Root Mean Square Of Successive Differences Research Articles

Characterizing the effect of incrementally increasing dry bulb temperature on linear and nonlinear measures of heart rate variability in nonpregnant, mid-gestation, and late-gestation sows.

Characterizing the sow physiological response to an increased heat load is essential for effective heat stress mitigation. The study objective was to characterize the effects of a 400-min heating episode on sow heart rate variability (HRV) at different reproductive stages. HRV is a commonly used noninvasive proxy measure of autonomic function. Twenty-seven sows were enrolled in the study according to their gestation stage at time of selection: 1) nonpregnant (NP; n = 7), 2) mid-gestation (MID; 57.3±11.8 d gestation; n = 11), and 3) late-gestation (LATE; 98.8±4.9 d gestation; n = 8). The HRV data utilized in the study were collected from each pig as the dry bulb temperature in the room increased incrementally from 19.84±2.15 °C to 35.54±0.43 °C (range: 17.1-37.5 °C) over a 400-min period. After data collection, one 5-min set of continuous heart rate data were identified per pig for each of nine temperature intervals (19-20.99, 21-22.99, 23-24.99, 25-26.99, 27-28.99, 29-30.99, 31-32.99, 33-34.99, and 35-36.99 °C). Mean inter-beat interval length (RR), standard deviation of r-r intervals (SDNN), root mean square of successive differences (RMSSD), high frequency spectral power (HF), sample entropy (SampEn), short-term detrended fluctuation analysis (DFAα1), and three measures (%REC, DET, LMEAN) derived from recurrence quantification analysis were calculated for each data set. All data were analyzed using the PROC GLIMMIX procedure in SAS 9.4. Overall, LATE sows exhibited lower RR than NP sows (P < 0.01). The standard deviation of r-r intervals and RMSSD differed between each group (P < 0.01), with LATE sows exhibiting the lowest SDNN and RMSSD and NP sows exhibiting the greatest SDNN and RMSSD. Late-gestation sows exhibited lower HF than both MID and NP sows (P < 0.0001), greater DFA values than NP sows (P = 0.05), and greater DET compared to MID sows (P = 0.001). Late-gestation also sows exhibited greater %REC and LMEAN compared to MID (P < 0.01) and NP sows (all P < 0.01). In conclusion, LATE sows exhibited indicators of greater autonomic stress throughout the heating period compared to MID and NP sows. However, temperature by treatment interactions were not detected as dry bulb increased. Future studies are needed to fully elucidate the effect of gestational stage and increasing dry bulb temperature on sow HRV.

Study of heart rate variability to assess autonomic dysfunction in patients with chronic obstructive pulmonary disease of a tertiary care hospital of West Bengal: A cross-sectional comparative study

Background: Chronic obstructive pulmonary disease (COPD) is one of the major causes of morbidity and mortality throughout the world. COPD and its complications also lead to a large number of deaths every year in our country. Cardiac arrhythmias and sudden cardiac death are the major complications of COPD leading to death and disability. Such cardiac complications are often a result of autonomic dysfunction. Aims and Objectives: This study aims to find out the autonomic dysfunction in moderate COPD patients by comparing their heart rate variability (HRV) parameters with age and sex matched healthy controls. Materials and Methods: After obtaining approval from the Institutional Ethics Committee, 48 patients of moderate COPD and 54 healthy subjects were assessed and compared with respect to their HRV parameters which included Mean RR, Mean HR, SDNN, NN50, pNN50, root mean square of successive differences (RMSSD), high frequency (HF), low frequency (LF), LF/HF ratio, and SD2/SD1 ratio. Results: It was found that in comparison to healthy controls, patients of moderate COPD had significant alteration in the following HRV parameters – Mean HR (P: 0.001), RMSSD (P: 0.002), SDNN (P: 0.015), NN50 (P: 0.001), pNN50 (P: 0.000), HF (NU/normalized unit) [P: 0.033], HF (%) [P: 0.002], LF (NU/normalized unit) [P: 0.033], LF (%) [P: 0.012], and LF/HF (P: 0.033). Conclusion: As there is a significant alteration of several HRV parameters in moderate COPD patients, we conclude that HRV measurement may subserve as a simple and non-invasive tool to assess autonomic dysfunction in patients of COPD at the earliest.

Efficacy of Non-contact BallistocardiographySystem to Determine Heart Rate Variability.

Background:Functions of the autonomic nervous system have cardinal importance in day-to-day life. Heart rate variability (HRV) has been shown to estimate the functioning of the autonomic nervous system. Imbalance in the functioning of the autonomic nervous system is seen to be associated with chronic conditions such as chronic kidney disease, cardiovascular diseases, diabetes mellitus, and so on.Purpose:To evaluate the efficacy of a non-contact ballistocardiography (BCG) system to calculate HRV parameters by comparing them to the parameters derived from a standard commercial software that uses an electrocardiogram (ECG).Methods:Current study captured an ECG signal using a three-channel ECG Holter machine, whereas the BCG signal was captured using a BCG sensor sheet consisting of vibroacoustic sensors placed under the mattress of the participants of the study.Results:The study was conducted on 24 subjects for a total of 54 overnight recordings. The proposed method covered 97.92% epochs of the standard deviation of NN intervals (SDNN) and 99.27% epochs of root mean square of successive differences (RMSSD) within 20 ms and 30 ms tolerance, respectively, whereas 98.84% of two-min intervals for low-frequency (LF) to high-frequency (HF) ratio was covered within a tolerance of 1. Kendall’s coefficient of concordance was also calculated, giving a P < .001 for all the three parameters and coefficients 0.66, 0.55, and 0.44 for SDNN, RMSSD, and LF/HF, respectively.Conclusion:The results show that HRV parameters captured using unobtrusive and non-invasive BCG sensors are comparable to HRV calculated using ECG.

Relationship Between Heart Rate Variability and Pulse Rate Variability Measures in Patients After Coronary Artery Bypass Graft Surgery.

Background: Heart rate variability (HRV) and pulse rate variability (PRV) measures are two kinds of physiological indices that can be used to evaluate the autonomic nervous function of healthy subjects and patients with various kinds of illness.Purpose: In this study, we compared the agreement and linear relationship between electrocardiographic signals (ECG)-derived HRV and photoplethysmographic signals (PPG)-derived right hand PRV (R-PRV) and left hand PRV (L-PRV) measures in 14 patients over 1 year after coronary artery bypass graft (CABG) surgery.Method: The ECG and PPG signals of the patient were recorded simultaneously for 10 min in a supine position. The last 512 stationary RR intervals (RRI) and peak-to peak intervals (PPI) of pulse wave were derived for data analysis. Bland-Altman plot was used to assess the agreement among HRV and both hand PRV measures, while linear regression analysis was used to examine the relationship among corresponding measures of HRV, R-PRV, and L-PRV.Result: The results revealed significant differences in total power (TP), very low-frequency power (VLF), low-frequency power (LF), high-frequency power (HF), and normalized VLF (VLFnorm) among HRV, R-PRV, and L-PRV. Bland-Altman plot analysis showed good agreements in almost all measures between R-PRV and L-PRV, except insufficient agreement was found in LF/HF. Insufficient agreements were found in root mean square successive difference (RMSSD), normalized HF (HFnorm), and LF/HF indices between HRV and L-PRV, and in VLFnorm, HFnorm, and LF/HF indices between HRV and R-PRV. Linear regression analysis showed that the HRV, R-PRV, and L-PRV measures were all highly correlated with one another (r = 0.94 ~ 1; p < 0.001).Conclusion: Though PRV measures of either hand are not surrogates of HRV measures, they might still be used to evaluate the autonomic nervous functions of CABG patients due to the moderate to good agreements in most time-domain and frequency-domain HRV measures and the strong and positive correlations among HRV and both hands PRV measures in CABG patients.

The Effect of Forest Video Using Virtual Reality on the Stress Reduction of University Students Focused on C University in Korea

The purpose of this study is to study the effect of forest videos using virtual reality (VR) on the stress of college students. The study subjects were 60 college students who watched two-dimensional (2D) and VR videos, and we compared their control heart rate variability (HRV) and electroencephalogram (EEG). As a result, it was found that the VR group had a positive effect on high frequency (HF), standard deviation of all NN intervals (SDNN), and root-mean-square of successive differences (RMSSD) compared with the control group, and the VR group had a positive effect on HF compared with the 2D group. Second, EEG, a physiological indicator, showed statistical differences in Relative Alpha Power (RA), Relative Beta Power (RB), and Ratio of SMR–Mid Beta to Theta (RSMT) in VR groups in intra-group analysis. Among them, it was investigated that watching forest videos on VR became a state of concentration and immersion due to the increase in RSMT. As a result of the above, it was investigated that forest videos using VR had a positive effect on the physiological stress on college students. Therefore, it is expected that a positive effect will occur if VR is used as an alternative to stress management for college students.

Association of lower heart rate variability with neuroimaging markers for dementia‐related pathology: The Multi‐Ethnic Study of Atherosclerosis (MESA)

AbstractBackgroundLower heart rate variability (HRV), indicating worse cardiac autonomic function, is associated with cardiovascular risk factors for dementia. We hypothesized that lower HRV would be associated with neuroimaging biomarkers for dementia‐related pathology independent of cardiovascular risk factors.MethodDuring MESA Exam 6 (2016‐19), 256 white and African‐American Wake Forest site participants completed 3T brain MRI, and 159 further completed Aβ‐PET imaging. HRV was calculated as standard deviation of normal‐to‐normal intervals (SDNN) and root mean square of successive differences (RMSSD) from 10‐second electrocardiogram at Exam 1 (2000‐02) and Exam 5 (2010‐12). We related continuous (log2‐normalized) HRV to neuroimaging parameters including mean temporal lobe cortical thickness, neurite orientation dispersion and density imaging (NODDI) free water in gray (gmFW) and white matter (wmFW), and presence of cerebral microbleeds (CMBs), lacunes, and Aβ positivity (Pittsburgh Compound B SUVR ≥1.21) using multivariable linear and logistic regression, and examined race and sex interactions. To account for potential non‐linearity, we also considered the association of lowest quartile HRV to neuroimaging markers. Regression coefficients (β [95% CI]; standard deviation units) and odds ratios (OR [95% CI]) are adjusted for age, race, sex, education, systolic blood pressure, body mass index, smoking, hypertension medication use, diabetes, and APOE genotype.ResultIn 254 participants (Exam 6 age 72.2±6.9 years; 58.7% female; 47.2% white) with HRV measurements, lower continuous Exam 1 SDNN (β = ‐0.23 [‐0.39, ‐0.07]) and RMSSD (β = ‐0.19 [‐0.33, ‐0.05]) were associated with higher wmFW. Interactions showed that CMBs were associated with lowest quartile Exam 1 SDNN (OR = 3.76 [1.15, 12.25]) and Exam 5 RMSSD (OR = 3.36 [1.07, 10.54]) in males only (sex interaction P&lt;0.001), and with Exam 1 SDNN (OR = 2.58 [1.04, 6.45]) in African‐Americans only (race interaction P = 0.039). Lower HRV was not associated with cortical thickness or presence of lacunes. In 152 participants with Aβ‐PET, no associations with Aβ deposition were found.ConclusionLower HRV from up to 16 years prior may be associated with increased neuroinflammation as measured by free water in older adults. Associations between HRV and cerebral small vessel disease markers may differ by sex or race.

Prolonged Video-EEG and Heart Rate Variability can Elucidate Autonomic Dysregulation in Infantile Apneic Seizures

BackgroundInfantile apneic seizures (IASs) are unexpected life-threatening events. We aimed to determine the utility of prolonged video-electroencephalography (vEEG) and heart rate variability (HRV) in IAS. MethodsThe study included seven infants with apneic seizures captured by vEEG, percutaneous oxygen saturation (SpO2), and electrocardiography (ECG). Interictal, preictal, and postictal HRV of patients and N2 sleep HRV of 10 age-matched controls were determined. ResultsWe analyzed seven vEEGs (duration = 17 to 87 hours) of seven patients aged three to 13 months (mean onset age of apneic event = 6.3 months). Fifteen apneic seizures (one to five per infant) were captured. The initial apneic seizure was captured at 7.5 to 76 hours (mean = 36.6 hours) after vEEG initiation. Ictal rhythmic delta/theta/fast waves were seen over temporal (five patients), central (one), and diffuse areas (one). Ictal SpO2 decreased between 1.5% and 90% (mean = 47.9%). Ictal decreased heart rate (HR) (six seizures) and ictal increased HR (14) was detected. Both decreased and increased HR was observed (five). The preictal low-frequency (LF)/high-frequency (HF) ratio was significantly higher than the interictal LF/HF ratio (P = 0.048). Preictal (P = 0.048), and postictal (P = 0.019) root mean square of successive differences (RMSSDs) of patients were lower than the sleep RMSSD of controls. These results indicated dominant sympathetic activity. RMSSD from interictal to preictal periods tended to be higher in IAS with decreased HR than in IAS with increased HR alone (P = 0.066). The postictal RMSSD showed tendency to be higher in IAS with decreased HR than in IAS with increased HR alone (P = 0.088). The decreased HR and increased RMSSD suggested not only sympathetic activity but also escalated parasympathetic activity in IAS. ConclusionsInfants with unexpected apneic events should be monitored with prolonged vEEG, SpO2, and ECG. Abnormal HRV in infants with apneic seizures might indicate additional autonomic dysregulation in IAS.

Single Slow-Paced Breathing Session at Six Cycles per Minute: Investigation of Dose-Response Relationship on Cardiac Vagal Activity.

The practice of slow-paced breathing (SPB) has been linked to a range of positive outcomes, such as decreasing symptoms of depression, anxiety, and stress, as well as increasing well-being. Among the suggested mechanisms of action, SPB has been shown to increase cardiac vagal activity (CVA). The present study aimed to investigate whether there is a dose-response relationship modulating the effects of SPB on CVA. A total of 59 participants were involved in this study. In a within-subject design, participants attended the lab five times, and realized SPB at six cycles per minute with different durations (5, 10, 15, and 20 min), as well as a control condition without SPB. CVA was indexed via the root mean square of successive differences (RMSSD). During SPB, findings showed an increase in RMSSD in all conditions compared to the control condition. However, no differences were found in RMSSD among the different session durations, during SPB or during the resting measurement completed immediately after SPB. Noteworthily, session duration showed an influence on the spontaneous respiratory frequency in the resting measurement occurring immediately after SPB. Specifically, respiratory frequency appears to decrease with session duration, thus potentially contributing to additional relaxing effects.

Cardiac and Autonomic Dysfunctions Assessed Through Recurrence Quantitative Analysis of Electrocardiogram Signals and an Application to the 6-Hydroxydopamine Parkinson's Disease Animal Model.

A classic method to evaluate autonomic dysfunction is through the evaluation of heart rate variability (HRV). HRV provides a series of coefficients, such as Standard Deviation of n-n intervals (SDNN) and Root Mean Square of Successive Differences (RMSSD), which have well-established physiological associations. However, using only electrocardiogram (ECG) signals, it is difficult to identify proper autonomic activity, and the standard techniques are not sensitive and robust enough to distinguish pure autonomic modulation in heart dynamics from cardiac dysfunctions. In this proof-of-concept study we propose the use of Poincaré mapping and Recurrence Quantification Analysis (RQA) to identify and characterize stochasticity and chaoticity dynamics in ECG recordings. By applying these non-linear techniques in the ECG signals recorded from a set of Parkinson’s disease (PD) animal model 6-hydroxydopamine (6-OHDA), we showed that they present less variability in long time epochs and more stochasticity in short-time epochs, in their autonomic dynamics, when compared with those of the sham group. These results suggest that PD animal models present more “rigid heart rate” associated with “trembling ECG” and bradycardia, which are direct expressions of Parkinsonian symptoms. We also compared the RQA factors calculated from the ECG of animal models using four computational ECG signals under different noise and autonomic modulatory conditions, emulating the main ECG features of atrial fibrillation and QT-long syndrome.

Relationship between heart rate variability and body mass index: A cross-sectional study of preschool children

Reduced heart rate variability (HRV) is associated with overweight and obesity in adults. However, little is known about this relationship in early childhood. We investigated the relationship between resting vagally-mediated HRV and body mass index (BMI) in Australian preschool children. Children were recruited from 13 non-government early learning centres located in Queensland and New South Wales, Australia. From this population-based sample, data from 146 healthy children (58 females) between 3 and 5 years of age (mean age 4.35 ± 0.44 years) were analysed. BMI was calculated from child body weight and height. Physical activity was recorded using an Actigraph wGT3x accelerometer worn at the waist of participants over 3 consecutive days. A Polar H10 chest strap measured seated, resting RR intervals for the calculation of HRV with the root mean square of successive differences (RMSSD) reflecting vagally-mediated activity. The relationship between HRV and BMI was analysed using a linear mixed model adjusted for age, sex and physical activity. Analysis revealed that RMSSD (ln) demonstrated a significant inverse relationship with BMI (β = -0.06; 95% CI = -0.12 – −0.01; p = 0.032), and the model accounted for 23% of the variance in RMSSD (ln). Notably, a one unit increase in BMI resulted in a reduction in RMSDD (ln) of 0.06. This investigation demonstrated evidence for a significant inverse linear relationship between vagally-mediated HRV and BMI in 3 – 5-year-old Australian children, similar to that of adults. Furthermore, this relationship was independent of age, sex and physical activity levels. Results may indicate that the cardiometabolic health of preschool children is, in part, influenced by the relationship between vagally-mediated HRV and weight status.

Heart rate variability and psychosocial symptoms in adolescents and young adults with cancer.

Heart Rate Variability (HRV) is a valid, scalable biomarker of stress. We aimed to examine associations between HRV and psychosocial outcomes in adolescents and young adults (AYAs) with cancer. This was a secondary analysis of baseline data from a randomized trial testing a resilience intervention in AYAs with cancer. Two widely used HRV metrics, the standard deviation of normal to normal beats (SDNN) and root mean square of successive differences (RMSSD), were derived from electrocardiograms. Patient-reported outcome (PRO) survey measures included quality of life, anxiety, depression, distress, and resilience. Linear regression models were used to test associations between HRV and PRO scores. The Wilcoxon rank sum test was used to test differences in median HRV values among participant subgroups. Among the n = 76 patients with available electrocardiograms, the mean age was 16 years (SD 3y), 63% were white, and leukemia/lymphoma was the most common diagnosis. Compared to healthy adolescents, AYAs with cancer had lower median HRV (SDNN [Females: 31.9 (12.8-50.7) vs 66.4 (46.0-86.8), p<0.01; Males: 29.9 (11.5-47.9) vs 63.2 (48.4-84.6), p<0.01]; RMSSD [Females: 28.2 (11.1-45.5) vs 69.0 (49.1-99.6), p<0.01; Males: 27.9 (8.6-48.6) vs 58.7 (44.8-88.2), p<0.01]). There was no statistically significant association between PRO measures and SDNN or RMSSD in either an unadjusted or adjusted linear regression models. In this secondary analysis, we did not find an association between HRV and psychosocial PROs among AYAs with cancer. HRV measures were lower than for healthy adolescents. Larger prospective studies in AYA biopsychosocial research are needed.

Differences in Nervous Autonomic Control in Response to a Single Session of Exercise in Bodybuilders Using Anabolic Androgenic Steroids.

Considering the role of autonomic nerve activity in blood pressure control, this study aimed to investigate the cardiac autonomic nerve responses after an aerobic exercise session in Anabolic Androgenic Steroids (AAS) users. Twenty men (AAS, n = 9; control group, n = 11) performed an aerobic exercise session (60 min, 70 to 80% of HRmax). Heart rate variability (HRV) was assessed before and during a 60-min post-exercise recovery period. RMSSD (root mean square successive difference of the RR intervals) and the LF/HF ratio (low frequency/high frequency spectra) were also evaluated. The Student's t-test for independent samples was used to compare differences between initial group characteristics. Repeated measures ANOVA was used to compare pre- and post-exercise HRV recovery (p < 0.05). AAS had a lower SDNN (standard deviation of the intervals) (40.8 ± 16.8 vs. 71.6 ± 24.7 ms; p = 0.04, d = 1.4) and a higher LF/HF (3.4 ± 2.1 vs. 1.8 ± 0.9%; p = 0.03, d = 0.9) before exercise. AAS and controls had similar RMSSD (14.0 ± 15.8 vs. 18.9 ± 12.1 ms; p = 0.20) and a LF/HF (2.8 ± 1.6 vs. 2.4 ± 1.2 ms; p = 0.41) immediately post-exercise. The between-groups comparison revealed a higher HF/LF at 30 min (4.3 ± 1.4 vs. 2.5 ± 1.3%; p = 0.008, d = 1.3) and 60 min (5.0 ± 2.2 vs. 2.3 ± 0.8%; p = 0.001, d = 1.6) for the AAS group in the recovery time. This study demonstrated impaired parasympathetic activity at rest and immediately after the exercise session as an adverse effect of AAS usage, but similar behavior regarding the restoration of sympathetic activity.

Acute effects of exercise on cardiac autonomic function and arterial stiffness in patients with stable coronary artery disease

Objectives. To examine the acute effect of a maximal aerobic exercise effort on aortic, peripheral arterial stiffness and cardiovagal modulation of trained and untrained patients with coronary artery disease (CAD). Design. Cross-sectional study. Methods. Eighteen untrained patients with CAD, 18 trained patients with CAD, and 18 apparently healthy trained subjects were sampled and matched for age and body mass index. Aortic and peripheral stiffness were measured by applanation tonometry estimates of carotid-femoral (cfPWV), carotid-radial (crPWV), and carotid-dorsalis pedis pulse wave velocity (cdPWV), respectively. Cardiovagal modulation was assessed by heart-rate variability (HRV) indices including the standard deviation of normal-to-normal RR intervals (SDNN), root-mean-square of successive differences (RMSSD), and the high-frequency power band (HF). cfPWV, crPWV, cdPWV, and HRV indices were measured at rest, 10 and 30 min following a maximal cardiopulmonary exercise test on a cycle ergometer. Results. No differences were observed between groups at rest nor over time in indices of HRV, cfPWV and cdPWV. Still, main effects of time were observed in cfPWV (p < .001; ɳ 2 = 0.313) and cdPWV (p = .003, ɳ 2 = 0.111), RMSSD (p < .001, ɳ 2 = 0.352), HF (p < .001, ɳ 2 = 0.265) and LF/HF (p = .001, ɳ 2 = 0.239), as cdPWV, RMSSD, and HF were reduced 10 min following exercise, whereas cfPWV and LF/HF were increased. Changes in cPP were associated with changes in HRV from rest to min 10 (HF, r = 0.302), and to min 30 (HF, r = 0.377; SDNN, r = 0.357; RMSSD, r = 0.429). Conclusion. Training level and CAD do not seem to influence arterial stiffness and cardiac autonomic responses to maximal exercise.

Single Vibroacoustic Impact Effect of Singing Bowls over the Psycho-Emotional State and Cardiovascular System Work

This article presents a two-stage study result of the author's method of vibroacoustic massage using singing bowls application. At the first stage, the effect of vibroacoustic massage single application over psycho-emotional characteristics was studied. 19 studied volunteers took part in our study. The testing results before and after exposures were compared according to the WAM (Weighted average mark), Zung, and Spielberg-Khanin tests. The study of the psycho-emotional sphere showed that after the vibroacoustic massage procedure, the indicators of "well-being" and "activity" of the WAM test significantly improved (p = 0.002). In addition, the depression level determined by the Zung test, personal anxiety indicators (p = 0.004), and situational anxiety ones (p = 0.028) decreased. At the second stage, 62 volunteers were divided into two groups. The first group underwent a vibroacoustic massage session according to the patented author's method. The second group received only acoustic exposure using only singing bowls. Differences in the Kerdo index were revealed in the dynamics, and in the first group, the changes were less significant than in the second one. Changes in heart rate variability characteristics for both groups were similar: there was an increase in parasympathetic influences at rest and during the orthostatic test (increased levels of RMSSD (Root Mean Square of Successive Differences), NN50, pNN50) and a decrease in sympathetic effects at rest and their slight increase with orthostatic loading (TINN, RR triangular index). The dynamics were more significant in the first group that received a vibroacoustic massage session. When assessing changes in the neurovegetative regulation levels activity of the heart rhythm, the main difference was associated with very low-frequency waves power dynamics during the orthostatic test. Thus, vibroacoustic massage using singing bowls improves the psycho-emotional state, reduces depression and anxiety, and increases Parasympaticus (autonomic nervous system) activity.

Slow deep breathing modulates cardiac vagal activity but does not affect peripheral glucose metabolism in healthy men

Parasympathetic nervous system innervates peripheral organs including pancreas, hepatic portal system, and gastrointestinal tract. It thereby contributes to the regulation of whole-body glucose metabolism especially in the postprandial state when it promotes secretion of insulin and enhances its action in major target organs. We now aimed to evaluate the effect of parasympathetic modulation on human glucose metabolism. We used slow deep breathing maneuvers to activate the parasympathetic nervous system and tested for effects on metabolism during an oral glucose tolerance test in a randomized, controlled, cross-over trial in 15 healthy young men. We used projections towards the heart as a readout for parasympathetic activity. When analyzing heart rate variability, there was a significant increase of RMSSD (root mean square of successive differences) when participants performed slow deep breathing compared to the control condition, indicating a modulation of parasympathetic activity. However, no statistically significant effects on peripheral glucose metabolism or energy expenditure after the glucose tolerance test were detected. Of note, we detected a significant association between mean heart rate and serum insulin and C-peptide concentrations. While we did not find major effects of slow deep breathing on glucose metabolism, our correlational results suggest a link between the autonomic nervous system and insulin secretion after oral glucose intake. Future studies need to unravel involved mechanisms and develop potential novel treatment approaches for impaired insulin secretion in diabetes.

Insomnia in Emotional Labor: Its Role in Autonomic Nervous System Regulation.

ObjectiveThe relation between female emotional laborers’ sleep quality and autonomic nervous system activity was investigated. MethodsThirty-three subjects’ heart rate variability (HRV) data and results of self-reported scale on sleep, depression, anxiety and suicidality, were collected. Subjects were classified into good sleeper (GS) and poor sleeper (PS) groups relying on sleep quality. Changes of HRV between working time and resting time in each group were compared. ResultsThe PS group showed significantly lower difference in root mean square of successive differences (RMSSD), percentage of successive normal-to-normal intervals that differ by more than 50 ms (pNN50), and natural logarithm high-frequency (LnHF) when they were working as compared to when they were resting, which means decreased function of the parasympathetic nervous system (PNS). Repeated measures analysis of covariance showed that the group effect was significant only for LnHF, with score of depression scale as a covariate. ConclusionFemale emotional laborers who complain of sleep difficulty may have decreased function of the PNS. Therefore, good sleep quality is essential for maintaining and promoting mental and physical health of women engage in emotional labor.

Heightened Stress Reactivity in Response to an Attachment Related Stressor in Patients With Medically Treated Primary Hypertension.

Background: A heightened stress reactivity to mental stress tasks has been shown in hypertensive patients and might contribute to a higher disease risk. We investigated this hyperreactivity with regard to an attachment related stressor that focuses on emotions instead of performance and we examined whether this effect can also be found in patients on antihypertensive drugs.Materials and Methods: Fifty patients with primary hypertension, treated with at least one antihypertensive drug, were compared with 25 healthy individuals. After 10 min of rest, they participated in an attachment-related interview (Adult Attachment Projective picture system, AAP) and were exposed to an attachment-related stressor (Separation Recall, SR), a short-time stressor which activates attachment-related emotions and thoughts by talking 5 min about a personal experience of loneliness. Blood samples to measure adrenocorticotrope hormone (ACTH), cortisol, norepinephrine, epinephrine, and dopamine were taken. Blood pressure, heart rate and arterial stiffness were measured at rest, after AAP, after SR and 10 min after recovery. Standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive differences (RMSSD) were calculated. Parameters were compared using Mann Whitney U-test and linear mixed-effects regression models controlling for age and body mass index (BMI) after logarithmic transformation if appropriate.Results: Healthy test persons were younger and had lower BMI than patients. Comparing the two groups there were no significant differences in blood pressure and heart rate at rest. Both stressors provoked a significant response in almost all parameters. Results of the post-estimation of contrasts from linear mixed-effects regression models showed a steeper rise in systolic BP and arterial stiffness as well as a more pronounced decline in SDNN in hypertensive patients than in healthy controls. Levels of cortisol rose earlier and higher in hypertensive patients than in healthy controls.Conclusion: Vascular, autonomic, and hypothalamic pituitary adrenal axis response is heightened in medicated subjects with hypertension in response to attachment-focused stressors compared to healthy subjects. We conclude that the remaining hyper-reactivity even with sufficient antihypertensive medication still poses a substantial risk for affected patients. New ways to diminish this risk should be developed.

Classification of heart sounds based on quality assessment and wavelet scattering transform

Automatic classification of heart sound plays an important role in the diagnosis of cardiovascular diseases. In this study, a heart sound sample classification method based on quality assessment and wavelet scattering transform was proposed. First, the ratio of zero crossings (RZC) and the root mean square of successive differences (RMSSD) were used for assessing the quality of heart sound signal. The first signal segment conforming to the threshold standard was selected as the current sample for the continuous heart sound signal. Using the wavelet scattering transform, the wavelet scattering coefficients were expanded according to the wavelet scale dimension, to obtain the features. Support vector machine (SVM) was used for classification, and the classification results for the samples were obtained using the wavelet scale dimension voting approach. The effects of RZC and RMSSD on the results are discussed in detail. On the database of PhysioNet Computing in Cardiology Challenge 2016 (CinC 2016), the proposed method yields 92.23% accuracy (Acc), 96.62% sensitivity (Se), 90.65% specificity (Sp), and 93.64% measure of accuracy (Macc). The results show that the proposed method can effectively classify normal and abnormal heart sound samples with high accuracy.

The Association Between Biomarkers Of Resilience And Readiness With Fitness Changes In College Soccer Players

The free testosterone to cortisol ratio (fTC) and heart rate variability (HRV) indices have been independently proposed as objective biomarkers of physiological resilience and readiness, respectively. It is hypothesized that individuals that enter a training period with high resilience and readiness would have a greater positive response to the training. PURPOSE: Therefore, the purpose of this study was to investigate the association between fTC and HRV with fitness changes in division I male college soccer players. METHODS: Two division I teams were recruited to participate in this study. Participants completed an orthostatic HRV challenge (supine, sitting, standing) and provided blood samples prior to the 6-week Spring training period. The HRV indices of root mean square of successive differences (RMSSD) and high frequency power (autoregressive, normalized; HF) were calculated in all postural conditions. Blood samples were assayed for free testosterone and cortisol using competitive binding ELISAs. Participants completed the yo-yo intermittent recovery test (YYIR) before and after the 6-week training period and the absolute increase in distance (m) achieved during the YYIR represented the change in fitness (YYIRΔ). Separate linear regression models tested the association of fTC and all HRV indices and their interactions with YYIRΔ. All predictors were first centered and scaled and alpha level was set at p < 0.05 for all models. RESULTS: Participants (n = 21, age = 19.5 ± 1.0 years, height = 179.0 ± 6.4 cm, weight = 76.9 ± 9.4 kg, body fat = 12.6 ± 4.3 %) from the two teams did not differ in YYIRΔ (mean ± SD = 438 ± 212, p = 0.64). A significant association with YYIRΔ was observed for the interaction between fTC and HFsitting (F(3,17) = 4.31, β = 4.92,p = 0.02, R2 = 0.33). No other indices or interactions were significantly associated with YYIRΔ. CONCLUSIONS: These results suggest that HRV and fTC represent potential objective pre-training biomarkers capable of identifying athletes that will be most responsive to individualized fitness and conditioning programs. Further research is necessary to confirm the utility of these specific objective biomarkers in larger cohorts and across multiple training situations.

Ultra-short Heart Rate Variability Is Associated With Arterial Stiffness In Young Healthy Individuals

Heart rate variability (HRV), the time-difference between heartbeats, is a convenient marker of autonomic function. Single-day laboratory studies examining associations between HRV and arterial stiffness, a strong predictor of future cardiovascular events and all-cause mortality, have produced mixed results. This may be due to a failure to account for body position or lability in day-to-day HRV. PURPOSE: To assess relationships between self-recorded, multi-day, supine and standing HRV measures with arterial stiffness in young healthy adults. METHODS: Twenty-one males (24 ± 5 yrs; 24 ± 17% body fat) and 20 females (21 ± 3 years; 34 ± 7% body fat) recorded ultra-short (i.e., 60-s), post-waking HRV measures in supine and standing positions for 7 days via a Bluetooth heart rate monitor and smartphone application. Following the HRV measurement period, participants reported to the laboratory in a fasted state during morning hours. Augmentation index for a heart rate of 75 beats per minute (AIx75) via pulse wave analysis, and carotid-femoral pulse wave velocity (cf-PWV) via applanation tonometry were acquired as non-invasive indices of arterial stiffness. Associations between average supine and standing 7-day natural logarithm of the root-mean square of successive differences (lnRMSSDavg), and their coefficients of variation (lnRMSSDcv), with AIx75 and cf-PWV were assessed. RESULTS: Supine and standing lnRMSSDavg were 4.4 ± 0.4 and 3.5 ± 0.5 ms in men, and 4.1 ± 0.6 and 3.1 ± 0.5 ms in women, respectively. Supine and standing lnRMSSDcv were 8.1 ± 3.4 and 10.6 ± 5.4% in men, and 9.8 ± 5.2 and 13.0 ± 4.4% in women, respectively. In men, supine lnRMSSDavg (r = -.62) and standing lnRMSSDcv (r = .55) were associated with cf-PWV (6.2 ± 0.84 m/s; P < 0.05), but no associations were observed between HRV indices and AIx75 (2.2 ± 12.3%; P > 0.05). In women, supine lnRMSSDavg (r = -.52) and lnRMSSDcv (r = .52), and standing lnRMSSDmean (r = -.51) were associated with cf-PWV (5.8 ± 0.5 m/s; P < 0.05), and supine lnRMSSDcv was associated with AIx75 (5.7 ± 9.8%; P < 0.05). CONCLUSIONS: Multi-day, self-recorded, HRV measures were related to cf-PWV in young healthy men and women, and AIx75 in women. More numerous and stronger associations between HRV and cf-PWV vs. AIx75 portend a greater autonomic influence on proximal aortic vs. systemic arterial stiffness.