Changes In Heart Rate Variability Research Articles

Synchronization between music dynamics and heart rhythm is modulated by the musician's emotional involvement: A single case study.

In this study we evaluated heart rate variability (HRV) changes in a pianist, playing in a laboratory, to investigate whether HRV changes are guided by music temporal features or by technical difficulty and/or subjective factors (e.g., experienced effort). The pianist was equipped with a wearable telemetry device for ECG recording during the execution of 4 classical and 5 jazz pieces. From ECG we derived the RR intervals series (tachogram), and, for each piece, analyzed HRV in the time (RR, RMSSD, Stress Index) and frequency domains (Total spectral power) and performed non-linear analysis (Multiscale Entropy). We also studied the correlation (Pearson) between the time course of music volume envelope and tachogram. Results showed a general reduction of parasympathetic and an increase of sympathetic activity, with the greatest changes during the classical pieces execution, the pianist appraised as more demanding than the jazz ones. The most marked changes occurred during the most technically/emotionally demanding piece, and correlation analysis revealed a negative association between music volume envelope time course and tachogram only for this piece, suggesting a modulation of the limbic system on the synchronization between heart rhythm and music temporal features. Classical music was also associated with the increase of entropy (1st scale) with respect to rest, indicating its effectiveness in driving flexible, healthy, heart dynamics. In conclusion, HRV seems modulated not only by the music temporal features, but also by the pianist’s emotional involvement, which is greatly influenced, in a non-trivial manner, by the technical demands and musician expertise.

Heart Disease and Arboviruses: A Systematic Review and Meta-Analysis.

Dengue fever, chikungunya, and zika are highly prevalent arboviruses transmitted by hematophagous arthropods, with a widely neglected impact in developing countries. These diseases cause acute illness in diverse populations, as well as potential cardiovascular complications. A systematic review was carried out to investigate the burden of cardiac involvement related to these arboviruses. Multiple databases were searched for articles that investigated the association of cardiovascular diseases with arboviruses, published up to March 2022. Relevant articles were selected and rated by two independent reviewers. Proportion meta-analysis was applied to assess the frequency-weighted mean of the cardiovascular findings. A total of 42 articles were selected (n = 76,678 individuals), with 17 manuscripts on dengue and 6 manuscripts on chikungunya undergoing meta-analysis. The global pooled incidence of cardiac events in dengue fever using a meta-analysis was 27.21% (95% CI 20.21–34.83; I2 = 94%). The higher incidence of dengue-related myocarditis was found in the population younger than 20 years old (33.85%; 95% CI 0.00–89.20; I2 = 99%). Considering the studies on chikungunya (n = 372), the global pooled incidence of cardiac involvement using a meta-analysis was 32.81% (95% CI 09.58–61.49, I2 = 96%). Two Zika studies were included that examined cases of infection by vertical transmission in Brazil, finding everything from structural changes to changes in heart rate variability that increase the risk of sudden death. In conclusion, cardiac involvement in arboviruses is not uncommon, especially in dengue fever.

Heart rate variability changes in patients with obstructive sleep apnea: A systematic review and meta-analysis.

Obstructive sleep apnea is a common sleep breathing disorder related to autonomic nervous function disturbances. Heart rate variability is an important non-invasive indicator of autonomic nervous system function. The PubMed, Embase, Medline and Web of Science databases were systematically searched for English literature comparing patients with obstructive sleep apnea with controls up to May 2021. Heart rate variability outcomes, including integrated indices (parasympathetic function and total variability), time domain indices (the standard deviation of NN intervals and the root mean square of the successive differences between normal heartbeats) and frequency domain indices (high-frequency, low-frequency, very-low-frequency and the ratio of low-frequency to high-frequency) were derived from the studies. Twenty-two studies that included 2565 patients with obstructive sleep apnea and 1089 healthy controls were included. Compared with controls, patients with obstructive sleep apnea exhibited significantly reduced parasympathetic function. For the obstructive sleep apnea severity subgroup meta-analysis, patients with severe obstructive sleep apnea had significantly lower parasympathetic function, high-frequency, root mean square of the successive differences between normal heartbeats and standard deviation of NN intervals, and higher low-frequency and ratios of low-frequency to high-frequency. However, only the ratio of low-frequency to high-frequency was significantly higher in patients with moderate obstructive sleep apnea than in controls. Finally, for the collection time analysis, patients with obstructive sleep apnea had significantly higher low-frequency and ratio of low-frequency to high-frequency at night, significantly lower parasympathetic function, high-frequency, root mean square of the successive differences between normal heartbeats and standard deviation of NN intervals, and a higher ratio of low-frequency to high-frequency during the day than controls. Autonomic function impairment was more serious in patients with severe obstructive sleep apnea. During sleep, low-frequency can well reflect the impairment of autonomic function in obstructive sleep apnea, and the ratio of low-frequency to high-frequency may play an important role in obstructive sleep apnea diagnosis.

Decrease of heart rate variability during exercise: An index of cardiorespiratory fitness.

The present study proposes to measure and quantify the heart rate variability (HRV) changes during effort as a function of the heart rate and to test the capacity of the produced indices to predict cardiorespiratory fitness measures. Therefore, the beat-to-beat cardiac time interval series of 18 adolescent athletes (15.2 ± 2.0 years) measured during maximal graded effort test were detrended using a dynamical first-order differential equation model. HRV was then calculated as the standard deviation of the detrended RR intervals (SDRR) within successive windows of one minute. The variation of this measure of HRV during exercise is properly fitted by an exponential decrease of the heart rate: the SDRR is divided by 2 every increase of heart rate of 20 beats/min. The HR increase necessary to divide by 2 the HRV is linearly inversely correlated with the maximum oxygen consumption (r = -0.60, p = 0.006), the maximal aerobic power (r = -0.62, p = 0.006), and, to a lesser extent, to the power at the ventilatory thresholds (r = -0.53, p = 0.02 and r = -0.47, p = 0.05 for the first and second threshold). It indicates that the decrease of the HRV when the heart rate increases is faster among athletes with better fitness. This analysis, based only on cardiac measurements, provides a promising tool for the study of cardiac measurements generated by portable devices.

Modulation of the autonomic nervous system by one session of spinal low-level laser therapy in patients with chronic colonic motility dysfunction.

Patients with a defecation disorder may not evoke a normal defecation reflex, or the reflex may be excessive, as a dysfunction of the spinal autonomic nervous system. Treatment with various forms of lumbar and sacral neuromodulation have shown symptom improvement, but potential changes in autonomic functioning are rarely studied. Here we evaluate the effects on autonomic function of a single session of low-level laser therapy (LLLT) on the lumbar and sacral spine in 41 patients with chronic gastrointestinal motor dysfunction. The LLLT protocol used red LED light at a wavelength of 660 nm for 10 min and infrared LED light at a wavelength of 840 nm for 10 min, followed by infrared laser light at a wavelength of 825 nm for 10 min. Effects on the autonomic nervous system were assessed by measuring heart rate variability (HRV) changes. Respiratory Sinus Arrhythmia (RSA) and Root Mean Square of Successive Differences (RMSSD) were used to quantify parasympathetic reactivity; the Baevsky’s Stress Index (SI) reflected sympathetic activity while the ratios SI/RSA and SI/RMSSD were used to show shifts in autonomic dominance. The results indicate that lumbar and sacral neuromodulation using light arrays reduced, whereas stimulation by the laser probes significantly increased parasympathetic activity. The light arrays increased whereas the laser probes significantly decreased sympathetic activity (SI). The entire protocol shifted the autonomic balance toward parasympathetic activity. The comparison of actual vs. sham neuromodulation proved that the change in HRV parameters was due to actual light stimulation and not due to the arrays and probe touching the skin. In conclusion, a single session of LLLT markedly affects autonomic nervous system activity reflected in changes in HRV which is only possible by generating activity in the spinal autonomic nerves. These results warrant a study into the effects of LLLT on restoring autonomic dysfunction in chronic refractory colonic motility disorders.

Сardiorespiratory relationships in people of young age depending on the composite composition of the body

BACKGROUND: The decisive importance of the sympathetic and parasympathetic nervous system in maintaining vegetative homeostasis requires the determination of sensitive non-invasive parameters of multidimensional outpatient monitoring of cardiorespiratory adaptation under various physiological and clinical conditions, taking into account the function of external respiration (FER), compound body composition and heart rate variability (HRV).AIM: To identify concomitant changes in HRV, HR and compound body composition in young people as markers of cardiorespiratory adaptation and rehabilitation.MATERIALS AND METHODS: On the basis of the Kuban State Medical University, a single-centre, interventional, cross-sectional, single-sample, comparative, uncontrolled study of a general group of young people in which respiratory parameters and parameters of the compound body composition were determined. Some individuals in this group additionally underwent Holter monitoring of the electrocardiogram (ECG) at short intervals.RESULTS: In young people, a change in the compound body composition with an increase in total fat mass, visceral and body fat is associated with a decrease in respiratory function (a decrease in the Tiffno index, a decrease in the maximum middle-expiratory flow — MMEF), manifested by a decrease in HRV (according to the TI indicator), the absence of an increase in the autonomic regulation circuit (according to SDNN indicator), a decrease in parasympathetic activity (in terms of rMSSD) and the absence of sympathetic activation (in terms of SDANN). Positive shifts in the form of an increase in trunk muscles, the total amount of water and a decrease in the total fat mass are accompanied by an increase in lung capacity, forced expiratory volume in the first second and a change in HRV with sympathetic (in terms of LF / HF, SDANN) and parasympathetic activation (in terms of rMSSD), an increase in HRV (in terms of TI) and an increase in the autonomic regulation circuit of the vegetative nervous system (in terms of SDNN).CONCLUSION: Accurate and rapid diagnostics of vegetative homeostasis requires a comprehensive correlative analysis of the parameters characterizing HRV in short recordings, the compound composition of the human body and respiratory function.

Fitness, performance, and cardiac autonomic responses to exercise in people with epilepsy

People with epilepsy (PWE) are less fit and have an increased risk of sudden cardiac death. Imbalances within the autonomic nervous system (ANS) are believed to mediate some of those effects. However, results are mostly derived from patients whose seizures are refractory to medical therapy. In this study, an exhaustive bicycle ergometer test was delivered to 25 PWE (19 seizure free in the last 6 months) recruited in a community-based setting and 25 age-, sex-, and BMI-matched healthy controls. During the exercise test a 12-channel ECG was recorded and spirometry was carried out to determine the maximal oxygen uptake (VO2peak) as the gold standard to assess fitness. Before and after exercise, heart rate variability (HRV) and electrodermal activity (EDA) were measured along with an electroencephalogram (EEG). Blood samples were collected to determine anti-seizure drug (ASD) serum levels and physical activity of daily living was evaluated via the International Physical Activity Questionnaire (IPAQ). People with epilepsy and healthy controls were similarly fit and physically active. However, PWE had a lower maximum heart rate, a lower heart rate reserve, and a lower chronotropic index. The ratio between low- to high-frequency HRV changes (LF/HF ratio) was lower in PWE. Two patients with idiopathic genetic epilepsies revealed generalized interictal epileptiform discharges only after, but not before exercise. However, post-exercise EEG measurement was three times longer than pre-exercise and those patients did not report exercise induced seizures in the history. Besides epileptogenesis, anti-seizure medications may also contribute to those autonomic differences.

Heart rate variability (HRV) changes and cortical volume changes in a randomized trial of five weeks of daily HRV biofeedback in younger and older adults

Previous studies indicate that the structure and function of medial prefrontal cortex (PFC) and lateral orbitofrontal cortex (OFC) are associated with heart rate variability (HRV). Typically, this association is assumed to reflect the PFC's role in controlling HRV and emotion regulation, with better prefrontal structural integrity supporting greater HRV and better emotion regulation. However, as a control system, the PFC must monitor and respond to heart rate oscillatory activity. Thus, engaging in regulatory feedback during heart rate oscillatory activity may over time help shape PFC structure, as relevant circuits and connections are modified. In the current study with younger and older adults, we tested whether 5 weeks of daily sessions of biofeedback to increase heart rate oscillations (Osc+ condition) vs. to decrease heart rate oscillations (Osc− condition) affected cortical volume in left OFC and right OFC, two regions particularly associated with HRV in prior studies. The left OFC showed significant differences in volume change across conditions, with Osc+ increasing volume relative to Osc−. The volume changes in left OFC were significantly correlated with changes in mood disturbance. In addition, resting low frequency HRV increased more in the Osc+ than in the Osc− condition. These findings indicate that daily biofeedback sessions regulating heart rate oscillatory activity can shape both resting HRV and the brain circuits that help control HRV and regulate emotion.

Depressive rumination and heart rate variability: A pilot study on the effect of biofeedback on rumination and its physiological concomitants.

ObjectiveRecent studies suggest that lower resting heart rate variability (HRV) is associated with elevated vulnerability to depressive rumination. In this study, we tested whether increases in HRV after HRV-biofeedback training are accompanied by reductions in rumination levels.Materials and methodsSixteen patients suffering from depression completed a 6-week HRV-biofeedback training and fourteen patients completed a control condition in which there was no intervention (waitlist). The training included five sessions per week at home using a smartphone application and an ECG belt. Depressive symptoms and autonomic function at rest and during induced rumination were assessed before and after each of the two conditions. We used a well-established rumination induction task to provoke a state of pervasive rumination while recording various physiological signals simultaneously. Changes in HRV, respiration rate, skin conductance, and pupil diameter were compared between conditions and time points.ResultsA significant correlation was found between resting HRV and rumination levels, both assessed at the first laboratory session (r = -0.43, p < 0.05). Induction of rumination led to an acceleration of heart rate and skin conductance increases. After biofeedback training, resting vagal HRV was increased (p < 0.01) and self-ratings of state anxiety (p < 0.05), rumination (p < 0.05), perceived stress (p < 0.05), and depressive symptoms (QIDS, BDI; both p < 0.05) were decreased. In the control condition, there were no changes in autonomic indices or depressive symptomatology. A significant interaction effect group x time on HRV was observed.ConclusionOur results indicate that a smartphone-based HRV-biofeedback intervention can be applied to improve cardiovagal function and to reduce depressive symptoms including self-rated rumination tendencies.

Heart Rate Variability-An Index of the Efficacy of Complementary Therapies in Irritable Bowel Syndrome: A Systematic Review.

Irritable bowel syndrome (IBS), as a functional and psychosomatic disease, reduces the quality of life and increases the risk of developing mental disorders. Deregulation of the autonomic nervous system (ANS) is one of the main causes of the disease. The objective of the present study was to identify the studies in which measurements of heart rate variability (HRV) were performed before and after therapeutic intervention, and to evaluate the effectiveness of IBS therapy in terms of a reduction of IBS symptoms and changes in autonomic tone. A systematic review of the literature was carried out in accordance with PRISMA standards. Six databases were searched for articles published before 2022: PubMed®, MEDLINE®, EBSCO, Cochrane, Scopus, and Web of Science. Inclusion criteria were experimental design, diagnosis of IBS (medical and/or diagnosis in accordance with the Rome Criteria), non-pharmacological intervention, and HRV measurement before and after the intervention. The quality of the studies was assessed by JBI Critical appraisal. In total, 455 studies were identified, of which, sixwere included in the review. Expected changes in HRV (increase in parasympathetic activity) were observed in four of the six studies (interventions studied: ear acupressure, transcutaneous auricular vagusnerve stimulation, cognitive behavioral therapy with relaxation elements, yoga). In the same studies, therapeutic interventions significantly reduced the symptoms of IBS. The present review indicated that interventions under investigation improve the efficiency of the ANS and reduce the symptoms of IBS. It is advisable to include HRV measurements as a measure of the effectiveness of interventions in IBS therapy, and to assess autonomic changes as a moderator of the effectiveness of IBS therapy.

Vegetative and electrical disorders in women with chronic coronary syndrome depending on the state of bone mineral density

Aim: to determine the features of heart rate variability and electrical changes in the myocardium in women with chronic coronary syndrome, depending on the state of the bone mineral density (BMD). Materials and methods. 121 women with chronic coronary syndrome (CCS): stable exertional angina of II–III functional class (FC) (mean age 68.0 (60.0; 75.0) years) were examined and divided into 3 groups: group 1 − 30 women with ССS and normal BMD; group 2 – 33 women with CCS and osteopenia (OPе); group 3 – 58 women with CCS and osteoporosis (OP). All patients underwent daily ECG monitoring and ultrasound osteodensitometry. Results. In women with CCS and OP, increase in the frequency (by 2.9 times; P &lt; 0.05) and duration (by 2.3 times; P &lt; 0.05) of tachycardia episodes, the frequency of registration of ventricular and supraventricular extrasystole episodes (by 8.1 time and 1.2 times, respectively; P &lt; 0.05) if compared to patients without BMD disorders was found. In women with СCS and OPе there was a tendency to increase in these indicators, which did not reach the level of statistical significance. The presence of BMD disorders in patients with CCS was accompanied with decrease in total HRV activity (RMSSD and HRVT), the development of the predominance of ANS sympathetic domain activity, as evidenced by an increase in LF by 44.3 % at the daytime and 44.0 % at night, decrease in HF 2.3 times during the day and 2.1 times at night in patients with OPe and OP, respectively. According to the correlation analysis data, the presence of correlations between the state of BMD and indicators of electrical and autonomic activity of the myocardium was established. Conclusions. In postmenopausal women with CCS, the severity of autonomic and electrical disorders is associated with the degree of bone disorders and is maximal in osteoporosis.

Association of the Heart Rate Variability Response to Active Standing with the Severity of Calcific Aortic Valve Disease: Novel Insights of a Neurocardiovascular Pathology.

The aim of this work was to obtain insights of the participation of the autonomic nervous system in different stages of calcific aortic valve disease (CAVD) by heart rate variability (HRV) analysis. Studying subjects with no valve impairments and CAVD patients, we also sought to quantify the independent contribution or explanatory capacity of the aortic valve echocardiographic parameters involved in the HRV changes caused by active standing using hierarchical partitioning models to consider other variables or potential confounders. We detected smaller adjustments of the cardiac autonomic response at active standing caused specifically by the aortic valve deterioration. The highest association (i.e., the highest percentage of independent exploratory capacity) was found between the aortic valve area and the active standing changes in the short-term HRV scaling exponent α1 (4.591%). The valve’s maximum pressure gradient echocardiographic parameter was present in most models assessed (in six out of eight models of HRV indices that included a valve parameter as an independent variable). Overall, our study provides insights with a wider perspective to explore and consider CAVD as a neurocardiovascular pathology. This pathology involves autonomic-driven compensatory mechanisms that seem generated by the aortic valve deterioration.

Improvement of pain experience and changes in heart rate variability through music-imaginative pain treatment.

Music-imaginative Pain Treatment (MIPT) is a form of music therapy addressing pain experience and affective attitudes toward pain. It includes two self-composed music pieces: one dedicated to the pain experience (pain music, PM) and the other to healing imagination (healing music, HM). Our non-experimental study addresses patients with chronic somatoform pain disorders participating in MIPT. The goal is to gain insight into the direct effect mechanisms of MIPT by combining outcome measures on both the objective physiological and subjective perception levels. The research questions are directed toward changes in pain experience and heart rate variability and their correlations. Thirty-seven hospitalized patients with chronic or somatoform pain disorders receiving MIPT participated in this study. Demographic data and psychometric measures (Symptom Check List SCL90, Childhood Trauma Questionnaire CTQ) were collected to characterize the sample. Subjective pain experience was measured by McGill Pain Questionnaire (SF-MPQ), and Heart Rate Variability by 24 h-ECG. Data analysis shows a reduction of reported pain from MT1 = 19.1 (SD = 7.3) to MT2 = 10.6 (SD = 8.0) in all dimensions of the SF-MPQ. HRV analyses shows a reduced absolute power during PM and HM, while a relative shift in the autonomic system toward higher vagal activity appears during HM. Significant correlations between HRV and MPQ could not be calculated. Findings are interpreted as a physiological correlate to the psychological processes of the patients. Future studies with more participants, a control-group design, and the integration of medium- and long-term effects are recommended.

Coronary heart disease and depressive disorders, pathogenesis and actual features of the relationship

In the conditions of the existing pandemic, that affects both the physical and psychological health of people, it can be predicted with a high degree of probability an outbreak in mental disorders and stress-associated mental illnesses, including depression. The problem of the relationship between depression and cardiac diseases, in particular coronary heart disease (CHD), has been studied by native and foreign scientists for several decades. Various mechanisms have been found and continue to be studied, indicating that the presence of depression can affect more or less on the course of coronary heart disease and even become a predictor of new cardiac events. Dysfunction of the autonomic nervous system with changes in heart rate variability, hyperactivity of the hypothalamic-pituitary-adrenal axis and associated hypercortisolemia, disorders of serotonergic signal transmission pathways, high aggregation response and increased platelet activity, continuous increase of proinflammatory cytokines ((IL17A, IL6, TNFa and IL12p70) in patients’ plasma – such mechanisms probably underlie the correlation between depression and an increased risk of cardiovascular complications and cardiac death. The review includes some features of depression and its influence on various forms of coronary heart disease, particularly in different age and gender groups. In view of the ongoing COVID-19 pandemic, this theme seems to be relevant and requires targeted study. Probably it is necessary to conduct clinical researches, to create registers for a detailed assessment of the mutual influence of depression and coronary heart disease in existing conditions. Perhaps, the results of such work will contribute not only to the early detection and treatment of depression, but also to the development of new ways in primary and secondary prevention of coronary heart disease and its acute forms.

Prediction of the Occurrence of the Oculocardiac Reflex Based on the Assessment of Heart Rate Variability. An Observational Study

IntroductionOphthalmic surgery is assumed to be safe, but some operations require general anaesthesia which is associated with a number of potential complications. In addition, adverse cardiovascular symptoms, such as severe slowing of the heart rate and, in some cases, cardiac arrest may occur due to the surgical technique. The aim of this study was to determine whether it is possible to predict the occurrence of oculocardiac reflex (OCR) based on heart rate variability (HRV) analysis for autonomic nervous system (ANS) activity assessment measured prior to the induction of anaesthesia and immediately before eyeball traction.MethodsFifty-two adults of both sexes (age range 18–65 years) with American Society of Anesthesiologists (ASA) physical status class 1 and 2 were enrolled in this study. All patients had underwent episcleral buckling under general anaesthesia. High-frequency (HF) changes in HRV are thought to reflect parasympathetic impulse transmission, whereas low-frequency (LF) changes reflect both sympathetic and parasympathetic activity. However, in practice, LF changes can be considered to reflect sympathetic changes. Thus, the LF/HF ratio reflects the actual balance between sympathetic and parasympathetic activity. Based on that, frequency domain HRV parameters from 5-min Holter electrocardiogram recordings before anaesthesia induction and before eyeball traction were used for the analysis. The statistical analysis also included patient age, sex, ASA status and preanaesthesia and premanoeuvre heart rate and blood pressure.ResultsData from 42 patients were analysed. Oculocardiac reflex was observed in 32 patients (76.2%). No difference was found in the analysed parameters between patients with and without oculocardiac reflex. There was no relationship between the incidence of the OCR and the analysed parameters.ConclusionThe prediction of OCR based on initial ANS tone was not possible, and the initial heart rate, blood pressure, age, sex, and ASA status were not helpful for the identification of patients at risk of this reflex.Trial registrationClinicalTrials.gov identifier no.: NCT01714362

Changes in Subjective Time and Self during Meditation.

Simple SummaryMeditation induces an altered state of consciousness, which is often described by meditators as being in the present moment and losing one’s sense of time and self. Few studies have assessed these experiences. We invited 22 experienced meditators to participate in two experimental sessions lasting 20 min each (1) to meditate and (2) to read a story as a control condition. We measured their heart and breathing rates during these two sessions and conducted a metronome task before and after each session. In this task, participants had to group metronome beats into perceptual units, a measure of the duration of the present moment. In comparison to the reading condition, the heart and breathing rates showed a mix of increased as well as decreased bodily activity in the meditation condition. In the meditation condition, participants subjectively perceived their body boundaries less strongly, paid less attention to time, and felt time pass more quickly compared to the control condition. No differences between conditions were apparent for the metronome task. This study is the first to show how the sense of self and time are relatively diminished during meditation.This study examined the effects of meditative states in experienced meditators on present-moment awareness, subjective time, and self-awareness while assessing meditation-induced changes in heart-rate variability and breathing rate. A sample of 22 experienced meditators who practiced meditation techniques stressing awareness of the present moment (average 20 years of practice) filled out subjective scales pertaining to sense of time and the bodily self and accomplished a metronome task as an operationalization of present-moment awareness before and after a 20 min meditation session (experimental condition) and a 20 min reading session (control condition) according to a within-subject design. A mixed pattern of increased sympathetic and parasympathetic activity was found during meditation regarding heart-rate measures. Breathing intervals were prolonged during meditation. Participants perceived their body boundaries as less salient during meditation than while reading the story; they also felt time passed more quickly and they paid less attention to time during meditation. No significant differences between conditions became apparent for the metronome task. This is probably the first quantitative study to show how the experience of time during a meditation session is altered together with the sense of the bodily self.

The relationship between cardiac damage biomarkers and heart rate variability following 60min of running.

Endurance exercise may cause transient alterations in cardiac tissue. The number of studies evaluating the relationship between changes in heart rate variability (HRV) and cardiac biomarkers following an endurance event is limited. We hypothesized that there would be a time-dependent correlation between biomarkers of cardiac damage and the reduction in parasympathetic indices of HRV within 24h after 60min of running in middle-aged recreational runners. The trained, middle-aged runners who participated in this study ran 60min at a half-marathon pace on a treadmill. Blood samples (before and 0, 4, and 24h after the running test) and HRV data (before and 0, 1, 4, and 24h after the running test) were obtained. After running, cardiac biomarkers (total creatine kinase, cardiac isoform of creatine kinase, creatine kinase-index [CK-Index], cardiac troponin [cTnI]) increased significantly, and HRV measures related to parasympathetic nervous system activity decreased significantly; these measures returned to baseline levels within 24h. Finally, there were significant correlations (all p < 0.05) between the change (4h post-running vs. pre-running) in the CK-Index and the changes (post- vs pre-running) in time-domain and nonlinear measures of HRV (r -0.61 to -0.67). In addition, significant correlations (all p < 0.05) were found between the area under the cTnI curve and change (1-h post- and pre-running) in time-domain and nonlinear measures of HRV (r -0.48 to -0.51). The correlation between HRV and cardiac biomarkers indicates that HRV analysis may be an alternative approach to determine the magnitude of cardiac stress after endurance exercises.

Desaturation severity affects OSA-related changes in short-term heart rate variability

Desaturation severity affects OSA-related changes in short-term heart rate variability

Polyunsaturated Fatty Acid EAB-277® Supplementation Improved Heart Rate Variability and Clinical Signs in Tracheal Collapse Dogs.

Canine tracheal collapse is a progressive disease in small breed dogs resulting from chronic inflammation of the tracheal mucosal lining. Polyunsaturated fatty acid EAB-277® is one of the nutraceuticals that can alleviate inflammation and oxidative stress. Heart rate variability (HRV) is a prognostic tool related to sympathovagal balance and oxidative stress level, which is widely used with cardiorespiratory diseases. However, the effect of EAB-277® on HRV in tracheal collapse dogs has rarely been investigated. In this study, 26 tracheal collapse dogs were divided into two groups. In the control group, the dogs received the standard treatment, whereas the dogs in the EAB-277® group received standard treatment combined with EAB-277®. After being treated for 5 weeks, changes in radiographic findings, blood profiles, serum malondialdehyde, inflammatory markers, and HRV were evaluated. This study found that clinical signs were improved in both groups (p < 0.05). However, serum malondialdehyde (MDA), Interleukin-6 (IL-6), and Tumor necrosis factor-alpha (TNF-α) were decreased only in the EAB-277® group after treatment for five weeks (p < 0.05) and the mean percent change of MDA, IL-6, and TNF-α at week five compared to baseline in the EAB-277® group was greater than in the control group (p < 0.05). Additionally, greater sympathovagal imbalance indicated by decreased standard deviation of all normal R-R intervals (SDNN) and standard deviation of the averaged R-R intervals for all 5-minutes segments (SDANN) was found in the control group at week five compared to baseline (P < 0.05), whereas EAB-277® improved SDNN and SDANN and decreased low frequency/high-frequency component (LF/HF ratio) after being treated for five weeks (P < 0.05). This study demonstrates that EAB-277® improves clinical signs and attenuates HRV impairment by reducing oxidative stress and inflammation in tracheal collapse dogs.

Cross-sectional and longitudinal associations of styrene and ethylbenzene exposure with heart rate variability alternation among urban adult population in China

Styrene and ethylbenzene (S/EB) are the monomers of polystyrene (PS) and polyethylene (PE), respectively, and have been identified as significant hazardous air pollutants by the U.S. Environmental Protection Agency. However, the adverse effects of S/EB on human health, especially cardiovascular health, have not been well established. Urinary biomarker of S/EB exposure and heart rate variability (HRV) were measured in urban adults from the Wuhan-Zhuhai cohort and were repeated after 3-year and 6-year follow-ups. Linear mixed models were used to estimate associations of S/EB exposure biomarker with HRV and longitudinal additional annual change of HRV. The mediating role of transforming growth factor (TGF)-β1 was tested by using mediation analysis. A total of 2842 general adults were included at baseline analysis, and 4748 observations were included in the repeated measurement study. In the cross-sectional analysis, each 1% increment in urinary S/EB exposure biomarker was significantly associated with a 0.106 % (95 % CI: −0.160, −0.052), 0.109 % (−0.169, −0.049), 0.099 % (−0.145, −0.053), 0.040 % (−0.060, −0.020), and 0.031 % (−0.054, −0.007) decrement in low frequency (LF), high frequency (HF), total power (TP), standard deviation of all normal-to-normal intervals (SDNN), and square root of the mean squared difference between adjacent normal-to-normal interval, respectively. Smoking status modified the relationships of urinary S/EB exposure biomarker with TP and SDNN. TGF-β1 mediated 3.09–5.16 % of the association between urinary S/EB biomarker and lower HRV. The follow-up analyses detected a negative association between urinary S/EB exposure biomarker and the additional annual change of LF (β: −0.016; 95 % CI: −0.028, −0.004), HF (−0.014; −0.026, −0.001), and TP (−0.011; −0.021, −0.001). Our findings demonstrated that S/EB exposure was associated with HRV reduction among the general urban adults and the TGF-β pathway may play a part of the mediating role in this association.