Autonomic Modulation Of Heart Rate Research Articles

Early detection of cardiac autonomic dysfunction using the respiratory sinus arrhythmia accentuation maneuver in patients with stage B1 of Chagas Disease

Introduction: The maneuver to accentuate respiratory sinus arrhythmia (RSA) demonstrates to be a convenient instrument to evaluate the autonomic modulation of individuals with chronic Chagas disease cardiomyopathy (CCC), even with medication influence, as T-cruzi causes an inflammatory process creating lesions in the cardiac nerve endings of patients affected by Chagas disease. Objective: To evaluate the autonomic modulation of heart rate (HR) at rest and during the respiratory sinus arrhythmia accentuation maneuver (RSA-M) in patients with CCC in stage B1. Methods: thirty-six individuals were evaluated, divided into the CCC group, composed of 18 patients with Chagas heart disease, and the control group, formed by 18 healthy individuals. Heart rate variability (HRV) was collected beat by beat using the electrocardiography system Wincardio USB, supine for 10 minutes, and during the RSA-M for 6 minutes. Results: We observed higher values of statistical significance in Control group for mean HR (p = 0.005), IRR (p = 0.007), and worse autonomic adjustments related to SD2 / SD1 (p = 0.001) concerning CCC group in a supine position. However, evaluating the RSA-M, we observed a statistical difference in the delta I-E (p = 0,039) and the E / I rate (p = 0.045) of the Control group in relation to the CCC group. Conclusion: Patients with CCC showed better cardiovascular condition and HR control compared to the group of healthy individuals at rest. However, when subjected to RSA-M, the results showed a reduction in vagal balance in the autonomic control of individuals with CCC. Keywords: respiration; heart rate; chagas cardiomyopathy; autonomic nervous system diseases.

Characterization of heart rate variability in end-stage renal disease patients after kidney transplantation with recurrence quantification analysis.

Heart rate variability (HRV) is a noninvasive approach to studying the autonomic modulation of heart rate in experimental settings, such as active standing sympathetic stimulation. It is known that patients with end-stage renal disease during active standing have few changes in HRV dynamics, which are improved after hemodialysis. However, it is unknown whether the response to active standing is recovered after definitive treatment with kidney transplantation. This work aims to assess the change in HRV dynamics in the supine position and active standing through time and frequency-based metrics, as well as recurrence plot quantitative analysis (RQA). We studied HRV dynamics by obtaining 5-minute electrocardiographic recordings from kidney transplant recipients who underwent an active standing test. The mean duration of heartbeats and their standard deviation diminished in active standing, compared with the supine position. Also, the low-frequency component of HRV and the presence of diagonal and vertical structures in RQA were predominant. A larger estimated glomerular filtration rate was significantly correlated with broader HRV in the supine position and during active standing. The narrower HRV during active standing may indicate a sympathetic response to external stimuli, which is expected in a functional cardiovascular system, and may be influenced by renal function.

Chronic effect of resistant physical exercise on linear and nonlinear dynamics of heart rate variability in patients with type 2 diabetes mellitus

Introduction: Diabetes Mellitus (DM) can promote changes in the autonomic nervous system. Training with resistance exercise can contribute to the decrease of the glycemic level and improve the neural control of the heart. Objective: to verify the effects of resistance exercise training (RT) on linear and non-linear dynamics of autonomic heart rate (HR) modulation in patients with DM2. Methods: Eight patients with DM2 were studied. The R-R intervals of the HR were recorded in the supine resting condition and HRV was analyzed by linear and non-linear method. RT was performed for 12 weeks, with 60% 1RM, 5 exercises for large muscle groups. Results: data variations between post-RT and initial ones did not show statistical difference (p>0.05) in HRV calculated both by linear and non-linear methods. Conclusion: 12 weeks of moderate RT does not promote positive effects on HRV in patients with T2DM.

Early mobilization in children with pneumonia in mechanical ventilation: randomized clinical trial

Immobility in the bed of pediatric patients in intensive care units increases the risk of morbidities such as pneumonia, with consequences for autonomic function. Physiotherapy based on physical exercise is part of the rehabilitation process and can modify autonomic function. To compare the effects of two physical therapy protocols, one conventional and the other based on physical exercise, on heart rate variability, length of stay and invasive mechanical ventilation in children with ventilator-associated pneumonia. This is a randomized clinical trial, the volunteers were divided into a control group (submitted to a physiotherapy protocol with only breathing exercises and passive mobilization) and an experimental group (submitted to a physiotherapy protocol based on physical exercise). Patients aged 1 to 8 years, on invasive mechanical ventilation, with pneumonia were included. The rehabilitation protocol took place for 4 consecutive days. The collection of heart rate variability occurred in the pre-protocol period, on the 2nd day, 1 day after the end of the protocol. 25 patients completed the study. There was a reduction in the time of invasive mechanical ventilation in the experimental group (p = 0.01). There was an improvement in the heart rate variability of the experimental group in all indices (p < 0.01). The post-protocol analysis of the groups showed significant values in all variables (p < 0.05). Exercise-based physical therapy protocol improved autonomic heart rate modulation and reduced IMV time in children with ventilator-associated pneumonia.

Effect of transauricular nerve stimulation on perioperative pain: a single-blind, analyser-masked, randomised controlled trial

BackgroundActivation of central autonomic pathways, including those regulating the arterial baroreflex, might reduce acute pain. We tested the hypothesis that transcutaneous auricular nerve stimulation (TAN) reduces pain after orthopaedic trauma surgery through autonomic modulation. MethodsA total of 86 participants aged >18 yr were randomly assigned to 50 min of either sham or active bilateral TAN, undertaken before, and again 24 h after, surgery for orthopaedic trauma. The primary outcome was absolute change in pain 24 h postoperatively, comparing the 100 mm visual analogue scale (VAS) before and after TAN. Secondary outcomes included the minimal clinically important difference in pain (>10 mm increase or reduction in VAS) before/after surgery, using intention-to-treat analysis. Holter monitoring, the analysis of which was masked to allocation, quantified autonomic modulation of heart rate. ResultsFrom June 22, 2021 to July 7, 2022, 79/86 participants (49 yr; 45% female) completed TAN before and after surgery. For the primary outcome, the mean reduction in VAS was 19 mm (95% confidence interval [CI]: 12–26) after active TAN (n=40), vs 10 mm (95% CI: 3–17) after sham TAN (n=39; P=0.023). A minimally clinically important reduction in postoperative pain occurred in 31/40 (78%) participants after active TAN, compared with 15/39 (38%) allocated to sham TAN (odds ratio 5.51 [95% CI: 2.06–14.73]; P=0.001). Only active TAN increased heart rate variability (log low-frequency power increased by 0.19 ms2 [0.01–0.37 ms2]). Prespecified adverse events (auricular skin irritation) occurred in six participants receiving active TAN, compared with two receiving sham TAN. ConclusionBilateral TAN reduces perioperative pain through autonomic modulation. These proof-of-concept data support a non-pharmacological, generalisable approach to improve perioperative analgesia.

Cardiac Behavior and Heart Rate Variability in Elderly Hypertensive Individuals during Aerobic Exercise: A Non-Randomized Controlled Study.

High blood pressure is an important public health problem due to its high prevalence, the difficulty to control it, and its high contribution to morbidity. A series of changes may be linked to the aging process, compromising cardiac conduction, and reducing cardiovascular baroreceptor function. Advancing age promotes a decline in heart rate variability and this decrease can increase the probability of cardiovascular disease. The aim of this study was to analyze the autonomic modulation of heart rate in hypertensive elderly individuals during and after a session of aerobic exercise, and to compare it with elderly individuals without cardiovascular or metabolic disease. Our study was a non-randomized controlled study with hypertensive elderly (HBP group) and elderly without cardiovascular and/or metabolic diseases (control group). Data on blood pressure and heart rate variability (HRV) were collected before, during, and after 30 min of aerobic physical exercise on a treadmill. There was a reduction in HF (ms2) and SD1 (ms) in the 5 min of recovery for the elderly in the control group. The elderly in the control group also had greater RMSSD and SD1 30 min post-exercise when compared to the initial mins of recovery. We concluded that there was no difference in autonomic modulation and global heart rate variability between elderly individuals without cardiovascular and metabolic diseases and hypertensive individuals after a bout of aerobic exercise. Elderly individuals without metabolic diseases showed a decrease in parasympathetic modulation and global variability between the time of rest and 5 min of recovery. However, up to 30 min of post-exercise recovery, they restored parasympathetic activity.

Autonomic heart rate modulation in patients with coronavirus disease 2019 in mechanical ventilation.

Patients with coronavirus disease 2019 on automatic mechanical ventilation have greater heart rate modulation with greater parasympathetic modulation. To analyze the autonomic modulation of heart rate in critically ill patients with coronavirus disease 2019 on invasive mechanical ventilation. A cross-section study was carried out with 36 individuals divided into two groups. The control group included patients of both genders, in orotracheal intubation with invasive mechanical ventilation under controlled assisted mode, hospitalized in the intensive care unit for another 24 h. In the non-COVID group, patients diagnosed with coronavirus disease 2019 in the same condition mentioned in the control group. There was a significant increase in heart rate variability (standard deviation of all normal RR intervals recorded at an interval of time; p=0.001; triangular interpolation histogram of RR intervals; p=0.048; and SD2; p=0.014) in the coronavirus disease group compared to the non-COVID group. Successively, the parameters that demonstrate parasympathetic modulation are shown to be higher in the group of patients with coronavirus disease 2019 (root mean square of the square of differences between adjacent normal RR intervals in an interval of time; p<0.001; pNN50; p<0.001; SD1; p=0.002; and high frequency; p=0.022). There was a greater autonomic modulation of heart rate with a greater parasympathetic modulation in patients with coronavirus disease 2019 on mechanical ventilation.

Effects of Psidium guajava L. leaves extract on blood pressure control and IL-10 production in salt-dependent hypertensive rats

Psidium guajava (guava) leaves extract displays anti-hypertensive properties by mechanisms not yet fully understood. Here, we investigated whether sympathetic drive and immune signaling mechanisms are involved with the antihypertensive effect of the guava extract in a model of salt-dependent hypertension. Raw guava extract (rPsE) was characterized by colorimetric and UPLC-MS techniques. Two doses of rPsE (100 and 200 mg/kg) were evaluated for anti-hypertensive effect using a suspension system (PsE). Weaned male Wistar rats were put on a high-salt diet (HSD, 0.90 % Na+) for 16 weeks and received gavages of PsE for the last 4 weeks. Blood pressure (BP) was measured at the end of treatment in conscious rats. The neurogenic pressor effect was assessed by ganglionic blockade with hexamethonium. Autonomic modulation of heart rate was evaluated by spectral analysis. The effects of orally administered PsE on lumbar sympathetic nerve activity (LSNA) were assessed in anesthetized rats. Blood IL-10, IL-17A, and TNF were measured. The increased neurogenic pressor effect of HSD rats was reduced by PsE 100 mg/kg, but not by 200 mg/kg. PsE (200 mg/kg) administration in anesthetized rats produced a greater fall in BP of HSD rats compared to standard salt diet (SSD) rats. PsE hypotensive response elicited an unproportionable increase in LSNA of HSD rats compared to SSD rats. PsE (200 mg/kg) increased plasma concentrations of IL-10 but had no effect on TNF or IL-17A. Our data indicate that the antihypertensive effects of PsE may involve autonomic mechanisms and immunomodulation by overexpression of IL-10 in salt-dependent hypertensive rats.

Physical Exercise Affects Quality of Life and Cardiac Autonomic Modulation in Patients With Chronic Kidney Failure Submitted to Hemodialysis: A Randomized Clinical Trial.

Performing physical exercise during hemodialysis has been debated regarding safety and efficacy for improving life quality for patients with chronic kidney disease (CKD). Thus, we explored the influence of physical exercise during hemodialysis on both autonomic modulation of heart rate and quality of life for patients with CKF in a randomized clinical trial. We randomly allocated participants requiring hemodialysis to an experimental exercise group (EG) and a control no-exercise group (CG) and assessed their quality of life with the Kidney Disease Quality of Life Short Form-KDQOL-SF™ 1.3 and with Polar RS800CX to monitor their heart rate variability (HRV) before and threemonths after the end of the exercise intervention. EG participants reported a significant increase in their quality of life (p = .05, physical function, physical aspects, pain, emotional well-being, emotional function; p = .03, energy and fatigue) and showed HRV improvement (p = .05, RMSSD, SDNN, and SD2; p = .004, SD1) after threemonths of exercise. Thus, we recommend supervised physical exercise during hemodialysis for carefully selected patients.

Influence of daytime blue-enriched bright light on heart rate variability in healthy subjects

ABSTRACT Heart rate variability (HRV), the indicator of the autonomic nervous system-induced modulation of heart rate, is a focal topic in psychophysiological research. The effect of indoor light on HRV may be related to various psychophysiological functions. The current study (N = 20) examined the response of the autonomic nervous system (ANS) to bright vs. dim blue-enriched light (1200 lx or 200 lx at eye level, 6500 K) exposure for five hours in the afternoon among healthy young adults. The results revealed a significant main effect of light condition on the time-domain indicators, with the significantly higher HRV (SDNN and RMSSD) under 200 lx versus 1200 lx condition, and the same case was revealed for the standard deviations of the Poincaré plot in non-linear effects. Conversely, no significant effects were revealed for the frequency- domain indicators of HRV measured with the subjects’ eyes open. These findings suggested that the autonomic nervous system modulation of HRV was stronger under bright light conditions.

Measuring the Rate of Information Exchange in Point-Process Data With Application to Cardiovascular Variability.

The amount of information exchanged per unit of time between two dynamic processes is an important concept for the analysis of complex systems. Theoretical formulations and data-efficient estimators have been recently introduced for this quantity, known as the mutual information rate (MIR), allowing its continuous-time computation for event-based data sets measured as realizations of coupled point processes. This work presents the implementation of MIR for point process applications in Network Physiology and cardiovascular variability, which typically feature short and noisy experimental time series. We assess the bias of MIR estimated for uncoupled point processes in the frame of surrogate data, and we compensate it by introducing a corrected MIR (cMIR) measure designed to return zero values when the two processes do not exchange information. The method is first tested extensively in synthetic point processes including a physiologically-based model of the heartbeat dynamics and the blood pressure propagation times, where we show the ability of cMIR to compensate the negative bias of MIR and return statistically significant values even for weakly coupled processes. The method is then assessed in real point-process data measured from healthy subjects during different physiological conditions, showing that cMIR between heartbeat and pressure propagation times increases significantly during postural stress, though not during mental stress. These results document that cMIR reflects physiological mechanisms of cardiovascular variability related to the joint neural autonomic modulation of heart rate and arterial compliance.

THE EFFECT OF PILATES METHOD OF AUTONOMIC MODULATION IN OLDER WOMEN

Abstract Objective: To verify the effects of the Pilates compared to Resistance method on autonomic modulation of heart rate of older women. Design and method: Twenty-four older women (60 to 80 y.o.) submitted to resistance training, W (RT, n = 12) or Pilates (PT, n = 12) for 12 weeks, twice a week, one hour per session. Physical evaluation was performed at the beginning (week 0, RT0 and PM0) and the end of training protocols (week 12, RT12 and PM12), to analyse body composition (bioimpedance, X-ray emission densitometry), and unipodal balance, hand grip strength, functional mobility (Timed Up and Go test–TUGT). Pulse pressure was obtained by using Finometer, and spectral analysis was performed by using Heartscoope Software to obtain normalized high frequency component (RRHFn), normalized low frequency component (RRLFn), LF/HF ratio, baroreflex sensitivity (BRS), harte rate (HR), diastolic blood pressure mean (DAP), and systolic blood pressure mean (SAP). Statistical analysis was performed by two-way ANOVA. Results: observed an improve of unipodal balance in both groups (RT1 = 12,9 ± 8 s vs. RT12 = 24,8 ± 8,4 s and PT1 = 8,6 ± 2,5 s vs. PT12 = 22 ± 9,23 s). Pilates was able to improve TUGT (PT1 = 5,5 ± 1.6 s vs. PT12 = 2,9 ± 0,5 s). No chances in body composition and hand grip strength were observed. Bood pressure evaluation showed no changes in RT (DAP 84.05 ± 10 and SAP: 135 ± 18mmHg) and PT (DAP 73.6 ± 8 and SAP: 135 ± 14mmHg); HR (RT: 62.7 ± 6 and PT: 60.1 ± 3 bpm) and BRS were also unchanged after training. Spectral analysis shows a decrease, but non significant, in RT of RRLFn (-14,6%) and RR LF/HF (-27,3%). Interstingly, RRHFn increased significantly (+27,3%). On the other hands, PT presented a significant decrease of RRLFn (-36,2%), RR LF/HF (-55,6%) and an increase of RRHFn (+33,9%). Conclusions: Both exercise protocols were effective to improve physical capacity, but Pilates method was also efficient to improve TUGT. Both methods were able to increase HF (parasimpathetic modulation). However, Pilates was also efficient to reduce LF, indicating a reduction of sympathetic modulation, combined to the increase of parasympathetic activity on the heart. The improve of autonomic modulation indicate a better efficiency to reduce cardiovascular risk.

Differences in autonomic heart rate modulation during rest and after a supramaximal anaerobic test in relation to gender and the menstrual cycle in women

Background/Aim. Heart rate variability (HRV) and heart rate recovery (HRR) show differences between genders, and dissimilarities were also reported in women in various menstrual cycle (MC) phases. The aim of this research was to analyze cardiac autonomic indices during rest and in re-covery after the Wingate test between genders in the young, sedentary population and to investigate whether a MC phase in women can influence these indi-ces. Methods. Twenty-five females (20.5 ? 0.7 years) and sixteen males (20.4 ? 0.7 years) performed the Wingate anaerobic test on a cycle ergometer while their HRR and resting and recovery HRV indices were obtained. In fe-males, data were collected during three distinctive MC phases. Results. The natural logarithm of low-frequency (lnLF) HRV marker and the natural logarithm of high-frequency (lnHF) HRV marker were higher in males dur-ing rest compared to women in all MC phases, except in the late follicular phase, where no differences in lnHF be-tween genders were observed. Markedly higher lnLF and lnHF were recorded in males after the Wingate test. There were no differences in HRV between women in various MC phases during rest. Surprisingly, parasympathetic time-domain marker (the square root of the mean squared dif-ferences of successive NN intervals, RMSSD) and lnLF were both higher in the early follicular phase in compari-son to the luteal phase of MC during recovery. HRR was faster in men in comparison to women in all MC phas-es. Conclusion. Males show greater HRR and total varia-bility during rest and recovery, but it appears that resting parasympathetic activity is similar when females are in the late follicular phase of MC. Intra-female resting autonomic variability is not affected by the sex hormonal cycle. Post-exercise HRV in the early follicular phase reflects a signifi-cantly favourable autonomic profile in comparison to the luteal phase of MC.

Effect of air pollution on the autonomic modulation of heart rate in overweight adults.

ABSTRACTObjective:To analyze the effect of air pollution on heart rate variability in overweight individuals.Methods:A total of 46 adult individuals, both sexes, aged between 18 and 49 years and with body mass index >25kg/m2 were analyzed. All volunteers were students from public schools of two cities in the state of São Paulo. The clinical, demographic and anthropometric data of each individual, as well as heart rate variability through time domain, geometric and frequency indices were collected. For the air quality analysis, the following variables were investigated: concentration of carbon dioxide, particulate matter, temperature and relative humidity. The analysis was carried out with descriptive and analytical statistics, adopting a level of significance of 5%.Results:There was a reduction in overall heart rate variability in overweight individuals by the following indices: mean standard deviation of all normal RR intervals, long-term standard deviation of continuous RR intervals, ratio of short-and long-term standard deviation of continuous RR intervals. In addition, the indices responsible for parasympathetic control showed a downward trend in their values, as well as the low frequency index, which represented sympathetic action, although not significant.Conclusion:Overweight individuals exposed to air pollution had lower heart rate variability than the Control Group.

Evaluation of autonomic modulation of lung function and heart rate in children with cystic fibrosis.

The autonomic nervous system (ANS) plays an important role in modulating bronchial smooth muscle contractility, which is altered in cystic fibrosis (CF). A convenient approach to probe ANS regulation is the quantitative analysis of heart rate variability (HRV). The purpose of this study was to evaluate ANS regulation in children with CF and to investigate the influence of colonization by Pseudonomas aeruginosa via assessment of HRV in colonized CF (CCF) children and noncolonized CF (NCCF) children. Sixteen children with CF (7 CCF and 9 NCCF) and seven healthy age-matched control children were enrolled in the study. Heart rate was recorded for 10 min at rest in the supine and standing positions and HRV analysis was carried out using autoregressive spectral analysis. The CCF group was characterized by lower forced expiratory volume than NCCF, indicating an impairment of respiratory function. The HRV parameters further confirmed the possible sympathetic overactivity in CCF. Children with CF exhibited hyperactivity of the sympathetic nervous system. In particular, the CCF group presented a greater impairment of ANS modulation. Both CCF and NCCF children showed lower supine vagal activation in the HRV indices related to sympathetic activation and reduction of indices indicating vagal activity with the postural change from supine to standing when compared to the NCCF group.

Heart rate variability in frontal lobe epilepsy: Association with SUDEP risk.

Frontal lobe epilepsy (FLE) may impair autonomic heart rate modulation. Decreased heart rate variability (HRV) may enhance risk of sudden death. Our objective was to describe whole day and wakefulness/sleep HRV parameters from FLE patients in comparison with those of healthy controls and correlate HRV parameters to SUDEP-7 scores. Ten patients with FLE and 15 healthy controls underwent a 24-hour electrocardiogram holter. The SUDEP-7 score was calculated for patients. Subgroups were identified according to active epilepsy, number of generalized seizures, cognitive deficit, medication load, and time-length of epilepsy. Time-domain SDNN, SDNNi, SDANN, rMSDD, and pNN50 and frequency-domain LF, HF, and LF/HF parameters were analyzed. Wilcoxon and Spearman correlation tests were used. A P<.05 was considered significant. Patients SDNN, SDNNi, rMSSD, and pNN50 were decreased in 24-hour recordings. Although a tendency for a protective effect of sleep was seen for both patients and controls, intragroup comparisons of sleeping/waking states revealed a significant increase in sleep rMSSD (P=.046) and pNN50 (P=.041) only for controls. All 24-hour time-domain parameters and LF were inversely and significantly correlated to SUDEP-7, particularly SDANN (ρ=-0.896, P=.00019), known to deteriorate with diminished physical activity and decreased in patients with more generalized seizures. Wakefulness parameters did not correlate to SUDEP-7, whereas correlations to sleep parameters were very strong, particularly with rMSSD (ρ=-0.945, P=.00012). Cognitive deficit was associated with decreased pNN50, sleep pNN50, and LH. HRV is impaired in patients with FLE. Low HRV scores are associated with increased risk for SUDEP as measured by the SUDEP-7 score.

The Advantage of Supine and Standing Heart Rate Variability Analysis to Assess Training Status and Performance in a Walking Ultramarathon.

Cardiac autonomic modulation of heart rate, assessed by heart rate variability (HRV), is commonly used to monitor training status. HRV is usually measured in athletes after awakening in the morning in the supine position. Whether recording during standing reveals additional information compared to supine remains unclear. We aimed to evaluate the association between short-duration HRV, assessed both in the supine and standing position, and a low-intensity long-duration performance (walking ultramarathon), as well as training experience. Twenty-five competitors in a 100 km walking ultramarathon underwent pre-race supine (12 min) and standing (6 min) HR recordings, whereas performance and subjective training experience were assessed post-race. There were no significant differences in both supine and standing HRV between finishers (n = 14) and non-finishers (n = 11, mean distance 67 km). In finishers, a slower race velocity was significantly correlated with a higher decrease in parasympathetic drive during position change [larger decrease in High Frequency power normalized units (HFnu: r = −0.7, p = 0.01) and higher increase in the detrended fluctuation analysis alpha 1 index (DFA1: r = 0.6, p = 0.04)]. Highly trained athletes accounted for higher HFnu during standing compared to poorly trained competitors (+11.5, p = 0.01). Similarly, greater training volume (total km/week) would predict higher HFnu during standing (r = 0.5, p = 0.01). HRV assessment in both supine and standing position may provide additional information on the dynamic adaptability of cardiac autonomic modulation to physiologic challenges and therefore be more valuable for performance prediction than a simple assessment of supine HRV. Self-reported training experience may reliably associate with parasympathetic drive, therefore indirectly predicting long-term aerobic performance in ultramarathon walking races.

Features of autonomous regulation in young subjects with increased vestibular analyzer sensitivity

Introduction: Each person's body have adaptation during the load due to different changes in the cardiovascular system. One of the first systems that responds to any factors and is actively involved in the processes of adaptation is the autonomic nervous system. It is known that as a result of excitement of the vestibular analyzer kinetosis develops - "motion sickness", which is accompanied by nausea, dizziness, unsteadiness of gait, general weakness. In this regard, assessment of the functional state of the body and its adaptive reserves continues to be one of the most important problems of modern physiology and medicine.The purpose of the study was to evaluate the features of autonomous regulation in subjects with increased sensitivity of the vestibular analyzer.Materials and methods: 60 people between the ages of 18-19 were examined. Vestibular sensitivity was determined with a help of questionnaire. The state of the autonomic nervous system was determined by analyzing heart rate variability using a 5-minute ECG registration technique. The registration and recording was performed by the «PolySpectr +» computer program.Results and discussion: Based on the questionnaire, the students were divided into 2 groups: with proper and with increased vestibular sensitivity. In students with proper vestibular sensitivity, the LF / HF ratio of 1.06 indicates a balanced type of autonomic heart rate modulation. The analysis of spectral indices in subjects with increased vestibular sensitivity showed a lower overall power of the spectrum, which indicates less functional reserves of the organism. We set much higher HF waves, which indicates an increase in the activity of the parasympathetic system. This is also indicated by the LF / HF ratio of 0.59. When considering the rhythmograms of subjects with increased vestibular sensitivity, 64% of 1-st grade rhythmograms, 20% of 2-nd grade rhythmograms and 16.6% of 3-rd grade rhythmograms were registered. When assessing rhythmograms of the 3-rd class, it can be concluded that the level of functional reserves of subjects with increased sensitivity of the vestibular analyzer can be reduced, which may lead to a decrease in the adaptive capacity of these subjects.Conclusions: In subjects with increased vestibular sensitivity, the parasympathetic autonomic nervous system makes the greatest contribution to the regulation of cardiac rhythm.

Geometric indexes of heart rate variability in healthy individuals exposed to long-term air pollution.

The aim of this study was to investigate the autonomic modulation of heart rate in healthy individuals exposed to long-term air pollution through geometric methods. We analyzed data from 109 healthy adults aged 18 to 49, divided into three groups according to the exposure time: period 0 to 15years of exposure (n = 29), more than 15years of exposure (n = 31), and control group (n = 49). For the analysis of heart rate variability (HRV), heart rate was recorded beat-to-beat for 20min in the sitting position. The RR intervals were transformed into geometric indexes, and from them, we calculated the RRTri (triangular index), TINN (triangle interpolation of histogram of intervals NN), and Poincaré plot (SD1, SD2, and SD1/SD2). Significantly lower values were observed in the group of individuals exposed to air pollution for more than 15years compared with the group of individuals exposed to air pollution for a period of 0-15years and those not exposed for the RRTri (11.5 vs 13.8 vs 14.0), SD1 (16.4 vs 20.5 vs 20.6), SD2 (60.5 vs 68.1 vs 72.5), and SD1/SD2 (0.27 vs 0.34 vs 0.31), with the effect of this difference being considered large (RRTri), medium (SD1, SD1/SD2), and small (SD2). TINN was not significantly different among groups (198.2 vs 223.1 vs 233.6). Healthy individuals exposed to air pollution for more than 15years present an autonomic imbalance, characterized by lower parasympathetic modulation and overall HRV.

Acclimation to a thermoneutral environment abolishes age-associated alterations in heart rate and heart rate variability in conscious, unrestrained mice

Mice are among the most widely used translational models of cardiovascular aging and offer a method to quickly assess lifespan changes in a controlled environment. The standard laboratory temperature (20–22 °C), however, imposes a cold stress on mice that causes an increase in sympathetic nervous system–mediated activation of brown adipose tissue (BAT) to maintain a core body temperature of 36–37 °C. Thus, while physiologic data obtained recapitulate human physiology to a certain degree, interpretations of previous research in mice may have been contaminated by a cold stress, due to housing mice below their thermoneutral zone (30 °C). The purpose of this investigation was to examine how chronic sympathetic stimulation evoked by acclimation to 20 °C might obscure interpretation of changes in autonomic modulation of heart rate (HR) and heart rate variability (HRV) that accompany advancing age. HR and HRV before and after administration of a dual-autonomic blockade were measured via in-vivo ECG in young (3 months) and aged (30 months) male C57BL/6 telemetry-implanted mice following temperature acclimation for 3 days at 30 °C or 20 °C. Mean basal and intrinsic HR of both young and aged mice became markedly reduced at 30 °C compared to 20 °C. In both age groups, HRV parameters in time, frequency, and non-linear domains displayed increased variability at 30 °C compared to 20 °C under basal conditions. Importantly, age-associated declines in HRV observed at 20 °C were ameliorated when mice were studied at their thermoneutral ambient temperature of 30 °C. Thus, an accurate understanding of autonomic modulation of cardiovascular functions in mice of advanced age requires that they are housed in a metabolically neutral environment.