Autonomic Nervous System Balance Research Articles

Psychophysiological profile of ischemic patients according to their resting heart rate variability: one step closer to training individualization

Ischemic heart disease continues to be a major cause of morbidity and mortality around the world. Nowadays, research is focusing on the role of the brain-heart axis in autonomic nervous system balance. Resting heart rate variability (HRV) could help to identify the readiness of ischemic patients to achieve cardiac rehabilitation exercise stimulus in a safer manner. The objectives of the study were i) to analyze the resting HRV in ischemic cardiopathy, determining whether it was below or within its normal range, and ii) to identify the effect of the psychophysiological parameters of age, body mass index (BMI), blood pressure, cardiorespiratory fitness, and quality of life. This was a cross-sectional study of patients affected by ischemic cardiopathy. The patients were divided into the nonNormal-HRV or Normal-HRV group according to their normal resting HRV. The HRV temporal and frequency domains were recorded along with heart rate and blood pressure, BMI, cardiorespiratory fitness and auto-perception. The sample comprised men with an average age of 58.64±9.54 years. In total, 43.92% were below their normal resting-HRV range. They were older (P<.001, d=.856), had worse auto-perception (P<.001, d=.473), and higher systolic and lower diastolic blood pressure (P<.001, d=.446; P=.007, d=.29). HRV domains correlated directly (P<.05) with diastolic blood pressure and inversely with heart rate and age. The percentage of low resting-HRV scores in ischemic patients was higher than expected and was conditioned by age, blood pressure and heart rate. Moreover, the patients had worse auto-perception. All these factors should be considered to optimize cardiac rehabilitation programs.

Feet-heating and Calf-heating have Opposing Effects on Glucose Tolerance and Heart Rate Variability: A Randomized, Controlled, Crossover Trial.

Heat exposure's effect on glucose tolerance depending on the amount of body exposure, likely relating to autonomic nervous system balance. We assessed how partial-body heat exposure at two different levels of the lower extremities would affect glucose tolerance and autonomic nervous system balance measured via heart rate variability. We hypothesized feet-heating would improve glucose tolerance without affecting heart rate variability while calf-heating would worsen glucose tolerance and decrease heart rate variability compared to a thermoneutral control condition. In a randomized, controlled, crossover trial, healthy participants' (N=31, 23(3)years, 45% male) glucose tolerance was measured in A)thermoneutral; B)feet-heating; and C)calf-heating conditions. Every 30 minutes for 2 hours, blood glucose, heart rate, heart rate variability, tympanic temperature, thermal comfort scores, and blood pressure were measured. There were significant interactions between condition and time for blood glucose (F(4.6,72.6)=2.6,p=.036), heart rate (F(3.4,54.5)=3.5,p=.017), heart rate variability (F(4.3,63.2)=7.5,p<.0001), tympanic temperature (F(8,268)=2.4,p=.014), and thermal comfort scores (F(8,248)=22.1,p<.0001). Calf-heating increased 90-minute glucose (+12(95%CI: 3 to 21)mg/dL,p=.013) and decreased heart rate variability throughout (mean decrease: 13-22%,p<.007), while feet-heating lowered 90-minute glucose (-7(95%CI:-16 to +1)mg/dL,p=.090) without affecting heart rate variability (p=.14-.99). Blood pressure and body temperature were similar between conditions, but heart rate and thermal comfort scores increased with heating. Calf-heating worsens, while feet-heating may improve, glucose tolerance. Changes in heart rate variability coincide with changes in glucose tolerance despite unchanged body temperature. Whether heart rate variability can be used to monitor autonomic nervous system balance during heating to the effect on acute glycemic indices should be further explored.

Stellate Ganglion Block may represent an effective therapeutic for Primary Sjögren’s Syndrome

Primary Sjogren’s syndrome (pSS) is a systemic autoimmune inflammatory disease characterized by xerophthalmia and xerostomia,leading to a notable decline in patients’ quality of life. Recent studies have shown a link between the autonomic nervous system (ANS) dysfunction and pSS. The salivary and lacrimal glands are innervated by both sympathetic and parasympathetic nerves, highlighting the role of the ANS. Stellate ganglion block (SGB), a commonly used nerve block technique in clinical settings, exhibits the ability to modulate both the ANS and the immune response. Therefore, our hypothesis suggests that SGB may alleviate xerostomia and xerophthalmia in pSS patients through a short-term mechanism involving the adjustment of ANS balance and vasodilation to facilitate glandular secretion. Additionally, the long-term efficacy of SGB in pSS may be attributed to its neuroimmunomodulatory effects. Furthermore,it is likely that SGB could also improve a variety of ANS-related extra-glandular symptoms in pSS, including digestive, cardiovascular, neurological, and psychological issues.

Role and mechanism of autonomic nervous system regulation in primary glaucoma

The regulation of blood flow in the human eye, aqueous humor production, and the outflow channels of aqueous humor are all controlled by the autonomic nervous system (ANS), encompassing both sympathetic and parasympathetic nerves. Patients with primary glaucoma often exhibit autonomic nervous system dysfunctions, which may exacerbate visual impairment. The homeostasis of the autonomic nervous system is influenced by circadian rhythms, physical exercise, emotional states, medications, and other factors. Previous studies have indicated that activities such as aerobic exercise, yoga breathing, and meditation can promote the restoration of autonomic nervous system balance, thereby reducing intraocular pressure. However, further evidence is required to substantiate the efficacy of ANS activity regulation as an effective adjunct therapy for primary glaucoma. This review examines the role and mechanisms of autonomic nervous system regulation in the context of primary glaucoma.

Effects of Virtual Reality (VR)-Based Meditation on Sleep Quality, Stress, and Autonomic Nervous System Balance in Nursing Students.

This study aimed to determine the effects of virtual reality (VR)-based meditation on the sleep quality, stress, and autonomic nervous system balance of nursing students. Nursing students were categorized into experimental groups I (VR-based meditation) and II (concentration meditation) and a control group. Before the study's initiation, we measured the participants' general characteristics, and a sleep measurement device was used to measure sleep quality. Stress levels and heart rate variability were measured before and after study completion. On the first day, all three groups slept without any intervention. On days 2-6, only experimental groups I and II implemented the intervention before sleeping. We found that the subjective sleep quality, wakefulness after sleep onset, sleep efficiency, deep sleep quality, subjective stress, objective stress, and autonomic nervous system balance of the VR meditation group were significantly better than those of the other groups. Our results reveal that the participants who underwent VR-based meditation experienced better sleep quality, lower stress levels, and improved autonomic nervous system balance compared with those in the concentration meditation and control groups. Thus, VR-based meditation effectively enhances sleep quality, lowers stress levels, and improves autonomic nervous system balance in nursing students.

안마의자를 활용하는 마사지가 성인 남녀의 자율신경균형도에 미치는 즉각적 영향: 전향적 관찰연구

Objectives The aim of this study was to examine the immediate impact of a massage chair intervention on homeostasis and the balance of the autonomic nervous system in individuals aged 20 to 64. Methods This study was a single-center, prospective, single-arm, investigator-initiated observational study. Non-underweight adults without significant health concerns underwent a 40-minute massage chair intervention. Measurements of heart rate variability, functional near-infrared spectroscopy, and vital signs were conducted before and after the intervention. Additionally, participants completed the Mibyeong questionnaire and a satisfaction survey. Results A 40-minute massage chair session led to a notable decrease in average heart rate and low frequency to high frequency (LF/HF) ratio, coupled with an increase in root mean square of the successive differences (RMSSD) and standard deviation of NN interval (SDNN). No adverse reactions were noted. Subjects with elevated sympathetic nerve activity exhibited a reduction in LF/HF ratio, whereas those with heightened parasympathetic activity demonstrated an increase in LF/HF ratio post-intervention. Conclusions The findings indicate that the massage chair intervention has the potential to activate the parasympathetic nervous system, promote blood pressure homeostasis and autonomic nervous system balance. However, further research over a more extended period is crucial to validate these conclusions.

Trends and Prospects for Photoreactivation in Health Promotion

The use of light to promote health, reduce harm, and restore functionality is a novel, non-accumulative physical strategy that contrasts with the predominantly chemical approaches used in Western medicine. This strategy may serve as an independent function for healthcare professionals and warrants further exploration. Photoreactivation, achieved by adjusting patients' physiological clocks at different times, utilizing specific wavelengths, varying color temperatures, and using illuminance, is a potent tool for improving mood and sleep quality, regulating autonomic nervous system balance, enhancing attention, and delaying cognitive decline. Light therapy is a rapidly expanding field in healthcare that offers new opportunities to enhance quality of life, prevent diseases, and improve overall well-being. This article elucidates the fundamental concepts of photoreactivation, explores its application across diverse health domains, examines its future development prospects, and discusses the challenges faced by photoreactivation and related solutions to ensure the responsible use of light to enhance and restore physiological and psychological functions.

Predict Sarcopenia Risk in the Elderly by Cardiovascular Function and Heart Rate Variability

Objectives: Preventing and slowing sarcopenia in older people has become an important health issue. Heart rate variability reflects autonomic nervous system balance, and along with cardiovascular function, can indicate potential sarcopenia risk by signaling disruptions in muscle-supporting blood flow and autonomic control. Our objective was to collect simple and non-invasive cardiovascular function measurements and heart rate variability parameters to develop a model for predicting sarcopenia risk. Methods: We conducted a 3-minute cardiovascular function and heart rate variability test and sarcopenia screening (appendicular skeletal muscle index, grip strength, and walking speed) on 418 participants (105 males, 313 females, mean age 73.32±8.81 years) recruited from central Taiwan. Results: Appendicular skeletal muscle index, grip strength, walking speed, cardiovascular function, and heart rate variability had a significant correlation. The key features for predicting sarcopenia risk with logistic regression analysis were age, reflection index, dicrotic elasticity index, and high-frequency power (the overall accuracy was 70.10%; sensitivity was 81.30%; specificity was 54.07%). Conclusions: Simple and non-invasive 3-minute cardiovascular function and heart rate variability test parameters significantly predict sarcopenia risk in older people. This model can be applied to technology devices to detect sarcopenia risk and prevent sarcopenia in older people.

Multimodal coupling and HRV assessment characterize autonomic functional changes in congestive heart failure patients with sinus rhythm or severe arrhythmia

Autonomic nervous system (ANS) dysfunction is a significant characteristic of patients with congestive heart failure (CHF). Respiratory sinus arrhythmia (RSA) serves as an index of parasympathetic nervous system (PNS) function usually quantified by the high-frequency power of heart rate variability (HRV). However, the high breathing rate of CHF patients results in deviations when estimating RSA by HRV. Multimodal coupling analysis (MMCA) is a novel method of quantifying RSA which decomposes the R-R signal adaptively into intrinsic mode functions (IMFs) followed by identification of the RSA-related IMF. MMCA also calculates the phase synchronization between RSA-related IMF and respiratory signals to exclude the influences that are unrelated to RSA. In this study, we introduced HRV and MMCA-derived parameters to quantify ANS function for CHF patients, along with their comparisons in the clinical efficacy evaluation. Thirty-seven CHF patients were recruited, including 17 with sinus rhythm (SRHF) and 20 with severe arrhythmia (ARHF). Our results showed that all parameters for SRHF patients increased after treatment except for LF/HF. Only LF/HF, α2, and MMCA-derived RSA showed significant differences after treatment for ARHF patients, wherein the MMCA-derived RSA significantly decreased regardless of the left ventricular ejection fraction. The PNS function and ANS balance were recovered in all the CHF patients after treatment. Metrics including MeanRR, SDRR, LF, HF, TPower, SD1, SD2, and MMCA-derived RSA showed more significant improvements in SRHF patients whose New York Heart Association functional class improved after treatment. These metrics can be used to guide prognosis and therapeutic efficacy monitoring.

Pressure Building Against the Clock: The Impact of Circadian Misalignment on Blood Pressure.

Misalignment between the endogenous biological timing system and behavioral activities (i.e., sleep/wake, eating, activity) contributes to adverse cardiovascular health. In this review, we discuss the effects of recurring circadian misalignment on blood pressure regulation and the implications for hypertension development. Additionally, we highlight emerging therapeutic approaches designed to mitigate the negative cardiovascular consequences elicited by circadian disruption. Circadian misalignment elicited by work schedules that require individuals to be awake during the biological night (i.e., shift work) alters 24-h blood pressure rhythms. Mechanistically, circadian misalignment appears to alter blood pressure via changes in autonomic nervous system balance, variations to sodium retention, dysregulation of endothelial vasodilatory responsiveness, and activation of proinflammatory mechanisms. Recurring circadian misalignment produced by a mismatch in sleep timing on free days vs. work days (i.e., social jetlag) appears to have no direct effects on prevailing blood pressure levels in healthy adults; though, circadian disruptions resulting from social jetlag may increase the risk of hypertension through enhanced sympathetic activation and/or obesity. Furthermore, social jetlag assessment may be a useful metric in shift work populations where the magnitude of circadian misalignment may be greater than in the general population. Circadian misalignment promotes unfavorable changes to 24-h blood pressure rhythms, most notably in shift working populations. While light therapy, melatonin supplementation, and the timing of drug administration may improve cardiovascular outcomes, interventions designed to target the effects of circadian misalignment on blood pressure regulation are warranted.

Tai Chi Effects on Heart Rate Variability: A Systematic Review and Meta-Analysis.

Background: Tai Chi, originating in China, is a mind-body exercise that integrates mind training, Qi training, and body training. While Tai Chi practice has demonstrated beneficial physical and psychological health benefits, how it achieves effects has been less studied. In recent years, some researchers have begun to explore the potential of heart rate variability (HRV) changes as balancing the autonomic nervous system (ANS) to achieve results, but only a few studies have directly tested how Tai Chi impacts HRV, and results have been mixed. Objective: This study systematically evaluates the effects of Tai Chi on HRV. Methods: Electronic databases including Web of Science, PubMed, Scopus, Cochrane Library, and EBSCOhost direct from inception until December 2020 were searched to obtain eligible studies. The primary outcomes examined were HRV parameters (time domain and frequency domain), and secondary analysis was whether breathing was emphasized during Tai Chi interventions. Results: Based on the 11 randomized controlled trials included comparing Tai Chi with non-active control condition, meta-analyses showed significantly beneficial effects on HRV parameters (low-frequency power [LF], mean difference [MD] = -200.40, 95% confidence interval [CI]: 365.31 to -35.49, p = 0.02; normalized low-frequency power [nLF], MD = -7.39, 95% CI: -12.48 to -2.29, p = 0.004; total power [TP], MD = -649.82, 95% CI: -1180.54 to -119.11, p = 0.02; very low-frequency power [VLF], MD = -200.55, 95% CI: -349.63 to -51.46, p = 0.008; root mean square of the square sum of the difference between adjacent normal heartbeat intervals [RMSSD], MD = 2.59, 95% CI: -7.23 to 12.41, p < 0.0001; standard deviation of the heartbeat interval [SDNN], MD = 8.33, 95% CI: 0.69 to 15.98, p = 0.03). The effect of Tai Chi on certain HRV parameters compared with active control conditions was less favorable (nLF, MD = 6.42, 95% CI: 3.74 to 9.09, p < 0.00001; normalized high-frequency power [nHF], MD: -6.13, 95% CI: -8.76 to -3.50, p < 0.00001; low-frequency/high-frequency power ratio [LF/HF], MD = 1.00, 95% CI: 0.68 to 1.33, p < 0.00001). In addition, studies describing an emphasis on breathing in the Tai Chi intervention showed positive impact on HRV (nLF, MD = -3.22, 95% CI: -5.32 to -1.12, p = 0.003; nHF, MD = 3.80, 95% CI: 0.80 to 6.81, p = 0.01; SDNN, MD = 5.55, 95% CI: 4.85 to 6.25, p < 0.00001). Conclusions: Meta-analysis results showed that Tai Chi compared with non-active control conditions has a positive impact on key HRV parameters associated with the ANS balance. However, active control condition comparisons showed greater HRV improvements than for Tai Chi. Considering the limited number of studies and their heterogeneity, further robust studies are necessary to verify findings and investigate differential effects of Tai Chi on HRV.

Effect of Head-Up/-Down Tilt on ECG Segments and Myocardial Temporal Dispersion in Healthy Subjects.

The head-up/-down tilt test acutely modifies the autonomic nervous system balance throughout a deactivation of the cardiopulmonary reflexes. The present study examines the influence of head-up/-down tilt on a number of ECG segments. A total of 20 healthy subjects underwent a 5 min ECG and noninvasive hemodynamic bio-impedance recording, during free and controlled breathing, lying at (a) 0°; (b) -45°, tilting up at 45°, and tilting up at 90°. Heart rate variability power spectral analysis was obtained throughout some ECG intervals: P-P (P), P-Q (PQ), PeQ (from the end of P to Q wave), Q-R peak (QR intervals), Q-R-S (QRS), Q-T peak (QTp), Q-T end (QTe), STp, STe, T peak-T end (Te), and, eventually, the TeP segments (from the end of T to the next P waves). Results: In all study conditions, the Low Frequency/High FrequencyPP and LFPP normalized units (nu) were significantly lower than the LF/HFRR and LFRRnu, respectively. Conversely, the HFPP and HFPPnu were significantly higher in all study conditions. STe, QTp, and QTe were significantly related to the PP and RR intervals, whereas the T wave amplitude was inversely related to the standard deviations of all the myocardial repolarization variables and to the left ventricular end-systolic volume (LVEDV). The T wave amplitude diminished during head-up tilt and significantly correlated with the LVEDV.

ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature.

Some patients remain unwell for months after "recovering" from acute COVID-19. They develop persistent fatigue, cognitive problems, headaches, disrupted sleep, myalgias and arthralgias, post-exertional malaise, orthostatic intolerance and other symptoms that greatly interfere with their ability to function and that can leave some people housebound and disabled. The illness (Long COVID) is similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as well as to persisting illnesses that can follow a wide variety of other infectious agents and following major traumatic injury. Together, these illnesses are projected to cost the U.S. trillions of dollars. In this review, we first compare the symptoms of ME/CFS and Long COVID, noting the considerable similarities and the few differences. We then compare in extensive detail the underlying pathophysiology of these two conditions, focusing on abnormalities of the central and autonomic nervous system, lungs, heart, vasculature, immune system, gut microbiome, energy metabolism and redox balance. This comparison highlights how strong the evidence is for each abnormality, in each illness, and helps to set priorities for future investigation. The review provides a current road map to the extensive literature on the underlying biology of both illnesses.

Autonomic nervous system balance in parturient mares: Spontaneous vs induced delivery.

Delivery is not easily predictable in horses and the consequences of dystocia can be serious for both the mare and foal. An induction protocol with low doses of oxytocin has been reported as a safe procedure. This study investigates the effect of induced delivery on at-term mares' sympathetic-vagal balance. Fourteen mares were included and divided into two groups, one subjected to spontaneous delivery (SD), and one to induced delivery (ID). In both groups, an ECG was recorded using an elastic belt with integrated smart textile electrodes. The recording started before the delivery (Basal), continued close to delivery (Pre-delivery) and during delivery (Delivery), and ended after parturition (Placental expulsion). From the ECGs, Heart Rate Variability (HRV) parameters relating to time and frequency domains and non-linear analysis were extrapolated. The HRV analysis was performed both within the same group (IntraGA) and between the two groups (InterGA). In the present study, spontaneous and induced delivery did not appear to differ in autonomic nervous system functioning. In IntraGA analysis, both for SD and ID mares, delivery and placental expulsion periods were parasympathetic dominated since vagal-related HRV parameters increased. Moreover, no differences were found in InterGA comparison between SD and ID mares, except for the pre-delivery period of ID mares, during which both branches of the autonomic nervous system were activated. These results are in line with the literature on parasympathetic dominance during parturition and no change in Heart Rate Variability following exogenous oxytocin administration in parturient mares.

Nocturnal Heart Rate Variability in Women Discordant for Hormonal Contraceptive Use.

The aim of this study was to investigate within-cycle differences in nocturnal heart rate (HR) and heart rate variability (HRV) in naturally menstruating women (NM) and women using combined hormonal contraceptives (CU) or progestin-only hormonal contraceptives (PU). Physically active participants were recruited into three groups: NM ( n = 19), CU ( n = 11), and PU ( n = 12). Participants' HR and HRV (with Bodyguard 2 HRV monitor) and blood hormones were monitored during one menstrual cycle (MC) (NM group) or for 4 wk (CU and PU groups). Estradiol, progesterone, and luteinizing hormone were analyzed from fasting blood samples collected four times in the NM (M1 = bleeding, M2 = follicular phase, M3 = ovulation, and M4 = luteal phase) and PU groups (M1 = lowest E 2 , M2 = M1 + 7 d, M3 = M1 + 14 d, and M4 = M1 + 21 d) and twice in the CU group (active and inactive pill phases). After every blood sample, nightly HR and HRV were recorded and examined as an average from two nights. Hormonal concentrations differed ( P < 0.05) between MC phases in the NM and PU groups, but not ( P ≥ 0.116) between the active and the inactive phases in the CU group. In the NM and PU groups, some of the HRV values were higher, whereas in the NM group, HR was lower during M2 compared with M3 ( P < 0.049) and M4 ( P < 0.035). In the CU group, HRV values ( P = 0.014-0.038) were higher, and HR was lower ( P = 0.038) in the inactive phase compared with the first week of the active phase. The MC and the hormonal cycle phases influence autonomic nervous system balance, which is reflected in measurements of nocturnal HR and HRV. This should be considered when monitoring recovery in physically active individuals.

Effects of Transcutaneous Trigeminal Electrical Stimulation and Sound Therapy in Patients with Tinnitus.

Tinnitus is one of the most common health conditions worldwide. Although various methods of treatment have been used, the condition is still difficult to manage or cure. This study aimed to evaluate the therapeutic effects of transcutaneous trigeminal electrical stimulation (TTES) combined with notched sound therapy (NST) on patients with tinnitus. A clinical trial was conducted prospectively from September 2020 to September 2021 at a single center in South Korea. In total, 14 patients took part in this trial. Periodic visits and tele-monitoring were used to assess treatment compliance and collect data, including electroencephalography (EEG), photoplethysmography (PPG), tinnitus handicap inventory (THI), tinnitus magnitude index, Beck Depression Inventory (BDI), Pittsburgh Sleep Quality Index (PSQI), and 36-item short-form survey (SF-36) results. Changes after intervention were analyzed with paired t-test. This study showed that alpha waves in the left hemisphere measured by EEG (p=0.024), autonomic nervous system balance (p=0.007), and stress level (p=0.022) measured by PPG significantly changed after intervention. Also, THI scores especially emotional symptoms (p=0.029) and catastrophic symptoms (p=0.043) decreased after treatment. The SF-36 score, both mental component summary and physical component summary score (each p<0.001), increased significantly, whereas the PSQI score (p<0.001) and BDI score (p<0.001) decreased after TTES and NST. Based on the results of our study, we could confirm that TTES combined with NST can significantly improve tinnitus, catastrophic symptoms, and the overall quality of life of patients.

PS-B10-5: EFFECTS OF CHRONIC ACETYLCHOLINESTERASE INHIBITION WITH PYRIDOSTIGMINE ON CARDIOVASCULAR SYSTEM AND AUTONOMIC BALANCE IN SPONTANEOUSLY HYPERTENSIVE RATS

Objective: The imbalance in autonomic nervous system, characterized by increased sympathetic and attenuated parasympathetic activity, plays an important role in the pathogenesis of hypertension. The spontaneously hypertensive rats (SHR) which are one of the most studied animal models of essential hypertension, are characterized by autonomic nervous system imbalance. Our study was aimed to determine the effect of chronic inhibition of acetylcholinesterase with pyridostigmine on cardiovascular parameters and sympatho-vagal balance in SHR and Wistar-Kyoto (WKY) rats. Design and method: Adult male SHR and WKY rats were treated with pyridostigmine (25 mg/kg/day) in drinking solution for 2 weeks. The rats were implanted with telemetric transducers to measure blood pressure (BP) and heart rate (HR). Autonomic balance was evaluated by power spectral analysis of systolic blood pressure variability (SBPV) and heart rate variability (HRV). Sympatho-vagal balance was also evaluated pharmacologically by administration of methylatropine (antagonist of muscarinic acetylcholine receptors) and propranolol (antagonist of beta-adrenergic receptors) in a separate set of rats. Results: SHR have elevated BP, increased vascular sympathetic activity (low frequency component of SBPV), and reduced HRV compared to WKY. Pyridostigmine significantly reduced HR in rats of both strains (during both dark and light phase) and BP during the dark (active) phase compared to untreated controls. Acetylcholinesterase activity in plasma was significantly reduced by pyridostigmine treatment in both strains (SHR 53 ± 3%, WKY 46 ± 3%). Sympatho-vagal balance examination revealed reduced cardiac vagal tone in SHR as evidenced by blunted HR response to the muscarinic receptor blocker methylatropine and increased cardiac sympathetic tone as evidenced by elevated HR response to the beta-blocker propranolol. Pyridostigmine treatment increased cardiac vagal tone and decreased cardiac sympathetic tone in SHR to the levels of untreated WKY. Moreover, pyridostigmine increased HRV and reduced low frequency component of SBPV in SHR indicating the restoration of autonomic balance. The reduction of sympathetic tone in pyridostigmine-treated rats was also evident from the reduction of plasma levels of noradrenaline. The potentiation of cardiac parasympathetic activity by pyridostigmine treatment was confirmed by the attenuation of restraint stress-induced tachycardia in both strains. Conclusions: Chronic stimulation of peripheral cholinergic system with pyridostigmine leads to the improvement of autonomic nervous system balance in SHR by increasing cardiac vagal tone and reducing sympathetic tone. Thus, chronic treatment with acetylcholinesterase inhibitors seems to be a promising therapeutic strategy for the restoration of autonomic balance in cardiovascular diseases.

Influences of Intense Physical Effort on the Activity of the Autonomous Nervous System and Stress, as Measured with Photoplethysmography.

Background: The autonomic nervous system, which is composed of the sympathetic and parasympathetic nervous system, is closely related to the cardiovascular system. The temporal variation between each of the intervals between the consecutive “R” waves of an electrocardiogram is known as heart rate variability. Depending on the type of activity, both systems can be activated, and also influence the interval between “R” waves. Currently, with advancements in technology and electronic devices, photoplethysmography is used. Photoplethysmography detects changes in the intensity of reflected light that allow differentiation between systole and diastole and, therefore, determines the heart rate, its frequency and its variations. In this way, changes in the autonomic nervous system can be detected by devices such as the Max Pulse®. Objective: To determine whether the information provided by Max Pulse® on autonomic balance and stress is modified after intense physical exercise, thereby determining whether there is a relationship with body composition, and also whether there are differences with respect to gender. Materials and Methods: Fifty-three runners (38.9% female) with a mean age of 31.3 ± 8.1 years participated in the study. Two measurements (before and after intense physical effort) were performed with the Max Pulse® device. The flotoplethysmography measurement lasted 3 min, and was performed in the supine position. The exercise test was performed on a treadmill. It was initiated at a speed of 6 and 7 km/h for women and men, respectively. Subjects indicated the end of the test by making a hand gesture when unable to continue the test. Results: Autonomic nervous system activity and mental stress values decreased significantly (p < 0.05) in men and women, while autonomic nervous system balance decreased only in women. Physical stress increased (p < 0.05) in both sexes. Conclusions: Intense exercise causes changes in variables that assess autonomic nervous system balance and stress, as measured by a device based on photoplethysmography. The changes are evident in both sexes, and are not related to body composition.

Dynamic Electroneurostimulation in Rehabilitation: a Prospective Randomized Study of 60 Patients after Surgical Treatment of Colorectal Malignancies

INTRODUCTION. Surgical treatment of colorectal malignancies, while increasing overall survival often determines the persistence ofthe pain syndrome, causing a decrease in the quality of life of patients. Pain-relieving medicines have side-effects and complications,which determines the search for and introduction of non-medicinal technologies. AIM. To evaluate the effectiveness of incorporating dynamic electroneurostimulation in the rehabilitation of patients after surgicaltreatment for colorectal cancer to correct pain syndrome, autonomic dysfunction and quality of life indices. MATERIAL AND METHODS. 60 male and female patients aged between 35 and 65 with a verified diagnosis of the colon and rectummalignant neoplasms after surgical treatment were examined in the conditions of the outpatient oncological care center at the StateMedical Institution “City Clinical Hospital No. 2” (Novosibirsk). They were divided into 2 groups: the 1st group (the main group, n=40)in addition to standard therapy received a 15-day course of dynamic electroneurostimulation (DENS) performed with «NEURODENSPCM» device, the 2nd group (the comparison group, n=32) received a standard treatment including chemotherapy, symptomaticpharmacotherapy and exercise therapy. The examination included assessment of pain syndrome using validated pain scales, thevegetative status, anxiety and depression, quality of life parameters. RESULTS AND DISCUSSION. The patients of the 1st group showed 1.2- and 2.4 times reduction of algias by the 5th and 15th day ofrehabilitation respectively. Upon completion of the rehabilitation the autonomic nervous system balance index (LF/HF) was adjustedby 4.8 and the centralization index by 6.0 times against the baseline, the anxiety and depression index on the HADS scale was reducedby 1.5 times, the quality of life on the SF-36 scale improved: physical functioning by 1.5 times, pain by 1.2 times, general health by 1.5times, which differed from the similar indicators in the 2nd group.Dynamic electroneurostimulation using NEURODENS-PCM device can have pain-relieving and vegetative-regulating effects due toactivation of antinociceptive brain structures and influence on suprasegmental parts of the autonomic nervous system. CONCLUSION. The inclusion of dynamic electroneurostimulation using «NEURODENS-PCM» device in the rehabilitation of patientsafter surgical treatment of malignant neoplasms in the colorectal region enables a faster relief of pain syndrome, adjustment of theneurovegetative regulation and the anxiety level, which contributes to improvement of the ' quality of life of patients.

Are changes in pain associated with changes in heart rate variability in patients treated for recurrent or persistent neck pain?

BackgroundPersistent or recurrent neck pain is associated with perturbations in the autonomic nervous system balance, and nociceptive stimulation has been seen to influence this balance. However, very few prospective studies have addressed the extent to which changes in pain associate with changes in autonomic cardiac regulation. Therefore, we investigated if changes in pain vary with changes in heart rate variability in a cohort of patients treated for persistent or recurrent neck pain.MethodThis analysis is based on data from a randomized controlled trial in which participants were given home stretching exercises with or without spinal manipulative therapy for two weeks. As the effectiveness of the intervention (home stretching exercises and spinal manipulative therapy) was found to be equal to the control (home stretching exercises alone), all 127 participants were studied as one cohort in this analysis. During the intervention, pain levels were recorded using daily text messages, and heart rate variability was measured in the clinics three times over two weeks. Two approaches were used to classify patients based on changes in pain intensity: 1) Clinically important changes in pain were categorized as either "improved" or "not improved" and, 2) Pain development was measured using pain trajectories, constructed in a data driven approach. The association of pain categories and trajectories with changes in heart rate variability indices over time were then analysed using linear mixed models.ResultsHeart rate variability did not differ significantly between improved and not-improved patients, nor were there any associations with the different pain trajectories.ConclusionsIn conclusion, changes in pain after home stretching exercises with or without spinal manipulative therapy over two weeks were not significantly associated with changes in heart rate variability for patients with persistent or recurrent neck pain. Future studies should rely on more frequent measurements of HRV during longer treatment periods.Trial registrationThe trial was registered at ClinicalTrials.gov, registration number: NCT03576846.