Sympathetic-parasympathetic Balance Research Articles

Autonomic dysfunction and treatment strategies in intracerebral hemorrhage.

Autonomic dysfunction with central autonomic network (CAN) damage occurs frequently after intracerebral hemorrhage (ICH) and contributes to a series of adverse outcomes. This review aims to provide insight and convenience for future clinical practice and research on autonomic dysfunction in ICH patients. We summarize the autonomic dysfunction in ICH from the aspects of potential mechanisms, clinical significance, assessment, and treatment strategies. The CAN structures mainly include insular cortex, anterior cingulate cortex, amygdala, hypothalamus, nucleus of the solitary tract, ventrolateral medulla, dorsal motor nucleus of the vagus, nucleus ambiguus, parabrachial nucleus, and periaqueductal gray. Autonomic dysfunction after ICH is closely associated with neurological functional outcomes, cardiac complications, blood pressure fluctuation, immunosuppression and infection, thermoregulatory dysfunction, hyperglycemia, digestive dysfunction, and urogenital disturbances. Heart rate variability, baroreflex sensitivity, skin sympathetic nerve activity, sympathetic skin response, and plasma catecholamine concentration can be used to assess the autonomic functional activities after ICH. Risk stratification of patients according to autonomic functional activities, and development of intervention approaches based on the restoration of sympathetic-parasympathetic balance, would potentially improve clinical outcomes in ICH patients. The review systematically summarizes the evidence of autonomic dysfunction and its association with clinical outcomes in ICH patients, proposing that targeting autonomic dysfunction could be potentially investigated to improve the clinical outcomes.

Multifractal Heart Rate Value Analysis: A Novel Approach for Diabetic Neuropathy Diagnosis.

Type 2 diabetes mellitus (T2DM) is characterized by several complications, such as retinopathy, renal failure, cardiovascular disease, and diabetic neuropathy. Among these, neuropathy is the most severe complication, due to the challenging nature of its early detection. The linear Hearth Rate Variability (HRV) analysis is the most common diagnosis technique for diabetic neuropathy, and it is characterized by the determination of the sympathetic-parasympathetic balance on the peripheral nerves through a linear analysis of the tachogram obtained using photoplethysmography. We aimed to perform a multifractal analysis to identify autonomic neuropathy, which was not yet manifest and not detectable with the linear HRV analysis. We enrolled 10 healthy controls, 10 T2DM-diagnosed patients with not-full-blown neuropathy, and 10 T2DM diagnosed patients with full-blown neuropathy. The tachograms for the HRV analysis were obtained using finger photoplethysmography and a linear and/or multifractal analysis was performed. Our preliminary results showed that the linear analysis could effectively differentiate between healthy patients and T2DM patients with full-blown neuropathy; nevertheless, no differences were revealed comparing the full-blown to not-full-blown neuropathic diabetic patients. Conversely, the multifractal HRV analysis was effective for discriminating between full-blown and not-full-blown neuropathic T2DM patients. The multifractal analysis can represent a powerful strategy to determine neuropathic onset, even without clinical diagnostic evidence.

The Heart's Function as a Pump Assessed via Impedance Cardiography and the Autonomic System Balance in Patients with Early-Stage Acromegaly.

Acromegaly is a rare, chronic disease that involves structural and functional abnormalities of the cardiovascular system. Acromegaly likely affects interactions between the cardiovascular system and the autonomic nervous system (ANS). Therefore, assessing the relationship between sympathetic-parasympathetic balance by analyzing heart rate variability (HRV) and the hemodynamic profile via impedance cardiography (ICG) may be useful in learning the exact nature of interactions between the ANS and the cardiovascular system. The purpose of this study was to assess a possible association between HRV and ICG-based parameters of cardiac function in patients newly diagnosed with acromegaly. This observational cohort study was conducted on 33 patients (18 men, mean age of 47 years) newly diagnosed with acromegaly and no significant comorbidities. A correlation analysis (Spearman's rank coefficient R) of the parameters assessed via ICG and the HRV assessed via 24 h ambulatory electrocardiography was performed. ICG assessments included the following parameters: stroke volume index (SI), cardiac index (CI), acceleration index (ACI), velocity index (VI), and Heather index (HI). The analysis of HRV included both time-domain parameters (pNN50, SDNN, SDSD, rMSSD) and frequency-domain parameters (total power (TP) and its individual frequency bands: low-frequency (LF day/night), high-frequency (HF day/night), and the LF/HF ratio (day/night)). Frequency-domain HRV analysis showed the following correlations: (1) lower nighttime LF values with higher ACI (R = -0.38; p = 0.027) and HI (R = -0.46; p = 0.007) values; (2) higher nighttime HF values with higher ACI (R = 0.39; p = 0.027) and HI (R = 0.43; p = 0.014) values; (3) lower nighttime LF/HF values with higher ACI (R = -0.36; p = 0.037) and HI (R = -0.42; p = 0.014) values; (4) higher nighttime TP values with higher SI values (R = 0.35; p = 0.049). Time-domain parameters of HRV showed a significant correlation only between the nighttime values of SDSD and SI (R = 0.35; p = 0.049) and between the daytime and nighttime values of SDNN and HR (R = -0.50; p = 0.003 and R = -0.35; p = 0.046). In multivariate regression, only ACI was revealed to be independently related to HRV. In patients newly diagnosed with acromegaly, the relationship between the sympathetic-parasympathetic balance assessed via HRV and the hemodynamic profile assessed via ICG was revealed. Better function of the left ventricle was associated with a parasympathetic shift in the autonomic balance.

Effects of intermittent pneumatic compression on the recovery of cardiovascular parameters after repeated sprint exercise

PurposeIntermittent pneumatic compression (IPC) applies gradual pressure to facilitate lymph and blood flow movement to reduce exercise-induced tissue fluid accumulation and plasma volume loss. This study aimed to evaluate the cardiovascular system response during the recovery with IPC compared with passive recovery (Sham).MethodsSixteen volunteers (7 females and 9 males) executed a cycling-based exhausting sprint interval exercise (8 × 20 s all out), followed by a 30-min IPC or Sham condition. Participants performed two trials in a randomised, counterbalanced, and crossover design. Several cardiovascular parameters (blood pressure, heart function, and peripheral vascular resistance) were recorded at baseline (5ʹ), through the recovery protocol (30ʹ), and afterwards (5ʹ).ResultsThe use of IPC during the recovery phase led to a faster recovery, stated in relative values to pre-exercise, in mean blood pressure (102.5 ± 19.3% vs. 92.7 ± 12.5%; P < 0.001), and cardiac output (139.8 ± 30.0% vs. 146.2 ± 40.2%; P < 0.05) in comparison to Sham condition. Furthermore, during the IPC-based recovery, there was a slower recovery in cardiac pressure change over time (92.5 ± 25.8% vs. 100.5 ± 48.9%; P < 0.05), and a faster return to pre-exercise values in the peripheral vascular resistance (75.2 ± 25.5% vs. 64.8 ± 17.4%; P < 0.001) compared to Sham.ConclusionThe application of IPC after high-intensity exercise promotes the recovery of the cardiovascular system, reducing cardiovascular strain. Future investigations should consider the effects on the sympathetic-parasympathetic balance, such as heart rate variability, to assess further bonds between the use of IPC and autonomous control.

Prediction of early postoperative pain using sleep quality and heart rate variability.

Accurate predictions of postoperative pain intensity are necessary for customizing analgesia plans. Insomnia is a risk factor for severe postoperative pain. Moreover, heart rate variability (HRV) can provide information on the sympathetic-parasympathetic balance in response to noxious stimuli. We developed a prediction model that uses the insomnia severity index (ISI), HRV, and other demographic factors to predict the odds of higher postoperative pain. We recruited gynecological surgery patients classified as American Society of Anesthesiologists class 1-3. An ISI questionnaire was completed 1 day before surgery. HRV was calculated offline using intraoperative electrocardiogram data. Pain severity at the postanesthesia care unit (PACU) was assessed with the 0-10 numerical rating scale (NRS). The primary outcome was the model's predictive ability for moderate-to-severe postoperative pain. The secondary outcome was the relationship between individual risk factors and opioid consumption in the PACU. Our study enrolled 169 women. Higher ISI scores (p = 0.001), higher parasympathetic activity (rMSSD, pNN50, HF; p < 0.001, p < 0.001, p < 0.001), loss of fractal dynamics (SD2, alpha 1; p = 0.012, p = 0.039) in HRV analysis before the end of surgery were associated with higher NRS scores, while laparoscopic surgery (p = 0.031) was associated with lower NRS scores. We constructed a multiple logistic model (area under the curve = 0.852) to predict higher NRS scores at PACU arrival. The five selected predictors were age (OR: 0.94; p = 0.020), ISI score (OR: 1.14; p = 0.002), surgery type (laparoscopic or open; OR: 0.12; p < 0.001), total power (OR: 2.02; p < 0.001), and alpha 1 (OR: 0.03; p < 0.001). We employed a multiple logistic regression model to determine the likelihood of moderate-to-severe postoperative pain upon arrival at the PACU. Physicians could personalize analgesic regimens based on a deeper comprehension of the factors that contribute to postoperative pain.

Cardiovascular autonomic regulation correlates with cognitive performance in patients with a history of traumatic brain injury

Background and objectiveTraumatic brain injury (TBI) may afflict brain areas contributing to both cardiovascular autonomic regulation and cognitive performance. To evaluate possible associations between both functions in patients with a history of TBI (post-TBI-patients), we determined correlations between cardiovascular autonomic regulation and cognitive function in post-TBI-patients.MethodsIn 86 post-TBI-patients (33.1 ± 10.8 years old, 22 women, 36.8 ± 28.9 months after injury), we monitored RR intervals (RRI), systolic and diastolic blood pressures (BPsys, BPdia), and respiration (RESP) at rest. We calculated parameters of total cardiovascular autonomic modulation (RRI-standard-deviation (RRI-SD), RRI-coefficient-of-variation (RRI-CV), RRI-total-powers), sympathetic (RRI-low-frequency-powers (RRI-LF), normalized (nu) RRI-LF-powers, BPsys-LF-powers) and parasympathetic modulation (root-mean-square-of-successive-RRI-differences (RMSSD), RRI-high-frequency-powers (RRI-HF), RRI-HFnu-powers), sympathetic-parasympathetic balance (RRI-LF/HF-ratios), and baroreflex sensitivity (BRS). We used the Mini-Mental State Examination and Clock Drawing Test (CDT) to screen the general global and visuospatial cognitive function, and applied the standardized Trail Making Test (TMT)-A assessing visuospatial abilities and TMT-B assessing executive function. We calculated correlations between autonomic and cognitive parameters (Spearman’s rank correlation test; significance: P < 0.05).ResultsCDT values positively correlated with age (P = 0.013). TMT-A values inversely correlated with RRI-HF-powers (P = 0.033) and BRS (P = 0.043), TMT-B values positively correlated with RRI-LFnu-powers (P = 0.015), RRI-LF/HF-ratios (P = 0.036), and BPsys-LF-powers (P = 0.030), but negatively with RRI-HFnu-powers (P = 0.015).ConclusionsIn patients with a history of TBI, there is an association between decreased visuospatial and executive cognitive performance and reduced parasympathetic cardiac modulation and baroreflex sensitivity with relatively increased sympathetic activity. Altered autonomic control bears an increased cardiovascular risk; cognitive impairment compromises quality of life and living conditions. Thus, both functions should be monitored in post-TBI-patients.

The role of youths' cardiac autonomic balance and parental responses to youth emotion in vulnerability to borderline personality disorder development.

Developmental models of borderline personality disorder (BPD) emphasize the effects of youths' biological vulnerabilities and their experiences of parental responses to emotion, as well as the interaction between these two elements. The current study evaluated the independent and interactive effects of two indices of autonomic nervous system response and parental responses to youth negative emotions on severity and exacerbation of youths' BPD features during the transition to adolescence. The sample consisted of 162 psychiatric youth (10-14 years; 47.2% female) and their parents. At baseline, youth and their parents completed a lab-based conflict discussion during which parasympathetic and sympathetic nervous system response were measured and indices of sympathetic-parasympathetic balance and coactivation/coinhibition were calculated. Youth also reported on supportive and non-supportive parental responses. At baseline and after 9 months, youth self-reported on their BPD features. Results demonstrated that shifting toward sympathetic dominance independently predicted exacerbation of BPD across 9 months. Additionally, fewer experiences of supportive parental responses and more non-supportive parental responses were associated with greater severity of BPD features in youth. This study highlights the role of autonomic response to parent-child conflict as well as the significance of parental responses to youth emotion for the development of BPD during this developmental window.

Immune and neurohumoral profile of the children population living in the conditions of exposure to benzo(a)pyrene

Introduction. Benzo(a)pyrene induces disorders of immune and neurohumoral regulation that are aggravated by the influence of unfavourable climatic and geographical factors in the Far North. In this regard, studies of the features of the immune and neurohumoral profile are of particular relevance for the identification of markers of early health disorders of the population of industrially developed circumpolar territories (using the example of benzo(a)pyrene). Materials and methods. Five hundred 3-6 year children living in the circumpolar territory of Eastern Siberia were examined. Observation group consisted of 352 children living in conditions of exposure to benzo(a)pyrene. Comparison group included 148 children residing at a relatively clean territory. Determination of the content of benzo(a)pyrene in the blood was carried out by HPLC. Phenotyping of CD3+-, CD19+-, CD3+CD95+-, Annexin V-FITC+7AAD- and Annexin V-FITC+7AAD+-lymphocytes was performed by flow cytofluorometry. The level of IgA, IgM, IgG was determined by Mancini radial immunodiffusion, the IgG content to benzo(a)pyrene was determined by allergosorbent testing. The content of acetylcholine, serotonin, and neurotropin-3 was determined by ELISA. Results. Children living in the industrially developed circumpolar territory of Eastern Siberia have an increased level of blood contamination with benzo(a)pyrene (p&lt;0.05). The immune profile is characterized by inhibition of cellular (CD3+ deficiency) and humoral immunity (decreased IgA, IgM, IgG with an excess of CD19+). Violations of apoptosis (decrease in Annexin V-FITC+7AAD-, Annexin V-FITC+7AAD+-lymphocytes; increase in Bcl-2 and CD95+) were revealed (p&lt;0.05). An increased IgG to benz(a)pyrene content were found (p&lt;0.05). The neurohumoral profile of the examined children is characterized by hyperexpression of serotonin with acetylcholine and neurotropin-3 deficiency (p&lt;0.05). Limitations. The results of the study are intended for specialists in the field of hygiene, immunology and allergology. Conclusion. Revealed features of the immune status (deficiency of CD3+, Annexin V-FITC+7AAD-, and Annexin V-FITC+7AAD+-lymphocytes IgA, IgM, IgG, excess CD19+, CD95+, Bcl-2, IgG to benzo(a)pyrene), associated with changes in sympathetic-parasympathetic balance (excess serotonin, deficiency of acetylcholine, neurotropin-3) characterize the features of the immune and neurohumoral profile in the children population of the circumpolar territories of Eastern Siberia under the conditions of exposure to benzo(a)pyrene.

Antiarrhythmic calcium channel blocker verapamil inhibits trek currents in sympathetic neurons.

Background and Purpose: Verapamil, a drug widely used in certain cardiac pathologies, exert its therapeutic effect mainly through the blockade of cardiac L-type calcium channels. However, we also know that both voltage-dependent and certain potassium channels are blocked by verapamil. Because sympathetic neurons of the superior cervical ganglion (SCG) are known to express a good variety of potassium currents, and to finely tune cardiac activity, we speculated that the effect of verapamil on these SCG potassium channels could explain part of the therapeutic action of this drug. To address this question, we decided to study, the effects of verapamil on three different potassium currents observed in SCG neurons: delayed rectifier, A-type and TREK (a subfamily of K2P channels) currents. We also investigated the effect of verapamil on the electrical behavior of sympathetic SCG neurons. Experimental Approach: We employed the Patch-Clamp technique to mouse SCG neurons in culture. Key Results: We found that verapamil depolarizes of the resting membrane potential of SCG neurons. Moreover, we demonstrated that this drug also inhibits A-type potassium currents. Finally, and most importantly, we revealed that the current driven through TREK channels is also inhibited in the presence of verapamil. Conclusion and Implications: We have shown that verapamil causes a clear alteration of excitability in sympathetic nerve cells. This fact undoubtedly leads to an alteration of the sympathetic-parasympathetic balance which may affect cardiac function. Therefore, we propose that these possible peripheral alterations in the autonomic system should be taken into consideration in the prescription of this drug.

Posterior circulation ischemic stroke not involving the brainstem is associated with cardiovascular autonomic dysfunction.

Ischemic stroke may induce cardiovascular autonomic dysfunction, but most previous studies have included patients with anterior circulation ischemic stroke or brainstem stroke. It remains unclear whether posterior circulation ischemic stroke (PCIS) without brainstem involvement also compromises cardiovascular autonomic modulation (CAM). Therefore, we aimed to assess CAM in PCIS patients with and without brainstem involvement. In four subgroups of 61 PCIS patients (14 occipital lobe, 16 thalamic, 12 cerebellar, and 19 brainstem strokes) and 30 healthy controls, we recorded RR intervals (RRIs), systolic (SBP) and diastolic blood pressure (DBP), and respiration at supine rest during the first week after stroke onset. We calculated parameters reflecting total CAM (RRI-standard deviation [RRI-SD], RRI-total powers), predominantly sympathetic CAM (RRI-low-frequency [LF] powers and SBP-LF powers] and parasympathetic CAM (root mean square of successive RRI differences [RMSSD], RRI-high-frequency [HF] powers), sympathetic-parasympathetic balance (RRI-LF/HF ratios), and baroreflex sensitivity (BRS). Values were compared among the four PCIS groups and controls using one-way ANOVA Kruskal-Wallis tests, with post-hoc analyses. Significance was assumed for p &lt; 0.05. In each PCIS subgroup, values for RRI, RRI-SD, RMSSD, RRI-HF powers, and BRS were significantly lower, while SBP-LF powers were higher than in the controls. Only in patients with occipital lobe stroke were RRI-LF/HF ratios significantly higher than in controls. Otherwise, autonomic variables did not differ among the four PCIS subgroups. During the first week after stroke onset, our PCIS patients with occipital lobe, thalamic, cerebellar, or brainstem strokes all had reduced cardiovagal modulation, compromised baroreflex, and increased peripheral sympathetic modulation. The RRI-LF/HF ratios suggest that sympathetic predominance is slightly more prominent after occipital lobe stroke. PCIS may trigger cardiovascular autonomic dysfunction even without brainstem involvement.

ГАМКергические препараты в терапии начальных форм дисциркуляторной энцефалопатии

В настоящее время все большее значение приобретают функциональные расстройства при цереброваскулярных заболеваниях: тревога, ларвированная депрессия, когнитивные нарушения, инсомния и др. Это и нейрокардиальная проблема, и психосоматическая патология, требующая пересмотра существующих рутинных схем фармакотерапии, более многовекторного патогенетического подхода к лечению. В статье приведены результаты открытого пилотного когортного проспективного клинического исследования среди пациентов с дисциркуляторной энцефалопатией 1–2-й стадии. У пациентов с цереброваскулярной патологией применяли препарат Гамалате В6, нормализующий психоэмоциональные и мнестические функции — краткосрочную и долговременную память, снижающий уровень личностной и ситуативной тревожности. Под влиянием курсового приема Гамалате В6 улучшается мозговое крово­обращение: увеличивается скорость кровотока и снижается периферическое сопротивление в экстракраниальных сосудах каротидного бассейна. Гамалате В6 гармонизирует активность таламокортикальных структур (увеличивает мощность альфа-ритма на фоне снижения ЭЭГ-мощности подкорковых структур, генерирующих медленные ритмы) и симпатико-парасимпатический баланс вегетативной нервной системы по оценкам вариабельности ритма сердца.

Plethysmographic Peripheral Perfusion Index: Could It Be a New Vital Sign?

The plethysmographic peripheral perfusion index (PPI) is a very useful parameter with various emerging utilities in medical practice. The PPI represents the ratio between pulsatile and non-pulsatile portions in peripheral circulation and is mainly affected by two main determinants: cardiac output and balance between sympathetic and parasympathetic nervous systems. The PPI decreases in cases of sympathetic predominance and/or low cardiac output states; therefore, it is a useful predictor of patient outcomes in critical care units. The PPI could be a surrogate for cardiac output in tests for fluid responsiveness, as an objective measure of pain especially in un-cooperative patients, and as a predictor of successful weaning from mechanical ventilation. The PPI is simple to measure, easy to interpret, and has continuously displayed variables, making it a convenient parameter for detecting the adequacy of blood flow and sympathetic-parasympathetic balance.

Salusin-β in Intermediate Dorsal Motor Nucleus of the Vagus Regulates Sympathetic-Parasympathetic Balance and Blood Pressure.

The dorsal motor nucleus of the vagus (DMV) is known to control vagal activity. It is unknown whether the DMV regulates sympathetic activity and whether salusin-β in the DMV contributes to autonomic nervous activity. We investigated the roles of salusin-β in DMV in regulating sympathetic-parasympathetic balance and its underline mechanisms. Microinjections were carried out in the DMV and hypothalamic paraventricular nucleus (PVN) in male adult anesthetized rats. Renal sympathetic nerve activity (RSNA), blood pressure and heart rate were recorded. Immunohistochemistry for salusin-β and reactive oxidative species (ROS) production in the DMV were examined. Salusin-β was expressed in the intermediate DMV (iDMV). Salusin-β in the iDMV not only inhibited RSNA but also enhanced vagal activity and thereby reduced blood pressure and heart rate. The roles of salusin-β in causing vagal activation were mediated by NAD(P)H oxidase-dependent superoxide anion production in the iDMV. The roles of salusin-β in inhibiting RSNA were mediated by not only the NAD(P)H oxidase-originated superoxide anion production in the iDMV but also the γ-aminobutyric acid (GABA)A receptor activation in PVN. Moreover, endogenous salusin-β and ROS production in the iDMV play a tonic role in inhibiting RSNA. These results indicate that salusin-β in the iDMV inhibits sympathetic activity and enhances vagal activity, and thereby reduces blood pressure and heart rate, which are mediated by NAD(P)H oxidase-dependent ROS production in the iDMV. Moreover, GABAA receptor in the PVN mediates the effect of salusin-β on sympathetic inhibition. Endogenous salusin-β and ROS production in the iDMV play a tonic role in inhibiting sympathetic activity.

Abstract P054: Duration Of Diabetes, Glucose Excursions, Glycemic Control, And Low Heart Rate Variability: The Atherosclerosis Risk In Communities (aric) Study

Introduction: Individuals with diabetes often have low heart rate variability (HRV)—a marker of autonomic dysfunction. How diabetes duration, glucose excursions, and poor glycemic control relate to HRV is not well characterized. Objectives: To evaluate the associations of diabetes status, duration of diabetes, and biomarkers of glucose excursions (1,5-anhydroglucitol [1,5-AG]—a measure of glycosuria) and glycemic control with HRV. Methods: We conducted a cross-sectional analysis of ARIC Study participants who underwent a 2-minute electrocardiogram at visit 4 (1996-98). We considered root mean square of successive differences in normal-to-normal R-R intervals (rMSSD, measure of parasympathetic activity), standard deviation of normal-to-normal R-R intervals (SDNN, total variability), low frequency (LF, primarily sympathetic activity), high frequency (HF, reflects parasympathetic activity), and LF/HF ratio (sympathetic-parasympathetic balance) as HRV indices. In persons with diabetes, we compared geometric means of HRV indices by diabetes duration (&lt;5 years vs ≥5 years), 1,5-AG (&lt;6 μg/mL vs ≥6 μg/mL), and glucose control (estimated A1C &lt;8% vs ≥8%). We obtained p-values from linear regressions adjusted for age and sex. Results: Among 10169 participants (mean age 63, 57% female, 22% black), participants with diabetes had significantly lower rMSSD, SDNN, LF, HF, and LF/HF ratio compared to those without diabetes ( Table ). Among the 1667 participants with diabetes, longer duration of diabetes, low 1,5-AG, and poor glycemic control were associated with lower rMSSD, SDNN, LF, and HF. No statistically significant associations were found for diabetes duration, 1,5-AG, glycemic control with LF/HF ratio. Discussion: Our results demonstrate that longer duration of diabetes, glucose excursions, and poor glycemic control are associated with some measures of low HRV. This study underscores that cardiac autonomic neuropathy is a common but overlooked complication of long-standing and/or poorly managed diabetes.

Effects of oral function on pupil response: a new view on bruxism pathophysiology.

There is increasing evidence of the influence of the oropharyngeal stimulations on the autonomic nervous system and an easy approach to evaluate the balance between parasympathetic and sympathetic system is the measurement of the pupil diameter. The aim of this analytic observational study is to define the effects of clenching and swallowing on pupil diameter, and how an oral appliance can affect the outcome of these tasks, to establish their influence on the sympathetic-parasympathetic balance. We measured the pupil diameter in 30 healthy subjects during clenching and swallowing, both with and without oral appliance. We compared the results with the mandibular rest position. The respective positions with and without oral appliance were also compared. Pupillometry showed a mydriatic effect of swallowing (rest 6.94 mm, swallowing 7.26 mm, P=0.04) and oral appliance, more relevant in scotopic conditions. On the contrary, clenching seemed to enhance miosis, especially in intense brightness condition (rest 3.95 mm, clenching 3.83 mm, P=0.02). Swallowing and oral appliance facilitate the sympathetic system, while clenching activates the parasympathetic branch. We argue that probably the locus coeruleus is the main hub. These results could have practical implications in bruxism physiology, because it could be an attempt to counteract the activation of the sympathetic system.

Psychophysical training in treatment of sympathicotonic vegetative dystonia syndrome and primary arterial hypertension in children and adolescents

Objective. To evaluate the effectiveness of psychophysical training as a method of non-drug correction of vegetative dystonia syndrome of sympaticotonic type and primary arterial hypertension in children and adolescents.&#x0D; Material and methods. 164 patients aged 717 years with sympathicotonic vegetative dystonia syndrome were examined, of which 47 were diagnosed primary arterial hypertension. The baseline autonomic tone (by cumulative clinical tables of autonomic manifestations), autonomic reactivity (based on the results of variation pulsography in ortho-and clean position), support activities (by clean orthostatic test) were evaluated, the heart rate variability was analyzed. As a method of non-drug correction of the functional state of the autonomic nervous system, psychophysical training (main group, n = 110) and therapeutic physical culture (comparison group, n = 54) were used. To assess the effectiveness of treatment, patients were examined twice: before and after the course.&#x0D; Results. It was found that in the sympaticotonic type of vegetative system, excessive vegetative reactivity and activity maintenance predominate. The use of psychophysical training leads to their normalization in most patients. In patients with primary arterial hypertension, the level of blood pressure decreases. According to the analysis of heart rate variability in the main group there is a significant increase in the total power spectrum of neurohumoral regulation, representation of high-frequency fluctuations with simultaneous reduction of the share of low-frequency waves as well as aligned sympathetic-parasympathetic balance.&#x0D; Conclusion. Psychophysical training is an effective method for non-drug correction of vegetative dystonia syndrome by sympaticotonic type and primary arterial hypertension in children and adolescents.

The effects of six-week slow, controlled breathing exercises on heart rate variability in physically active, healthy individuals

Background and Study Aim: Heart rate variability (HRV) provides information about sympathetic-parasympathetic balance. The effects of different types of physical exercises on HRV have been investigated so far. The purpose of the current study was to evaluate the chronic effects of six-week slow and controlled breathing exercise on HRV in physically active, healthy adults.&#x0D; Material and Methods: A total of 22 individuals (11 female, 11 male) participated in the study voluntarily. The experimental group (EG) attended to the breathing exercises for 15 minutes per day, three days a week for six weeks. Neither the EG nor the control group (CG) did join in any regular physical activity program during the study. Both groups participated in the HRV measurements before and after the six-week of process.&#x0D; Results: Only the EG showed statistically significant changes in some HRV parameters. The alterations observed in LF:HF ratio, HFnu, and LFnu parameters were to reflect the increase in parasympathetic activity. Although the changes in the other parameters of HRV such as SDNN, SDSD, RMSSD, TP, HF, LF, and VLF were also related to increased vagal activity, these alterations were not significant. However, no significant change was found in the CG.&#x0D; Conclusions: These results show that only the slow, controlled breathing exercises for six weeks could be used to improve parasympathetic activity in physically active individuals. A study could be designed where the duration is kept over 8 weeks, and the effects of physical exercises only, breathing exercises only, and physical + breathing exercises together on HRV are examined.

The effects of six-week slow, controlled breathing exercises on heart rate variability in physically active, healthy individuals

Background and Study Aim: Heart rate variability (HRV) provides information about sympathetic-parasympathetic balance. The effects of different types of physical exercises on HRV have been investigated so far. The purpose of the current study was to evaluate the chronic effects of six-week slow and controlled breathing exercise on HRV in physically active, healthy adults.&#x0D; Material and Methods: A total of 22 individuals (11 female, 11 male) participated in the study voluntarily. The experimental group (EG) attended to the breathing exercises for 15 minutes per day, three days a week for six weeks. Neither the EG nor the control group (CG) did join in any regular physical activity program during the study. Both groups participated in the HRV measurements before and after the six-week of process.&#x0D; Results: Only the EG showed statistically significant changes in some HRV parameters. The alterations observed in LF:HF ratio, HFnu, and LFnu parameters were to reflect the increase in parasympathetic activity. Although the changes in the other parameters of HRV such as SDNN, SDSD, RMSSD, TP, HF, LF, and VLF were also related to increased vagal activity, these alterations were not significant. However, no significant change was found in the CG.&#x0D; Conclusions: These results show that only the slow, controlled breathing exercises for six weeks could be used to improve parasympathetic activity in physically active individuals. A study could be designed where the duration is kept over 8 weeks, and the effects of physical exercises only, breathing exercises only, and physical + breathing exercises together on HRV are examined.

Resistance of postprandial gastric functions and autonomic balance to taste stimulation.

Exposure to unpleasant tastes leads to disturbances of interdigestive gastric myoelectrical activity (GMA) and may affect sympathetic/parasympathetic balance (SPB). We made a careful study to determine whether taste stimulation modulates the postprandial GMA, SPB, and gastric emptying (GE) of a solid meal. Eighteen healthy volunteers (9F/9M) entered the study. On six separate days, we recorded a four-channel electrogastrogram from each volunteer during a 35-min fasting period, then for 90 min after ingestion of a solid test meal of 300 kcal. GE was measured using a 13C-octanoic acid breath test. Heart rate variability (HRV) analysis was simultaneously performed. At the start of the 21st min after the test meal, subjects received an agar cube delivering either a sweet, salty, sour, or bitter taste, which they kept in the mouth for 35 min. Control procedures involved sessions performed with a tasteless agar cube, and without any stimulation. There was no effect of the experimental intervention upon the relative power share of particular GMA rhythms. Stimulation with the salty and the bitter taste evoked a statistically significant increase in the dominant frequency, whereas the sweet and sour taste did not affect it. Taste stimulation did not interfere with the meal-induced rise in the dominant power, nor affect slow wave coupling. The kinetics of the solid GE remained unchanged by the intervention. None of the taste stimulations affected the postprandial SPB. Taste stimulation elicited after ingestion of a meal, in contrast to that during a fast, did not adversely modify the postprandial pattern of either the GMA or SPB, nor affect the GE of solids.

Personalization of Nordic walking programs in a sanatorium-type medical center

To assess the effectiveness of Nordic walking in adolescent 15-17 years old depending on type of initial vegetative tone and the time of the lessons. It was examined 60 adolescents aged 15-17 years of the II health group including 30 persons with vagotonic and 30 persons with sympathicotonic type of initial vegetative tone. In each groups the subgroups were identified who were engaged in Nordic walking from 8:00 to 9:00 (morning subgroups, 15 teenagers) and from 18:00 to 19:00 (evening subgroups, 15 teenagers). The course included 21 sessions of 45 minutes daily. Heart rate variability, the level of self-esteem according to D. Keirsey, well-being, activity and mood according to the SAN method, subjective load tolerance according to the Borg scale and general physical endurance according to the results of a test with a 6-minute run were assessed. A significant positive effect was observed with the differentiated use of Nordic walking taking into account the type of the initial vegetative tone and the daily rhythm of physical activity. In adolescent vagotonics training in the evening according to the analysis of heart rate variability, the functional reserve and activity of regulatory systems increased with a tendency to normalize the sympathetic-parasympathetic balance, the indicators of the psychological sphere improved, physical endurance increased, as well as the motivation for training and their subjective tolerance. In sympathicotonic adolescents, a similar positive effect of Nordic walking took place when exercising in the morning. A different distribution of training time (morning hours for vagotonics and evening hours for sympathicotonics) was accompanied by tension in the work of the autonomic nervous system apparatus caused disharmony in the emotional state, did not lead to an increase in physical endurance and worsened subjective load tolerance. When planning a course of Nordic walking in adolescents it is necessary to take into account the type of initial vegetative tone and choose the right time for classes: with vagotonia they should be carried out in the evening, with sympathicotonia - in the morning.