Fluctuations In Heart Rate Variability Research Articles

Robust and time-resolved estimation of cardiac sympathetic and parasympathetic indices.

The time-resolved analysis of heart rate (HR) and heart rate variability (HRV) is crucial for the evaluation of the dynamic changes of autonomic activity under different clinical and behavioral conditions. Standard HRV analysis is performed in the frequency domain because the sympathetic activations tend to increase low-frequency HRV oscillations, while the parasympathetic ones increase high-frequency HRV oscillations. However, a strict separation of HRV in frequency bands may cause biased estimations, especially in the low frequency range. To overcome this limitation, we propose a robust estimator that combines HR and HRV dynamics, based on the correlation of the Poincaré plot descriptors of interbeat intervals from the electrocardiogram. To validate our method, we used electrocardiograms gathered from open databases where standardized paradigms were applied to elicit changes in autonomic activity. Our proposal outperforms the standard spectral approach for the estimation of low- and high-frequency fluctuations in HRV, and its performance is comparable to newer methods. Our method constitutes a valuable, robust, time-resolved, and cost-effective tool for a better understanding of autonomic activity through HR and HRV in healthy state and potentially for pathological conditions.

Enhancing Vagal Tone, Modulating Heart Rate Variability with Auricular Acupressure at Point Zero: A Randomized Controlled Trial.

Point Zero located within the vagus nerve's auricular branch shows promise in addressing imbalances. This study aims to explore its effects on vagal activity using auricular acupressure (AA), measured through heart rate variability (HRV). This single-blinded randomized controlled trial involved 114 healthy volunteers randomly assigned to receive AA (AA group, n = 57) or sham-AA (SA group, n = 57) at Point Zero. The 30-minute procedure comprised six stages: T1 and T2 (pre-intervention), T3 to T5 (intervention), and T6 (post-intervention). Interventions involving 30-s acupoint pressure stimulations at T3 and T5. The HRV-measured outcomes included heart rate (HR), standard deviation of R-R intervals (SDNN), root mean square of successive RR interval differences (RMSSD), natural logarithm of low-frequency power (LnLF), and natural logarithm of high-frequency power (LnHF). In addition, respiratory rate (RR) was monitored for its stability. The AA group demonstrated a significant decrease in HR and increases in SDNN, RMSSD, and LnHF from stages T3 to T6 compared with T1 (baseline), notably prominent at T3 (median changes [25th; 75th percentiles]: -2 [-5; -1], 17.85 [9.65; 31.72], 4.9 [1.08; 10.65], 0.26 [0.00; 0.62], respectively) and T5 (-3 [-6; -1], 19.45 [10.6; 32.89], 6.17 [-0.17; 16.34], 0.40 [-0.14; 0.83], respectively), while the SA group did not. LnLF showed nonsignificant alterations, and RR remained stable in both groups. Despite minor HRV fluctuations, the AA group consistently displayed significantly higher changes in SDNN and RMSSD compared with the SA group from T3 onwards. HR remained unchanged at T6, and LnHF significantly differed only at T5. AA at Point Zero may promptly enhance vagal activity, evident in the modulation of HRV, notably pronounced with pressure stimulation, and can be sustained for at least 5 min. Further studies are needed to assess its long-term effectiveness and efficacy in preventing or treating patients.(Clinical Trial Registration: NCT05586698).

Practice effects of a breathing technique on pilots’ cognitive and stress associated heart rate variability during flight operations

Commercial pilots endure multiple stressors in their daily and occupational lives which are detrimental to psychological well-being and cognitive functioning. The Quick coherence technique (QCT) is an effective intervention tool to improve stress resilience and psychophysiological balance based on a five-minute paced breathing exercise with heart rate variability (HRV) biofeedback. The current research reports on the application of QCT training within an international airline to improve commercial pilots’ psychological health and support cognitive functions. Forty-four commercial pilots volunteered in a one-month training programme to practise self-regulated QCT in day-to-day life and flight operations. Pilots’ stress index, HRV time-domain and frequency-domain parameters were collected to examine the influence of QCT practice on the stress resilience process. The results demonstrated that the QCT improved psychophysiological indicators associated with stress resilience and cognitive functions, in both day-to-day life and flight operation settings. HRV fluctuations, as measured through changes in RMSSD and LF/HF, revealed that the resilience processes were primarily controlled by the sympathetic nervous system activities that are important in promoting pilots’ energy mobilization and cognitive functions, thus QCT has huge potential in facilitating flight performance and aviation safety. These findings provide scientific evidence for implementing QCT as an effective mental support programme and controlled rest strategy to improve pilots’ psychological health, stress management, and operational performance.

Fascia iliaca compartment block mitigates the fluctuations in heart rate variability and reduces pain with opioid consumption in elderly individuals with hip fractures: A randomized controlled trial

BackgroundHip fractures, commonly known as the “terminal fracture of life,” frequently necessitate prompt surgical intervention and are accompanied by significant perioperative pain. ObjectiveThis investigation was performed to assess the impact of fascia iliaca compartment block (FICB) on heart rate variability during the perioperative period in elderly individuals with hip fractures. DesignSingle-center, randomized, controlled clinical trial. SettingThe study was conducted from September 2021 to February 2023 at one tertiary care hospital in China. ParticipantsPatients aged ≥60 years who underwent general anesthesia for hip fracture surgery were screened for enrollment. Eighty patients were initially assessed for eligibility, 70 underwent randomization, and 62 were included in the final analysis. MethodsPreoperatively, the patients were randomly allocated to either receive (Group F) or not receive (Group C) ultrasound-guided suprainguinal FICB. The primary endpoint was heart rate variability indicators at the corresponding time points. The secondary endpoints included the mean arterial pressure and heart rate measured at different time points [upon admission to the operating room (T1), during positioning (T2), at the time of skin incision (T3), 30 min after the start of surgery (T4), and 6 h postoperatively (T5)] and visual analogue scale (VAS) score, dose of oral pain medication over 24 h, and satisfaction scores were valued. ResultsCompared with Group C, Group F had a significantly reduced low-frequency band, high-frequency band, and low-/high-frequency band ratio at T3, T4, and T5 (P < 0.05). Group F also had a lower heart rate at T2, T3, T4, and T5 (P < 0.05). Moreover, Group F had lower flurbiprofen dosages at 24 h postoperatively (P < 0.05) and lower resting VAS scores at 6 and 24 h postoperatively (P < 0.05). ConclusionUtilization of ultrasound-guided FICB has the potential to yield efficacious analgesic effects, mitigate the pronounced fluctuations in heart rate induced by surgical stimulation, and maintain autonomic function stability to a certain degree.

Visually assessing work performance using a smartwatch via day-to-day fluctuations in heart rate variability.

To optimize workplace health promotion, a simple method for quantifying allostatic load response is needed. This study examines the feasibility of optimizing objective anxiety and presenteeism monitoring using daily smartwatch-measured ultra-short heart rate variability (HRV). Office workers without diagnosed disease prospectively performed 30 s HRV self-measurement each morning for two months and responded to the State-Trait Anxiety Inventory (STAI) and Work Limitation Questionnaire (WLQ). Logistic regression analysis examined daily HRV parameters in the high-trait anxiety group (HTA, STAI ≥ 40) using mean and variance HRV, age, self-reported gender, and body mass index (BMI). The ideal cutoff value enabled comparison of WLQ using the Mann-Whitney U test. Heart rate variability data were collected for 279 participants (male ratio, 83.9%; age, 42 ± 10 years) who completed questionnaires and monitored HRV for 30+ days. Compared to the low-trait anxiety group, HTA exhibited higher variance of the log-transformed coefficient of component variance of high-frequency component (LnccvHF) and low-frequency per HF (Lnccv L/H), in addition to differences in the means of these HRV parameters. In addition to BMI (odds ratio [OR] = 0.92, p = 0.02) and mean LnccvL/H (OR = 10.75, p < 0.01), the variance of Lnccv L/H was an independent predictor of HTA (OR = 2.39E + 8, p = 0.011). The daily Lnccv L/H dispersion group had a lower WLQ productivity loss score (p = 0.02, r = 0.17). By focusing on HRV dispersion status, this simple and instantly applicable daily HRV monitoring system enables optimized quantitative monitoring of anxiety and productivity.

The influence of insulin resistance variables on heart rate variability indices in mature men under Russia’s North conditions

BACKGROUND: Heart rate autonomic regulation can go out of balance which is normally assessed by the heart rate variability (HRV) indices. Similarly, it is relevant to research if and how HRV fluctuations can be influenced by varying signs of insulin resistance since they are quite common in Northern men. At present, there is no evidence of this influence in the North residents of older ages.AIM: This study aimed to comparatively assess heart rate variability in mature men who do or do not feature metabolic signs of insulin resistance.MATERIALS AND METHODS: Seventy-three mature aged male residents of Magadan Region, Caucasian by origin, were examined. All the subjects were divided into two groups: Group without insulin resistance signs (HOMA-IR index &lt; 2.5 units) and Group with insulin resistance signs (HOMA-IR index &gt; 2.5 units). We used immunochemiluminescent and enzymatic methods, and heart rate variability was assessed using the Varikard (Russia).RESULTS: Our research showed that 48% of all the examinees exhibited signs of insulin resistance along with an increase in the sympathetic activity in heart rate regulation. We also identified the heart rate indicators that had proved to undergo the most significant changes depending on the HOMA-IR index and the presence or absence of signs of insulin resistance: MxDMn, pNN50, SDNN, AMo50, SI, TP, HF, LF, and Body Mass.CONCLUSION: In general, the results obtained allow for ascertaining the high proportion of male Northerners of mature age with signs of insulin resistance. We also claim that those examinees demonstrate an autonomic imbalance and a moderate dominance of the sympathetic activity with a simultaneous decrease in activation of the parasympathetic link of autonomic nervous system and high body mass variables. At the same time, the correlations and causal associations among signs of insulin resistance, activation of the sympathetic link of autonomic nervous system, and overweight remain unclear. Apparently, all the analyzed features are likely to complement each other rather than completely exclude each other. The triad of obesity, signs of insulin resistance, and activation of the sympathetic link of autonomic nervous system is a driving factor for significant health risks. This study is expected to spread the use of the method of assessing heart rate variability based on insulin resistance signs as well as in reliance on metabolic disorders in general in a sample of mature men.

Changes in Heart Rate Variability with Induction of Gastric Ulcers in Adult Horses.

Gastric ulceration can be induced by athletic training and is a significant welfare concern. The objective of this study was to evaluate the effect of gastric ulcer induction on heart rate variability (HRV) in the horse. We hypothesized that induction of gastric ulcers would decrease HRV and increase low frequency fluctuations, consistent with increased sympathetic tone. A convenience sample of 8 horses in a larger study were enrolled. Horses were randomly assigned to receive water or 2 mg/kg omeprazole orally once daily for 28 days. Gastric ulcers were induced through intermittent feed withholding on days 21 to 28. Gastroscopy was performed and gastric ulcers were graded (0-IV) by three blinded reviewers on days 21 and 28. Continuous electrocardiograms were obtained for one hour at the start and end of ulcer induction. HRV was assessed in 1-hour recordings for time domain variables and 5 minute sections for frequency domain analysis. HRV and ulcer grade across treatments were compared by a mixed effect model, with treatment and time as fixed effects and horse as a random effect. Gastric ulcer grade increased with induction protocol (P < .0001) and decreased with omeprazole treatment (P=.0007). Omeprazole treatment increased R-R intervals (P=.01) and decreased ratio of low frequency/high frequency signal (P=.008) as compared to horses receiving water. This was attributable to decreasing low frequency fluctuations (P=.05). While limited by the small sample size (four horses/treatment), this study suggests that omeprazole treatment decreases heart rate, and LF/HF ratio during ulcer induction, consistent with a decrease in sympathetic tone.

Effects of training on the heart rate variability of competitive soccer players: A systematic review with meta-analysis

Heart rate variability (HRV) has become a popular method for monitoring readiness, recovery, and other training-derived parameters to optimize physical performance. This systematic review aimed to examine the impact of training interventions on HRV fluctuations in competitive soccer players. The EBSCO, Web of Sciences (WOS), and Cochrane databases were used for the search. After identifying 293 studies, 13 were included in a qualitative analysis and 6 in a quantitative analysis. Training had a small and nonsignificant effect on HRV in competitive soccer players (Effect Size (ES) = 0.143, Standard Error (SE) = .108, p = .186, 95% confidence interval (CI) [−0.69, 0.355]). Soccer-focused training resulted in higher HRV scores than combined training (Q(2) = 38.13, p = .05). Higher ES were found for frequency domain parameters ( p = .047; d = 0.059), night assessment ( p = .016; d = 0.453), and soccer-focused training ( p = .006; d = 0.366). HRV was also found to have a greater impact on females ( p = .027; d = 0.275) and/or professional soccer players ( p = .007; d = 0.302). Soccer training had a minimal and nonsignificant effect on HRV.

HEART RATE VARIABILITY AND BASIC HEMODYNAMIC PARAMETERS IN MEDICAL STUDENTS IN SEASONS WITH DIFFERENT PHOTOPERIOD

One of the main external factors that contributes to the seasonal functional reorganization of the organism in the process of adaptation is seasonal photoperiodic variability. Day length is affecting not only visual function, but also all physiological and behavioural processes controlled by the circadian rhythm system. The person's ability to adapt to changes in external factors is especially important for medical students who experience significant mental overload in the process of studying at a university. The study goal was to investigate the features of the main hemodynamic parameters and heart rate variability in medical students in the spring and autumn periods, with taking into account gender differences. Materials and methods: A cross-sectional study of 304 students of the North-Ossetian State Medical Academy (Russia) comprising 233 female and 71 male subjects was performed during periods of elongation (spring) and shortening (autumn) of the photoperiod. Blood pressure (BP), pulse rate (HR), parameters of heart rate variability (HRV) were measured. Results: The students showed an increase in DBP and MBP rates within the normal range in autumn. Hemodynamic parameters of SBP, DBP, PBP, MBP in males were significantly higher than in females group, regardless of the season. Interseasonal differences in HRV parameters (LF, THF, PHF, PLF, LF/HF, IC) were revealed. From spring to autumn period, LF decreases from 980.22 (590.30; 1445.83) to 690.68 (438.81; 1170.15) ms2 against the background of a decrease in the dominant period of the high-frequency component of the spectrum (THF) from 5.40 (3 .77; 6.10) to 3.71 (3.08; 5.54) s. The contribution of the high-frequency component (PHF) to the total power of HRV fluctuations increases by 10.4%, and the low-frequency component (PLF) decreases by 6.45% as the photoperiod shortens. The centralization index (IC) also declines from 2.58 (1.42; 3.90) to 1.61 (0.97; 2.98); p=0.0076. Parameters of Mean, Mo, RMSSD, pNN50, SDNN, TP, HF, PHF in spring are lower in males in comparison with females, while parameters of HR, SI, PLF, LF/HF, VLF/HF, IC, PARS are higher in males. Conclusions: It was indicated that the change in the photoperiod trend is an important mediator of heart rate variability in the annual cycle. The lengthening of the photoperiod in the spring season is accompanied by a shift in the vegetative balance of students towards an increase in the tonus of the sympathetic division of the autonomic nervous system (ANS) together with the involvement of the central circuit of the heart rhythm regulation. In autumn, on the background of shorter daylight duration hours, parasympathetic influences are intensified and autonomic regulation circuit is most active. In the common trend of increased sympathetic activity of the ANS and activation of the central regulatory circuit in the spring, in young males these changes are indicated at greater extent.

Osteopathic Manipulative Treatment Regulates Autonomic Markers in Preterm Infants: A Randomized Clinical Trial.

Osteopathic manipulative treatment (OMT) has been found to be effective in the context of premature infants. Nonetheless, no studies have investigated the immediate effects of OMT on heart rate variability (HRV). As altered HRV reflects poor or worsening newborn’s clinical conditions and neurodevelopment, should OMT improve HRV fluctuations, it could become a relevant intervention for improving the care of preterm newborns. Therefore, this study aimed to evaluate whether OMT could affect HRV. The study was carried out at the Buzzi Hospital in Milan. From the neonatal intensive care unit, ninety-six preterm infants (41 males) were enrolled and were randomly assigned to one of two treatment groups: OMT or Static Touch. The infants were born at 33.5 weeks (±4.3) and had a mean birth weight of 2067 g (±929). The study had as primary outcome the change in the beat-to-beat variance in heart rate measured through root mean square of consecutive RR interval differences (RMSSD); other metrics were used as secondary and exploratory analyses. Despite the lack of statistically significant results regarding the primary outcomeand some study limitations, compared to static touch, OMT seemed to favor a parasympathetic modulation and improved HRV, which could reflect improvement in newborn’s clinical conditions and development.

Trends in Daily Heart Rate Variability Fluctuations Are Associated with Longitudinal Changes in Stress and Somatisation in Police Officers

The emergence of wearable sensors that allow for unobtrusive monitoring of physiological and behavioural patterns introduces new opportunities to study the impact of stress in a real-world context. This study explores to what extent within-subject trends in daily Heart Rate Variability (HRV) and daily HRV fluctuations are associated with longitudinal changes in stress, depression, anxiety, and somatisation. Nine Dutch police officers collected daily nocturnal HRV data using an Oura ring during 15–55 weeks. Participants filled in the Four-Dimensional Symptoms Questionnaire every 5 weeks. A sample of 47 five-week observations was collected and analysed using multiple regression. After controlling for trends in total sleep time, moderate-to-vigorous physical activity and alcohol use, an increasing trend in the seven-day rolling standard deviation of the HRV (HRVsd) was associated with increases in stress and somatisation over 5 weeks. Furthermore, an increasing HRV trend buffered against the association between HRVsd trend and somatisation change, undoing this association when it was combined with increasing HRV. Depression and anxiety could not be related to trends in HRV or HRVsd, which was related to observed floor effects. These results show that monitoring trends in daily HRV via wearables holds promise for automated stress monitoring and providing personalised feedback.

Analysis of frequency ranges of heart rate variability and estimation errors of respiratory sinus arrhythmia in aging

The clinical significance of heart rate variability (HRV) was assessed at the end of the last century, despite the fact that HRV studies have been conducted since the mid-19th century. In recent years, HRV has been increasingly used for non-invasive monitoring of the autonomic nervous system. However, the interpretation of HRV features is still not fully understood and widely discussed. It is known that HRV fluctuations are created by various regulatory systems of the body, which have different natural frequencies. The estimated HRV parameters are SDNN and RMSSD indicators – standard deviations of a number of RR-intervals and a number of first differences of RR-intervals, respectively. The purpose of the article was to calculate the power decrease with aging in different frequency ranges, analyze the errors of spectral estimates, and compare the spectral estimates of RSA with the values of RMSSD indicators. Simultaneous ECG and respiration records from the Fantasia Physio Bank database were used as initial data. For reference estimates, the powers in the range of respiration rate found from the records of respiration measurements are taken. It is shown that with age the power of the HF range decreases most rapidly, and the VLF range decreases most slowly. HF oscillation amplitudes are compared with RMSSD values. It is proposed to consider the RMSSD indicator as an assessment of the speed parameter of the regulatory system. Spectral methods are used to estimate the power of individual frequency ranges. For non-invasive monitoring of the autonomic nervous system, spectral estimates of the power of the LF and HF ranges are used. With aging, stress, and various diseases, the activity of regulatory systems decreases, but it remains unclear in which regulatory systems and to what extent violations occur.

Correlation of obesity indices with heart rate variability in young male adults

Background: Due to its well-known risk for hypertension, diabetes mellitus, and cardiovascular diseases, obesity has become a major public health issue. The sympathetic nervous system can be triggered by body fat resulting in an autonomic impairment. The aim of the present study was to analyse the relationship between indicators of obesity and heart rate variability (HRV) in young adult males. Aims and Objectives: The aims of the study were to compare obesity indicators with HRV in young adult males and to examine whether there is any link between obesity and HR variability. Materials and Methods: This research was directed on 110 healthy college MBBS male students between 18 and 22 years of age. The study population (n = 110) was classified using the body mass index into a control group (BMI = 18.5–22.9 kg/m²) and a study group (BMI = 23.0–29.9 kg/m²). Approval from the Institutional Ethical Committee was obtained before beginning the study. The central obesity assessment was performed using waist circumference and waist to hip ratio. All HRV fluctuations were determined by a 5-min time domain and frequency domain power spectral density analysis using the ML4818 Power Lab 15T software. Results: Unpaired t-test was used to analyse all parameters of the study (control and study group). The results implied a lower level of parasympathetic and a higher sympathetic activity in the study group when matched against the control group. Conclusion: Due to an imbalance of the sympathovagal action of the autonomic nervous system, overweight or pre-obese individuals are more likely to suffer from cardiometabolic disorders in the future.

Analysis of Dynamic Changes in Cognitive Workload During Cardiac Surgery Perfusionists' Interactions With the Cardiopulmonary Bypass Pump.

This novel preliminary study sought to capture dynamic changes in heart rate variability (HRV) as a proxy for cognitive workload among perfusionists while operating the cardiopulmonary bypass (CPB) pump during real-life cardiac surgery. Estimations of operators' cognitive workload states in naturalistic settings have been derived using noninvasive psychophysiological measures. Effective CPB pump operation by perfusionists is critical in maintaining the patient's homeostasis during open-heart surgery. Investigation into dynamic cognitive workload fluctuations, and their relationship with performance, is lacking in the literature. HRV and self-reported cognitive workload were collected from three Board-certified cardiac perfusionists (N = 23 cases). Five HRV components were analyzed in consecutive nonoverlapping 1-min windows from skin incision through sternal closure. Cases were annotated according to predetermined phases: prebypass, three phases during bypass, and postbypass. Values from all 1min time windows within each phase were averaged. Cognitive workload was at its highest during the time between initiating bypass and clamping the aorta (preclamp phase during bypass), and decreased over the course of the bypass period. We identified dynamic, temporal fluctuations in HRV among perfusionists during cardiac surgery corresponding to subjective reports of cognitive workload. Not only does cognitive workload differ for perfusionists during bypass compared with pre- and postbypass phases, but differences in HRV were also detected within the three bypass phases. These preliminary findings suggest the preclamp phase of CPB pump interaction corresponds to higher cognitive workload, which may point to an area warranting further exploration using passive measurement.

Utilizing heart rate variability to predict ICU patient outcome in traumatic brain injury

BackgroundPrediction of patient outcome in medical intensive care units (ICU) may help for development and investigation of early interventional strategies. Several ICU scoring systems have been developed and are used to predict clinical outcome of ICU patients. These scores are calculated from clinical physiological and biochemical characteristics of patients. Heart rate variability (HRV) is a correlate of cardiac autonomic regulation and has been evident as a marker of poor clinical prognosis. HRV can be measured from the electrocardiogram non-invasively and monitored in real time. HRV has been identified as a promising ‘electronic biomarker’ of disease severity. Traumatic brain injury (TBI) is a subset of critically ill patients admitted to ICU, with significant morbidity and mortality, and often difficult to predict outcomes. Changes of HRV for brain injured patients have been reported in several studies. This study aimed to utilize the continuous HRV collection from admission across the first 24 h in the ICU in severe TBI patients to develop a patient outcome prediction system.ResultsA feature extraction strategy was applied to measure the HRV fluctuation during time. A prediction model was developed based on HRV measures with a genetic algorithm for feature selection. The result (AUC: 0.77) was compared with earlier reported scoring systems (highest AUC: 0.76), encouraging further development and practical application.ConclusionsThe prediction models built with different feature sets indicated that HRV based parameters may help predict brain injury patient outcome better than the previously adopted illness severity scores.

Heart Rate Variability Responses to a Training Cycle in Female Youth Rowers.

Heart rate variability (HRV) is a reputable estimate of cardiac autonomic function used across multiple athletic populations to document the cardiac autonomic responses to sport demands. However, there is a knowledge gap of HRV responses in female youth rowers. Thus, the purpose of this study was to measure HRV weekly, over a 15-week training period, covering pre-season and up to competition in youth female rowers, in order to understand the physiological response to long-term training and discern how fluctuations in HRV may relate to performance in this population. Measures of heart rate and heart rate variability were recorded before training each Friday over the monitoring period in seven athletes. Analysis of heart rate variability focused on time domain indices, the standard deviation of all normal to normal R–R wave intervals, and the root mean square of successive differences as markers of cardiac parasympathetic modulation. Training load was quantified by multiplying the rating of perceived exertion of the weeks training and training duration. A decrease was identified in cardiac parasympathetic modulation as the season progressed (Effect Size (Cohen’s d) = −0.34 to −0.8, weeks 6 and 11–15), despite no significant relationship between training load and heart rate variability. Factors outside of training may further compound the reduction in heart rate variability, with further monitoring of external stressors (e.g., school) in adolescent athletes.

Autonomic Nervous System Disorder Due to Exposure RF Jamming

Background: The study of Heart rate is very important the body heart is directly related to heart rate ,the autonomic cardiovascular examination provides necessary information about function of the autonomic nervous system as well functional capacities of effectors heart and vessels and other associated part with radiation . Objective: To study the effect of jammer on autonomic nervous system as measured by heart rate. Patients and Methods: Heart rates of 10 males (age 21-51 years), and 10 females (age 20-54 years) were measured and recorded before, during using jammer for 15 minutes, 30 minutes, and 45 minutes, and one hour after shutting down the device . Results: The results clearly indicate that jammer radiation induced high fluctuations in heart rate variability of recovery period (after15 minutes using jammer) and show that the change of heart rate variability signal during jammer exposure is not permanent. There was no statistically significant difference observed in heart rate. Conclusion: The heart rate flection resulting from exposure to radiofrequencies of jammer are depending on the orientation of both electric &magnetic field of the electromagnetic radiation, the greater increase in heart rate that occurred during E orientation irradiation.

Influence of violations of autonomic regulation on the development of occupational polyneuropathy of the upper extremities in Kuzbass miners

Introduction.Active coal mining in Kuzbass, with its unfavorable climatic and environmental conditions, necessitates the study of occupational diseases of workers in this industry. One of the most common occupationally caused diseases of miners is polyneuropathy of the upper extremities.The aim of the studyis to assess the effect of autonomic disorders on the course of occupational upper limb polyneuropathy in workers of the Kuzbass coal industry using various methods of analyzing heart rate variability.Materials and methods. 52 employees of coal enterprises aged from 43 to 64 years with the established diagnosis of “polyneuropathy of the upper extremities” were examined. The control group consisted of 16 healthy volunteers of the same age, engaged mainly in mental or light physical labor. Electroneuromyography was performed to assess the degree of damage to peripheral nerve fibers. Spectral and nonlinear parameters of heart rate variability were used to determine the state of autonomic regulation. The Mann-Whitney criterion was used to assess the statistical significance of differences between the study groups.Results.3 groups of patients with polyneuropathy were identified according to the severity of violations of impulse conduction in the peripheral nerves. In subjects with mild, initial disturbances of pulse conduction (n=8, 15.4%), a decrease in parasympathetic influence is determined, which is manifested by a statistically significant decrease in the power of high frequency oscillations of the heart rate variability spectrum. With moderate signs of polyneuropathy (28 cases, 53.9%), there is a shift in the autonomic balance towards sympathetic activation; a statistically significant increase in very low-frequency fluctuations in heart rate variability indicates an increase in the influence of suprasegmental autonomic centers. In subjects with gross violations of the peripheral nerve impulses (n=16, 30.7%), there is a decrease in the power of oscillations in all frequency ranges of heart rate variability.Conclusions. The obtained data confirm the influence of autonomic regulation on the course of occupational polyneuropathy.The authors declare no conflict of interests.

Daily Resting Heart Rate Variability in Adolescent Swimmers during 11 Weeks of Training.

Adolescent athletes are particularly vulnerable to stress. The current study aimed to monitor one of the most popular and accessible stress markers, heart rate variability (HRV), and its associations with training load and sleep duration in young swimmers during an 11-week training period to evaluate its relevance as a tool for monitoring overtraining. National-level swimmers (n = 22, age 14.3 ± 1.0 years) of sprint and middle distance events followed individually structured training programs prescribed by their swimming coach with the main intention of preparing for the national championships. HRV after awakening, during sleep and training were recorded daily. There was a consistent ~4.5% reduction in HRV after 3–5 consecutive days of high (>6 km/day) swimming volume, and an inverse relationship of HRV with large (>7.0 km/day) shifts in total training load (r = −0.35, p < 0.05). Day-to-day HRV did not significantly correlate with training volume or sleep duration. Taken together, these findings suggest that the value of HRV fluctuations in estimating the balance between the magnitude of a young athlete’s physical load and their tolerance is limited on a day-to-day basis, while under sharply increased or extended training load the lower HRV becomes an important indicator of potential overtraining.

A novel method of heart rate variability measurement

The complex fluctuation of heart rate variability reflects the autonomous regulation function of the heart. In this paper, a novel method of measuring the heart rate variability is proposed. Firstly, the heart rate variability signal is decomposed by the improved complete ensemble empirical mode decomposition with adaptive noise method, and the multiple intrinsic mode functions are obtained, and the bubble entropy of each intrinsic mode function is calculated to obtain an entropy value vector. Then, the vector is mapped to a network based on a limited penetrable horizontal visibility graph method. By calculating various characteristic parameters of the network, the coupling relationship between the nonlinear features of heart rate variability in different time-frequency scale states are studied. The characteristic parameters include mean value of aggregation coefficient (MC), the characteristic path length (CL), the topological entropy of network (TE), the network level weighted bubble value (WB), and the pseudo mean value of node weight (PW). Firstly, the heart rate variabilities of 29 patients with congestive heart failure and 29 normal sinus heart rhythm subjects are analyzed by time domain, frequency domain and ICBN analysis method, the &lt;i&gt;T&lt;/i&gt; test is used for statistical analysis, and Fisher discriminant method is used for classification. The results show that the time domain triangular index HRVTI, frequency domain index LF/HF, WB, PW and CL in ICBN have statistical differences. The accuracy rate of recognition model based on WB, CL, frequency domain index LF/HF and Fisher discriminant method is 89.66%. Secondly, the heart rate variabilities of 43 patients with atrial fibrillation arrhythmia and another 43 normal sinus heart rhythm subjects are analyzed by the same methods, including the time domain analyzed method, frequency domain analyzed method, and ICBN analyzed method. Then, the T test is also used for statistical analysis, and Fisher discriminant method is used for classification. The results show that using the time domain index pNN5 and RMSSD, frequency index LF/HF, ICBN index WB and PW as the feature vectors, and the Fisher discriminant mode as the classifier, the accuracy rate of recognition for atrial fibrillation arrhythmia is 91.86%. From these results it is concluded that the ICBN method provides a new idea for the heart rate variability measurement.