Changes In Heart Rate Variability Research Articles

The Neuroimmune Response to Surgery - An Exploratory Study of Trauma-Induced Changes in Innate Immunity and Heart Rate Variability.

Surgery triggers a systemic inflammatory response that ultimately impacts the brain and associates with long-term cognitive impairment. Adequate regulation of this immune surge is pivotal for a successful surgical recovery. We explored the temporal immune response in a surgical cohort and its associations with neuroimmune regulatory pathways and cognition, in keeping with the growing body of evidence pointing towards the brain as a regulator of peripheral inflammation. Brain-to-immune communication acts through cellular, humoral and neural pathways. In this context, the vagal nerve and the cholinergic anti-inflammatory pathway (CAP) have been shown to modify peripheral immune cell activity in both acute and chronic inflammatory conditions. However, the relevance of neuroimmune regulatory mechanisms following a surgical trauma is not yet elucidated. Twenty-five male patients undergoing elective laparoscopic abdominal surgery were included in this observational prospective study. Serial blood samples with extensive immune characterization, assessments of heart rate variability (HRV) and cognitive tests were performed before surgery and continuing up to 6 months post-surgery. Temporal immune responses revealed biphasic reaction patterns with most pronounced changes at 5 hours after skin incision and 14 days following surgery. Estimations of cardiac vagal nerve activity through HRV recordings revealed great individual variations depending on the pre-operative HRV baseline. A principal component analysis displayed distinct differences in systemic inflammatory biomarker trajectories primarily based on pre-operative HRV, with potiential consequences for long-term surgical outcomes. In conclusion, individual pre-operative HRV generates differential response patterns that associate with distinct inflammatory trajectories following surgery. Long-term surgical outcomes need to be examined further in larger studies with mixed gender cohorts.

복합운동이 직장인 여성들의 HRV 및 APG에 미치는 영향

This study compares and analyzes changes in HRV(heart rate variability), and APG(vascular age) through spinning exercise and Zumba dance for working women, and how they show stress and physical changes through exercise. A study was conducted to find out, and the following conclusions were obtained. As a result of performing a compound exercise of spinning and Zumba for 8 weeks, the HRV (heart rate variability) change showed a significant difference in the exercise group, a significant difference in the measurement period, and an interaction effect between the period×group. APG(vascular age) change showed a significant difference in the exercise group, a significant difference between the groups, and an interaction effect was found between the time×groups. As a result of performing the spinning exercise and Zumba dance for a total of 8 weeks, HRV(heart rate variability), and APG(vascular age) were reduced. It is expected that it will be used as one of the positive exercise programs in the social structure where working women can not improve and maintain their health on a regular basis.

Exposures to low-levels of fine particulate matter are associated with acute changes in heart rate variability, cardiac repolarization, and circulating blood lipids in coronary artery disease patients

Exposure to air pollution is a major risk factor for cardiovascular disease, disease risk factors, and mortality. Specifically, particulate matter (PM), and to some extent ozone, are contributors to these effects. In addition, exposures to these pollutants may be especially dangerous for susceptible populations. In this repeated-visit panel study, cardiovascular markers were collected from thirteen male participants with stable coronary artery disease. For 0–4 days prior to the health measurement collections, daily concentrations of fine PM (PM2.5) and ozone were obtained from local central monitoring stations located near the participant's homes. Then, single (PM2.5) and two-pollutant (PM2.5 and ozone) models were used to assess whether there were short-term changes in cardiovascular health markers. Per interquartile range increase in PM2.5, there were decrements in several heart rate variability metrics, including the standard deviation of the normal-to-normal intervals (lag 3, -5.8%, 95% confidence interval (CI) = −11.5, 0.3) and root-mean squared of successive differences (five day moving average, −8.1%, 95% CI = −15.0, −0.7). In addition, increases in PM2.5 were also associated with changes in P complexity (lag 1, 4.4%, 95% CI = 0.5, 8.5), QRS complexity (lag 1, 4.9%, 95% CI = 1.4, 8.5), total cholesterol (five day moving average, −2.1%, 95% CI = −4.1, −0.1), and high-density lipoprotein cholesterol (lag 2, -1.6%, 95% CI = −3.1, −0.1). Comparisons to our previously published work on ozone were conducted. We found that ozone affected inflammation and endothelial function, whereas PM2.5 influenced heart rate variability, repolarization, and lipids. All the health changes from these two studies were found at concentrations below the United States Environmental Protection Agency's National Ambient Air Quality Standards. Our results imply clear differences in the cardiovascular outcomes observed with exposure to the two ubiquitous air pollutants PM2.5 and ozone; this observation suggests different mechanisms of toxicity for these exposures.

Predictive Capacity of Beat-to-Beat Blood Pressure Variability for Cardioautonomic and Vascular Dysfunction in Early Metabolic Challenge

Diabetic patients present established cardiovascular disease at the onset of diagnostic metabolic symptoms. While premature autonomic and vascular deterioration considered risk factors for major cardiovascular complications of diabetes, present in initial stages of metabolic impairment, their early detection remains a significant challenge impeding timely intervention. In the present study, we examine the utility of beat-to-beat blood pressure variability (BPV) parameters in capturing subtle changes in cardiac autonomic and vascular control distinguishing between various risk categories, independent of the average BP. A rat model of mild hypercaloric (HC) intake was used to represent the insidious cardiovascular changes associated with early metabolic impairment. Invasive hemodynamics were used to collect beat-to-beat BP time series in rats of either sex with different durations of exposure to the HC diet. Linear (standard deviation and coefficient of variation) and nonlinear (approximate entropy, ApEn, and self-correlation of detrended fluctuation analysis, α) BPV parameters were calculated to assess the impact of early metabolic impairment across sexes and feeding durations. HC-fed male, but not female, rats developed increased fat:lean ratio as well as hyperinsulinemia. Unlike linear parameters, multivariate analysis showed that HC-fed rats possessed lower ApEn and higher α, consistent with early changes in heart rate variability and blunting of parasympathetic baroreceptor sensitivity, particularly in males. Moreover, logistic regression demonstrated the superiority of nonlinear parameters of diastolic BPV in predicting a prediabetic disease state. Our findings support the use of nonlinear beat-to-beat BPV for early detection of cardiovascular derangements in the initial stages of metabolic impairment.

The Effects of a Peaking Protocol on Heart Rate Variability and its Predictive Associations with Wilks Coefficient in Competitive Powerlifters

Powerlifting competition is comprised of three barbell lifts: squat, bench press, and deadlift that are all completed in a single day and summed together, ultimately normalized to the lifter’s body weight via the Wilks Coefficient. This figure is then subsequently employed to determine the “best” athlete in that meet. During the competition preparation, powerlifters often undergo peaking protocols which include physiologically taxing overreach and low-volume, recovery-focused taper phases to collectively induce super-compensatory strength adaptations. Heart rate variability (HRV) has emerged as an easily accessible, user-friendly biomarker for autonomic nervous system-associated fatigue and readiness. Therefore, the purpose of this observational study was to investigate the potential impact of a peaking protocol on fatigue/readiness via HRV measurements and its possible relationship with competitive powerlifting performance. Daily measurements of HRV were taken, each morning, using the HRV4Trainning smartphone application by nineteen competitive powerlifters (26.16±4.56 years) from 14-days prior to a peaking protocol, throughout individual peaking phases, on meet day, and 14-days following competition. A quadratic regression was used to determine the predictability of HRV measurements and powerlifting performance. The change in HRV from competition day to baseline was found to be a significant predictor of Wilks coefficient (p=0.038,

Transcutaneous Cervical Vagus Nerve Stimulation Induces Changes in the Electroencephalogram and Heart Rate Variability of Healthy Dogs, a Pilot Study.

Transcutaneous cervical vagus nerve stimulation (tcVNS) has been used to treat epilepsy in people and dogs. Objective electroencephalographic (EEG) and heart rate variability (HRV) data associated with tcVNS have been reported in people. The question remained whether EEG and electrocardiography (ECG) would detect changes in brain activity and HRV, respectively, after tcVNS in dogs. Simultaneous EEG and Holter recordings, from 6 client-owned healthy dogs were compared for differences pre- and post- tcVNS in frequency band power analysis (EEG) and HRV. The feasibility and tolerance of the patients to the tcVNS were also noted. In a general linear mixed model, the average power per channel per frequency band was found to be significantly different pre- and post-stimulation in the theta (p = 0.02) and alpha bands (p = 0.04). The pooled power spectral analysis detected a significant decrease in the alpha (p < 0.01), theta (p = 0.01) and beta (p = 0.035) frequencies post-stimulation. No significant interaction was observed between dog, attitude, and stimulation in the multivariate model, neither within the same dog nor between individuals. There was a significant increase in the HRV measured by the standard deviation of the inter-beat (SDNN) index (p < 0.01) and a decrease in mean heart rate (p < 0.01) after tcVNS. The tcVNS was found to be well-tolerated. The results of this pilot study suggest that EEG and ECG can detect changes in brain activity and HRV associated with tcVNS in healthy dogs. Larger randomized controlled studies are required to confirm the results of this study and to assess tcVNS potential therapeutic value.

Temporal Analysis of Sequential Changes in Heart Rate Variability During Non-hypotensive Hypovolemia.

Haemorrhage is associated with changes in the cardiac autonomic drive which begins during early stages of mild haemorrhage. The knowledge of chronology of the autonomic changes at smaller timescale during the period of haemorrhage can help identify the primary autonomic parameter which signals the institution of cardiovascular reflex mechanisms. To evaluate the heart rate variability in 2-min sequential segments with one minute overlap during and after the period of mild haemorrhage (450 ml) using blood donation as a model of acute blood loss. 47 male blood donors who had volunteered for blood donation were recruited for the study. Continuous lead II ECG was recorded before the start of the blood donation (5 min), during the period of the blood donation (~ 5-7 min) and after blood donation (5 min). The parasympathetic and sympathetic drive to heart was estimated by measures of heart rate variability in time and frequency domain. A significant decrease in the parameters assessing parasympathetic drive i.e., normalised High frequency (HFn) and NN50 (Number of pairs of adjacent NN intervals differing by more than 50 ms) and pNN50 (NN50 divided by the total number of all NN Intervals) was observed during blood donation at 3-5 min, as compared to baseline. An increase in parameters associated with sympathetic drive i.e., normalised low frequency (LFn) was observed only in the post donation period at 2-3 min. A significant rise in LF/HF ratio which is a marker of sympatho vagal balance was observed at 4-5 min during blood donation when compared to baseline. The initial cardiac autonomic change during mild haemorrhage is withdrawal of parasympathetic drive, followed by an increase in sympathetic tone which occurs much later.

Longitudinal Changes in Arterial Stiffness and Heart Rate Variability in Youth-Onset Type 1 Versus Type 2 Diabetes: The SEARCH for Diabetes in Youth Study.

We compared arterial stiffness and heart rate variability (HRV) over time by diabetes type and determined the risk factors associated with worsening arterial stiffness and HRV in young adults with youth-onset diabetes. Arterial stiffness (pulse wave velocity, augmentation index) and six indices of heart rate variability were measured twice, 4.5 years apart, among participants with either youth-onset type 1 or type 2 diabetes in the SEARCH for Diabetes in Youth study. Multivariable linear regression models were used to assess risk factors associated with arterial stiffness and HRV at follow-up. Of 1,159 participants studied, 949 had type 1 diabetes (mean age 17.1 ± 4.7 years, 60.3% non-Hispanic White, 55% female) and 210 had type 2 diabetes (mean age 22.1 ± 3.5 years, 23.8% non-Hispanic White, 71% female) at initial assessment when diabetes duration was 7.9 years (both groups). Participants with type 2 versus type 1 diabetes had greater arterial stiffness and more abnormalities in HRV at initial and follow-up assessment and a greater change over time (all P < 0.05). Risk factors associated with worse arterial stiffness and HRV at follow-up in both types of diabetes included higher blood pressure, hemoglobin A1c, waist circumference, and triglycerides over time and longer diabetes duration. Arterial stiffness and HRV worsened over time with greater changes among participants with type 2 versus type 1 diabetes and among those with features of the metabolic syndrome. The risk factor profile documents potentially modifiable pathways to prevent or limit cardiovascular complications in young adults with youth-onset diabetes.

Changes in tendon blood circulation and heart rate variability after intermittent compression to patellar and Achilles tendons

BackgroundThe purpose of this study was to compare changes in tendon blood circulation and heart rate variability after intermittent compression to the patellar and Achilles tendons. MethodsBefore the intermittent compression to tendons (3 min) and the recovery period (40 min), the blood volume and oxygen saturation of the patellar and Achilles tendons were measured using red laser lights. In addition, heart rate and ratio of low-frequency to high-frequency components of heart rate variability were measured. FindingsBlood volume and oxygen saturation of patellar and Achilles tendons significantly increased after intermittent compression stimulation (both p ≤ 0.001). There were no differences in increases of blood volume (p = 0.575) and oxygen saturation (p = 0.055) between patellar and Achilles tendons. For both tendons treatments, heart rate (p = 0.698) and ratio of low-frequency to high-frequency components of heart rate variability (p = 0.518) did not change during the experimental period. In addition, the change in blood volume for Achilles tendon was significantly correlated with that in heart rate but not ratio of low-frequency to high-frequency components of heart rate variability, whereas the change in blood volume for patellar tendon was not significantly correlated with that in the heart rate or ratio of low-frequency to high-frequency components of heart rate variability,. InterpretationThese results suggest that intermittent compression-induced changes in blood circulation were similar between patellar and Achilles tendons. In addition, the increase in blood volume after intermittent compression stimulation in the Achilles tendon would be related to the increased metabolism of the tendon.

Systemic application of the transient receptor potential vanilloid-type 4 antagonist GSK2193874 induces tail vasodilation in a mouse model of thermoregulation.

In humans, skin is a primary thermoregulatory organ, with vasodilation leading to rapid body cooling, whereas in Rodentia the tail performs an analogous function. Many thermodetection mechanisms are likely to be involved including transient receptor potential vanilloid-type 4 (TRPV4), an ion channel with thermosensitive properties. Previous studies have shown that TRPV4 is a vasodilator by local action in blood vessels, so here, we investigated whether constitutive TRPV4 activity affects Mus muscularis tail vascular tone and thermoregulation. We measured tail blood flow by pressure plethysmography in lightly sedated M. muscularis (CD1 strain) at a range of ambient temperatures, with and without intraperitoneal administration of the blood–brain barrier crossing TRPV4 antagonist GSK2193874. We also measured heart rate (HR) and blood pressure. As expected for a thermoregulatory organ, we found that tail blood flow increased with temperature. However, unexpectedly, we found that GSK2193874 increased tail blood flow at all temperatures, and we observed changes in HR variability. Since local TRPV4 activation causes vasodilation that would increase tail blood flow, these data suggest that increases in tail blood flow resulting from the TRPV4 antagonist may arise from a site other than the blood vessels themselves, perhaps in central cardiovascular control centres.

Assessing the interrelation between oestrogen receptor status, heart rate variability and serum nitric oxide in breast cancer patients: Understanding their prognostic relevance.

e12564 Background: Heart Rate Variability (HRV) is a non-invasive procedure to assess cardiac functions and provides an index of autonomic function that intricately controls vascular tone. Studying the alteration in HRV with agents producing oxidative stress will provide useful information about disease progression. Lower HRV indicates low level of Parasympathetic Nervous System activation and dysregulation of cardiac functions. Elements of tumour microenvironment like prostaglandin E2, oestrogen and hypoxia stimulate nitric oxide (NO) production which reacts with free radicals released by tumour tissue forming oxidising agents. NO enhances oxidative stress causing vascular dysfunction. Very few studies have reported an interrelationship between NO and HRV parameters in breast cancer. The aim of the study is to verify the relation between HRV and serum NO levels in ER+ and ER- breast cancer groups. Methods: Study design: Analytical, Cross sectional. Sample Size: 135 women above 20 years of age with and without breast cancer. 69 women with histologically proven breast cancer in different stages and 66 women who were healthy age matched controls were included. Oestrogen Receptor (ER) status was obtained from clinical records. Out of 69 women with breast cancer, 31 were ER- with 15 in stage 1 and 16 in stage 2. 38 women were ER+ with 5 in stage 2 and 33 in stage 3. Serum NO was measured using colorimetry. Heart Rate Variability was measured from lead II ECG using Power Lab 15T and lab chart software. Serum NO levels and HRV parameters were compared between ER groups. Results: ER+ women had higher HRV with parasympathetic predominance compared to ER- with p&lt;0.001. ER+ women also had higher serum NO levels compared to ER- group with p&lt;0.001. Though no direct correlation was noticed between NO and HRV, multiple analysis of variance showed significant (p&lt;0.001) difference of all values across the groups. irrespective of menopausal status. Conclusions: A significant difference was observed in HRV of ER+ and ER- women with breast cancer. Most ER+ women were in stage 3 with significantly higher NO levels. Serum NO is expected to be the factor most responsible for HRV changes particularly in stage 3/ER+. Parasympathetic predominance seen in ER+ women possibly is due to high NO levels.[Table: see text]

345-OR: Longitudinal Changes in Arterial Stiffness and Heart Rate Variability in Youth-Onset Type 1 vs. Type 2 Diabetes

Limited data exist examining arterial stiffness and heart rate variability (HRV) over time in young adults with youth-onset type 1 (T1D) and type 2 diabetes (T2D) . We compared arterial stiffness and HRV over time and by diabetes type and determined the risk factors associated with worsening arterial stiffness and HRV. Arterial stiffness (pulse wave velocity, augmentation index) and HRV (SDNN and PNN50) were measured twice (∼ 5 years apart) in the SEARCH for Diabetes in Youth Study. Linear regression models assessed risk factors overtime and with arterial stiffness and HRV at follow-up. Of 1159 participants studied, 949 had T1D (mean age 17.1 ± 4.7 years, 60.3% non-Hispanic White, 55% female) and 2had T2D (mean age 22.1 ± 3.5 years, 23.8% non-Hispanic White, 71% female) at initial assessment when diabetes duration was 7.9 years (both groups) . Participants with T2D vs. T1D had greater arterial stiffness and more abnormalities in HRV at initial and follow-up assessments (Figure) .For AIx and PNN50 T2D compared to T1D had a greater change over time (p&amp;lt;0.05) . Risk factors associated with worse arterial stiffness and HRV at follow-up in both T1D and T2D included higher BP, HbA1c, waist circumference, and triglycerides overtime, and longer diabetes duration. Arterial stiffness and HRV worsened over time with greater changes among those with T2D and features of the metabolic syndrome regardless of diabetes type. Disclosure A.S. Shah: None. R. Dagostino: Consultant; Aetion, Inc., AstraZeneca, Biogen, Bristol-Myers Squibb Company, Daiichi Sankyo, Merck &amp; Co., Inc. L.M. Dolan: None. D. Dabelea: None. G. Imperatore: None. A.K. Mottl: Advisory Panel; Bayer AG. Board Member; Bayer AG. Research Support; Alexion Pharmaceuticals, Inc., Aurinia, Bayer AG, Boehringer Ingelheim International GmbH, Pfizer Inc. E. Lustigova: None. C. Pihoker: None. S.M. Marcovina: None. E.M. Urbina: Advisory Panel; Astellas Pharma Inc. Funding NIH and CDC

The Influence of Physical Exercise, Stress and Body Composition on Autonomic Nervous System: A Narrative Review

The heart rate variability (HRV) changes under different situations such as physical exercise, stress and in obese/ overweight subjects. It is considered a noninvasive marker of autonomic nervous system function. The aim of this narrative review was to discuss the relationship between HRV and physical exercise. Moreover, we will make an overview about HRV and stress, and HRV and body composition. There are a large number of studies dealing with HRV, however, few of them explain relationship between HRV and physical exercise, stress and body composition. HRV has proved to be a valuable tool to investigate the sympathetic and parasympathetic function of the ANS. Nonlinear parameters can be used to analyze the health of the subjects and is also used to investigate the stress and the physical exercise level. Despite the underlying mechanisms remain to be elucidated, these finding can be used as a starting point to determine a non-invasive index of cardiac wellness for clinical and nutritional application. Thus, physiological feedback via monitoring HRV would prove useful for addressing the individual’s present capability, be it during selection processes or returning to duty following injury or illness but should not be used to diagnose any pathological conditions.

TWO-YEAR RESPONSES OF HEART RATE AND HEART RATE VARIABILITY TO FIRST OCCUPATIONAL LEAD EXPOSURE

Objective: Because of the falling lead exposure, the literature relating autonomous nervous function to blood lead has limited relevance. Design and method: In the longitudinal Study for Promotion of Health in Recycling Lead (URL: https://www.clinicaltrials.gov; Unique identifier: NCT02243904), we recorded the 2-year responses of heart rate, heart rate variability (Cardiax, International Medical Equipment Developing, Budapest, Hungary), and median nerve conduction velocity (Brevio, NeuMed, West Trenton, NJ), a routine test in occupational medicine, to first lead exposure in 195 newly hired workers (91.3% men; mean age, 27.8 years). High- and low-frequency heart rate variability power and orthostatic heart rate variability responses were derived from 5-minute eletrocardiograms in the supine and standing positions by Fourier transform and autoregression. Blood lead was determined by inductively coupled plasma mass spectrometry. Results: From baseline to follow-up, blood lead increased from 4.22 to 14.1 ug/dL and supine/standing HR from 63.6/75.5 to 67.1/78.8 beats per minute. In analyses stratified by fourths of blood lead changes, trends in heart rate and Fourier/autoregressive heart rate variability did not reveal a dose-response curve (0.074&lt; = P&lt; = 0.98). In multivariable-adjusted mixed models, heart rate, Fourier/autoregressive heart rate variability, and nerve conduction velocity changes were unrelated to blood lead except for a weak inverse association between supine heart rate and blood lead changes (-0.55%; P = 0.029). The expected associations between heart rate variability and heart rate changes were preserved with no differences at baseline/follow-up. Analyses ichotomised by baseline median blood lead or cumulative blood lead index (4.30 ug/dL or 32.1 ug/dL × year) suggested an heart rate variability increase versus decrease in the low versus high baseline exposure group. Conclusions: Thus, a &gt; 3-fold blood lead increment did not affect autonomous neural function as captured by heart rate variability.

The Comparative Effect of Reduced Mindfulness-Based Stress on Heart Rate Variability among Patients with Breast Cancer.

Heart rate variability (HRV) is a powerful tool for observing interactions between the sympathetic and parasympathetic nervous systems. This study evaluated HRV during a mindfulness-based stress reduction (MBSR) program among women with breast cancer after receiving treatment. A quasi-experimental, nonrandomized design was used. Patients were allocated to usual care (n = 25) and MBSR (n = 25) groups. HRV was measured using recognized methods to assess the autonomic nervous system. Two-way ANOVA and t-tests were used to examine HRV changes between and within groups, respectively. A significant interaction effect of time with group was observed on heart rate (F (1, 96) = 4.92, p = 0.029, η2 = 0.049). A significant difference was also observed within the MBSR group preintervention and postintervention with regard to heart rate (t (24) = −3.80, p = 0.001), standard deviation of the RR interval (t (24) = 5.40, p < 0.001), root-mean-square difference in the RR interval (t (24) = 2.23, p = 0.035), and high-frequency power (t (24) = 7.73, p < 0.001). Large effect sizes for heart rate and SDNN of 0.94 and 0.85, respectively, were observed between the MBSR and usual care groups. This study provides preliminary evidence that an MBSR program may be clinically useful for facilitating parasympathetic activity associated with feelings of relaxation in treated breast cancer survivors.

Changes in heart rate variability during cognitive behavior therapy in depressed post-cardiac surgery patients: randomized controlled study

Changes in heart rate variability during cognitive behavior therapy in depressed post-cardiac surgery patients: randomized controlled study

Heart rate variability and meditation: a meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background Meditation can induce changes in autonomic balance, which can benefit cardiovascular health. The present meta-analysis evaluated changes in heart rate variability (HRV) in meditators. Methods PubMed and Embase were searched for primary prospective studies using the search terms ‘heart rate variability’ and ‘meditation’ until January 18th, 2019. The statistical significance of the difference between subgroups is evaluated by the standardized mean difference (SMD), 95% confidence interval (CI), and P-value. I2 value was used to assess the statistical heterogeneity between the included studies. Results Twenty-one studies involving 538 meditators (experienced= 209, beginners= 329) and 334 controls (mean age= 40.61, 35% male) were included. Regarding time-domain indices, no statistically significant differences were observed when assessing HRV between i) meditators versus controls (SMD= -0.17; 95% CI: [-0.50, 0.17]; p= 0.30; I2= 0%), ii) pre- versus post-meditation (SMD= -0.41; 95% CI: [-1.10, 0.28]; p= 0.25; I2= 80%) or iii) at baseline versus during meditation (SMD= -0.40; 95% CI: [-0.94, 0.14]; p= 0.14; I2= 72%). Pertaining to frequency-domain indices, analysis of low frequency (LF), normalized low frequency (LFnu) and high frequency (HF) between i) meditators versus controls, ii) at baseline versus post-meditation and iii) at baseline versus during meditation yet again did not show any variations. Seven studies assessed normalized high frequency (HFnu) at baseline versus during meditation collectively demonstrated a significantly higher HFnu during meditation in beginners with notable heterogeneity (SMD= 1.29; 95% CI: [0.09, 2.49]; p= 0.04; I2= 95). Moreover, LF/HF was evaluated by seven studies at baseline versus during meditation. Both meta-analysis (SMD= 0.76; 95% CI: [-0.17, 1.69]; p= 0.11; I2= 94%) as well as subset analysis of experienced meditators (SMD= -0.46; 95% CI: [-0.88, -0.03]; p= 0.03; I2= 0%) revealed a significantly lower LF/HF at baseline. Conclusions Short-term changes in HRV indices were observed during meditation, but there is limited evidence for significant long-term effects.

Different exercise training modalities similarly improve heart rate variability in sedentary middle-aged adults: the FIT-AGEING randomized controlled trial

PurposeThis study aimed to investigate the influence of different exercise training modalities on heart rate variability (HRV) in sedentary middle-aged adults; and to study whether changes in health-related outcomes (i.e., body composition and cardiometabolic risk) are associated with those hypothetical HRV changes in sedentary middle-aged adults.MethodsA total of 66 middle-aged adults (53.6 ± 4.4 years old; 50% women) were enrolled in the FIT-AGEING study. We conducted a 12-week randomized controlled trial. The participants were randomly assigned to 4 groups: (a) a control group (no exercise); (b) a physical activity recommendation from the World Health Organization group (PAR); (c) a high-intensity interval training group (HIIT); and (d) a high-intensity interval training group adding whole-body electromyostimulation (HIIT + EMS).ResultsAll exercise training modalities induced changes in HRV parameters (all P ≤ 0.001) without statistical differences between them (all P > 0.05). We found associations between changes in body composition and cardiometabolic risk and exercise-related changes in HRV.ConclusionOur results suggest that different exercise interventions (i.e., PAR, HIIT and HIIT + EMS) induced an enhancement of HRV in sedentary middle-aged adults. Our findings support the notion that exercise-related changes in HRV are associated with changes in body composition and cardiometabolic risk after the intervention programClinical trial registryNCT03334357 (ClinicalTrials.gov). November 7, 2017 retrospectively registered.

Oral appliances reduce masticatory muscle activity-sleep bruxism metrics independently of changes in heart rate variability.

Sleep bruxism (SB) is associated with physiological activities including sympathetic autonomic system dominance and sleep micro-arousal. While oral appliances (OA) are used to prevent SB harmful effects, the influence of OAs physiological mechanisms during sleep is unknown. The aim of this study is to assess whether heart rate variability (HRV) changes, as a marker of autonomic nervous system activity, would be associated with the OA mechanism of action on SB using occlusal splint (OS) and mandibular advancement splint (MAS). A retrospective analysis, from data previously collected in 21 participants with SB (25.6 ± 4.5years) with polysomnographic recordings, was done. HRV data were compared between a reference night (no-device) and ones during which OS or MAS was used in a crossover study design. Rhythmic masticatory muscle activity (RMMA) index was compared between nights. HRV was evaluated using autoregressive model analysis for three sections: baseline (distance from RMMA), immediately before, and after RMMA period. A significant reduction in RMMA index, when wearing OA during sleep, was observed (P < 0.01), but was not associated with HRV parameters change. HRV significantly changed after RMMA onset for nights with OA during non-REM sleep in comparison with baseline (P < 0.02). The usage of OAs for SB participants reduced RMMA, but most likely independently of changes in HRV linked to the mechanism associated with SB genesis. Wearing OA seems to reduce grinding noise and protect from dental injuries but does not seem to influence SB genesis.

Parent and child self- and co-regulation during pediatric venipuncture: Exploring heart rate variability and the effects of a mindfulness intervention.

Needle procedures are common throughout childhood and often elicit distress in children and parents. Heart rate variability (HRV), as an index of emotion regulation, can inform both self-regulatory and co-regulatory processes. Mindfulness may serve to regulate distress; however, no research has studied mindfulness or parent and child regulatory responding concurrently during venipuncture. Stemming from a randomized controlled trial investigating a mindfulness intervention, this study sought to describe regulatory responding (via HRV) throughout pediatric venipuncture and the role of cognitive-affective factors (mindfulness, parent anxiety, catastrophizing) in 61 parent-child dyads (7-12 years). We examined (1) patterns of parent and child HRV throughout venipuncture and whether a brief, randomly assigned audio-guided mindfulness versus control exercise affected this pattern and (2) the extent to which changes in parent and child HRV were synchronized throughout venipuncture, and whether parent catastrophizing and anxiety moderated this association. HRV differed as a function of procedural phase. Practicing the mindfulness versus control exercise did not consistently affect HRV in dyads. Positive synchrony was observed during the end of the intervention in dyads with high parental catastrophizing. Otherwise, a pattern of nonsynchrony emerged. Results provide foundational knowledge regarding children's internal (self) and external (parent) regulation mechanisms. RCT registration: NCT03941717.