PCAR) channel of nonlocal communication. Through this channel, holographically encoded information about remote/future events (intuition) is received, or focused intention is transmitted. It is postulated that such will-induced change—psi-formation—occurs by way of oscillatory entrainment. In this process the target’s system is frequency-pulled, via sustained intentional focus, to the image of order holographically encoded in the agent’s intention. A set of equations delineate the relations among the key factors involved in these psycho energetic processes of creation. These point to a basic equation expressing the creation relations among the fundamental constituents of reality: Love, Consciousness, Energy, and Matter.
... Hence, respiratory-related, efferent, vagally mediated influences are present in the LF band when breathing with a slow respiration rate. [24,25] SDNN is also contributed to by both the sympathetic and parasympathetic nervous systems. [26,27] However, in short-term recordings of around 5 min involving slow regulated breathing, as in the present study, the main source of SDNN is parasympathetically-mediated respiratory sinus arrhythmia. ...
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Background Previous studies of nostril-regulated yoga breathing have focused on unilateral breathing with both inspiration and expiration through a specified nostril. However, traditionally described yoga breathing involves inspiration through one nostril and expiration through the other, called suryabhedan pranayama (SBP) (right nostril inspiration) and chandrabhedan pranayama (CBP) (left nostril inspiration). The effects of these practices were investigated here. Methods Forty-seven healthy male participants (group mean age ± standard deviation [SD]; 26.34 ± 6.38 years) with prior experience of yoga breathing (group mean age ± SD; 43.64 ± 32.84 months) were randomly assigned to four sessions on separate days: (i) SBP, (ii) CBP, (iii) Breath awareness, and (iv) Quiet rest. The heart rate variability (HRV) and breath rate were recorded pre, during, and post each practice. Results There was a significant increase in low frequency (LF) power and SD of NN intervals during SBP and CBP in comparison to the respective preceding ( P < 0.05; repeated measures analyses of variance with Bonferroni adjusted post hoc analysis), while LF increased post-CBP alone. During both interventions, there were significant reductions in respiration rate. Conclusion The changes in HRV suggest common rather than distinct changes in SBP and CBP suggestive of respiration-related increased cardiac parasympathetic activity. The involvement of both nostrils in SBP and CBP may have contributed to the comparable effects of the two practices.
... Exposure to physical and mental stress, such as the environment of wildfire fighting, is reflected in cardiac adaptations associated with vagal flow [77]. The oscillations in the LF band (p-value = 0.002) indicate slow respiratory cycles, meaning that the influences of the environment on respiratory cycles may explain these alterations [78]. The nozzle/rope tasks present more fluctuating values, and there may be a direct relationship with greater exposure to fire smoke. ...
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Wildland firefighting is physically and mentally demanding. The aerobic capacity of firefighters is important due to the demands of the activity and the associated occupational risks. The main objectives of this study were to identify and characterise the physically demanding tasks undertaken by volunteer firefighters during wildland fires (real work conditions). A total of 125 firefighters replied to a survey about sociodemographic, biometric data, and work fitness assessment. A group of 23 was evaluated in a physical stress test using a VO2peak protocol to determine maximum oxygen consumption and ventilatory thresholds. The physical demands and physiological responses were collected during the operations at the firefront (n = 21). The results revealed that wildland firefighting entails physical demands that exceed established reference values, with maximum oxygen uptake exceeding 40%. The cardiovascular strain is particularly notable in tasks performed near the firefront, reflecting fatigue. The physical and cardiac demands associated with forest fire fighting have been demonstrated to contribute to occupational illnesses with prolonged exposure. This study underscores the imperative for interventions to enhance the identification and real-time monitoring of physiological parameters to enhance firefighters' overall health and well-being.
... As mentioned previously, the HRV measure assessed in this intervention is independent of standard time and frequency measures for HRV (Shaffer and Ginsberg 2017), and rather a measure of cardiac coherence, the harmonic wavelike properties of a heart rate over time ( . While states of higher HRV cardiac coherence have been linked to positive emotions such as appreciation and compassion (McCraty et al. 1995;Tiller, McCraty, and Atkinson 1996) and cardiac coherence (measured as 'coherence' in the study device and cited as 'HRV coherence' in this study), activated by the practice of slow-paced breathing due to respiratory sinus arrhythmia, or the natural variation of heart rate over the breath cycle has been linked to increased selfregulation (McCraty and Zayas 2014), the lack of relationship between coherence and standard HRV metrics limits the interpretation of our results. The study protocol emphasised to study participants the importance of not only learning and practicing the techniques taught in study sessions, but employing these tactics in times of stress, emphasising stressful situations in the workplace, in this case the COVID-19 frontline milieu. ...
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Psychological stress among frontline healthcare workers (HCWs) increased during the COVID‐19 pandemic, elevating mental health risks. Heart rate variability biofeedback (HRV‐BF) is an evidence‐based intervention with potential to reduce psychological burden on frontline HCWs; however, no studies have examined its use among this population since the pandemic began. We designed a trial to assess the effects of a brief HRV‐BF intervention delivered via telemedicine on measures of anxiety, depression and stress, and heart rate variability, compared to an in‐person intervention. We hypothesised that the telemedicine intervention would be non‐inferior to the in‐person intervention. Using a randomized comparison trial design, we tested a 10‐day brief heart rate variability biofeedback intervention among frontline HCWs during the COVID‐19 pandemic. They received remote, 30‐min guided sessions every other day and were taught methods of heart rate variability biofeedback. Depression, anxiety and stress were assessed at baseline, 10 days, and 40 days with additional measures of anxiety measured before and after each session. HRV scores were collected at baseline, as well as during the course of the 10 days. Multilevel modelling was used to examine the change in depression, anxiety, stress and HRV scores across multiple time points and session types (telemedicine vs. in‐person). There was no significant differences between telemedicine ( n = 32) and in‐person ( n = 15) interventions on the main outcomes. Both session types showed a significant decrease in depression, anxiety and stress scores across the entire intervention, and HRV scores significantly increased across both groups. Anxiety levels also significantly decreased after each session. The non‐inferiority of the telemedicine intervention to a comparable in‐person intervention affirms its promise for decreasing anxiety, depression and stress among frontline HCWs and may offer a cost‐effective and feasible tool to use in crises situations.
... Participants underwent a 10 min data collection session that captured the average coherence score for the session. A higher coherence score represents a more coherent heart rhythm and is associated with lower stress and a more positive emotional state [32,48]. ...
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Understanding how interventions reduce psychological distress in patients with prostate cancer is crucial for improving patient care. This study examined the roles of self-efficacy, illness perceptions, and heart rhythm coherence in mediating the effects of the Prostate Cancer Patient Empowerment Program (PC-PEP) on psychological distress compared to standard care. In a randomized controlled trial, 128 patients were assigned to either the PC-PEP intervention or standard care. The PC-PEP, a six-month program emphasizing daily healthy living habits, included relaxation and stress management, diet, exercise, pelvic floor muscle exercises, and strategies to improve relationships and intimacy, with daily activities supported by online resources and live sessions. Participants in the intervention group showed significant improvements in self-efficacy and specific illness perceptions, such as personal control and emotional response, compared to the control group. These factors mediated the relationship between the intervention and its psychological benefits, with self-efficacy accounting for 52% of the reduction in psychological distress. No significant differences in heart rhythm coherence were observed. This study highlights the critical role of self-efficacy and illness perceptions in enhancing psychological health in prostate cancer patients through the PC-PEP. The results underscore this program’s effectiveness and the key mechanisms through which it operates. Given the high rates of distress among men undergoing prostate cancer treatments, these findings emphasize the importance of integrating the PC-PEP into clinical practice. The implementation of the PC-PEP in clinical settings can provide a structured approach to reducing psychological distress and improving overall patient well-being.
... This state involves a shift towards order, harmony of physiological and psychological processes, and synchronisation, which results in the generation of a heart rate wave form of a smooth sinewave at a frequency of 0.1 Hz. There is less activation of the sympathetic nervous system and greater parasympathetic activity, a better heart-brain synchronisation and great resonance between various physiological systems ) (Tiller et al. 1996). This increased physiological coherence directly affects physical functions, cognitive functions, and task performance because of improvements in focus, attention, accuracy, and speed of responses, greater emotional stability, decreased perception of stress and negative emotions. ...
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This systematic review evaluates interventions aimed at reducing exam anxiety in adolescents, revealing that various methods, such as Cognitive Behavioural Therapy (CBT), mindfulness, emotional self-regulation, expressive writing, attention training, multimodal cognitive-behavioural approaches, hypnosis, and working memory training, significantly lower anxiety levels. By thorough quality assessment and data extraction from ten included studies, this paper highlights the effective interventions, urging future research to refine these interventions and explore their long-term benefits. Educators and practitioners are recommended to adopt these evidence-based strategies to enhance students' academic performance and psychological health.
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Intuition is generally taken as a belief, experience, and tool for knowledge emergence, often characterized by emotional judgments, sensations or foresight and be classified into various types. Recently researchers have started to search for somatic markers for intuition using EEG and ECG. The objective of this study is to explore the correlations between measurements that serve as indicators of heart rate variability and the strength and kind of intuition based on samples self-reports. The samples are 149 students aged 19-21 at Kocaeli University. Data was collected using KYTO2935 HRV sensors, Elite HRV Bluetooth application and the Intuitive Thinking Scale. Research findings indicate correlations between intuitive thinking skills and certain sub-dimensions and specific heart rhythm indices. These correlations vary in terms of their effect sizes, but it is satisfactory to assert that certain features of ours, which are acknowledged as intuitive thinking abilities, are connected to heart rhythm indices and require more thorough investigations.
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