Heart rate variability, the vagus and calm.
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501 to 525 of 1,007Effects of heart rate variability biofeedback on cardiovascular responses and autonomic sympathovagal modulation following stressor tasks in prehypertensives.
Autonomic dysfunction is implicated in prehypertension, and previous studies have suggested that therapies that improve modulation of sympathovagal balance, such as biofeedback and slow abdominal breathing, are effective in patients with prehypertension at rest. However, considering that psychophysiological stressors may be associated with greater cardiovascular risk in prehypertensives, it is important to investigate whether heart rate variability biofeedback (HRV-BF) results in equivalent effects on autonomic cardiovascular responses control during stressful conditions in prehypertensives. A total of 32 college students with prehypertension were enrolled and randomly assigned to HRV-BF (n=12), slow abdominal breathing (SAB, n=10) or no treatment (control, n=10) groups. Then, a training experiment consisting of 15 sessions was employed to compare the effect of each intervention on the f…
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Smeets T (2010)MEDLINE-indexed journal, not yet read by usBiological psychology56 citations Autonomic and hypothalamic-pituitary-adrenal stress resilience: Impact of cardiac vagal tone.
Resilience refers to the ability to cope with stressful events. Variation in the activity of the stress-responsive sympatho-adrenal-medullary and hypothalamic-pituitary-adrenal axes is particularly important for adaptive stress responses and thus may give rise to individual differences in resilience. Here, we investigated whether cardiac vagal tone and adult attachment style are related to psychophysiological stress resilience by exposing a sample of healthy young men and women (n=68) to a laboratory stress test while monitoring autonomic (heart rate, salivary alpha-amylase), hypothalamic-pituitary-adrenal (salivary cortisol), and psychological stress levels. Our results demonstrate that adult attachment style did not influence autonomic, hypothalamic-pituitary-adrenal, or psychological stress responses. In contrast, higher resting cardiac vagal tone was associated with stress-induced in…
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Dimsdale JE (2008)reviewMEDLINE-indexed journal, not yet read by usJournal of the American College of Cardiology625 citations Psychological stress and cardiovascular disease.
There is an enormous amount of literature on psychological stress and cardiovascular disease. This report reviews conceptual issues in defining stress and then explores the ramifications of stress in terms of the effects of acute versus long-term stressors on cardiac functioning. Examples of acute stressor studies are discussed in terms of disasters (earthquakes) and in the context of experimental stress physiology studies, which offer a more detailed perspective on underlying physiology. Studies of chronic stressors are discussed in terms of job stress, marital unhappiness, and burden of caregiving. From all of these studies there are extensive data concerning stressors' contributions to diverse pathophysiological changes including sudden death, myocardial infarction, myocardial ischemia, and wall motion abnormalities, as well as to alterations in cardiac regulation as indexed by change…
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Cardiovascular complications of eating disorders.
Eating disorders (anorexia nervosa and bulimia) are associated with the highest mortality rate of any psychiatric disorder. Much of this mortality and morbidity stem from cardiovascular complications such as arrhythmia related to a prolonged QTc interval and/or electrolyte disorders, hypotension, and bradycardia. Structurally, the heart in patients with eating disorders is atrophic, which may relate to longstanding hypovolemia. These patients have low cardiac output and demonstrate increased peripheral vascular resistance despite the presence of hypotension. The treatment of eating disorders is incremental caloric feeding, which can have its own intrinsic cardiovascular risk (refeeding syndrome) manifested by arrhythmia, tachycardia, congestive heart failure, and sudden cardiac death. Patients will require close monitoring and slower refeedings to minimize the risk of these complications…
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Vagus Nerve as Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders.
The vagus nerve represents the main component of the parasympathetic nervous system, which oversees a vast array of crucial bodily functions, including control of mood, immune response, digestion, and heart rate. It establishes one of the connections between the brain and the gastrointestinal tract and sends information about the state of the inner organs to the brain via afferent fibers. In this review article, we discuss various functions of the vagus nerve which make it an attractive target in treating psychiatric and gastrointestinal disorders. There is preliminary evidence that vagus nerve stimulation is a promising add-on treatment for treatment-refractory depression, posttraumatic stress disorder, and inflammatory bowel disease. Treatments that target the vagus nerve increase the vagal tone and inhibit cytokine production. Both are important mechanism of resiliency. The stimulatio…
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Stress and Heart Rate Variability: A Meta-Analysis and Review of the Literature.
Objective: Physical or mental imbalance caused by harmful stimuli can induce stress to maintain homeostasis. During chronic stress, the sympathetic nervous system is hyperactivated, causing physical, psychological, and behavioral abnormalities. At present, there is no accepted standard for stress evaluation. This review aimed to survey studies providing a rationale for selecting heart rate variability (HRV) as a psychological stress indicator.
Methods: Term searches in the Web of Science®, National Library of Medicine (PubMed), and Google Scholar databases yielded 37 publications meeting our criteria. The inclusion criteria were involvement of human participants, HRV as an objective psychological stress measure, and measured HRV reactivity.
Results: In most studies, HRV variables changed in response to stress induced by various methods. The most frequently reported factor associated with…
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Heart rate variability in normal and pathological sleep.
Sleep is a physiological process involving different biological systems, from molecular to organ level; its integrity is essential for maintaining health and homeostasis in human beings. Although in the past sleep has been considered a state of quiet, experimental and clinical evidences suggest a noteworthy activation of different biological systems during sleep. A key role is played by the autonomic nervous system (ANS), whose modulation regulates cardiovascular functions during sleep onset and different sleep stages. Therefore, an interest on the evaluation of autonomic cardiovascular control in health and disease is growing by means of linear and non-linear heart rate variability (HRV) analyses. The application of classical tools for ANS analysis, such as HRV during physiological sleep, showed that the rapid eye movement (REM) stage is characterized by a likely sympathetic predominanc…
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Use of respiratory rates and heart rate variability in the assessment and treatment of children and adolescents with functional somatic symptoms.
Functional somatic symptoms (FSS) emerge when the stress system is activated in response to physical or emotional stress that is either chronic or especially intense. In such cases, the heightened state of physiological arousal and motor activation can be measured through biological markers. Our team have integrated the use of biological markers of body state - respiratory rate, heart rate (HR) and heart rate variability (HRV) measurements - as a way of helping families to understand how physical symptoms can signal activation of the body's stress systems. This study measured respiratory rates, HR and HRV in children and adolescents with FSS (and healthy controls) during baseline assessment to determine whether these biological markers were effective at differentiating patients with FSS. The study also implemented a biofeedback intervention during the assessment to determine whether pati…
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The physiological basis and measurement of heart rate variability in humans.
Cardiovascular variabilities were recognized over 250 years ago, but only in the past 20 years has their apparent utility come to be appreciated. Technological advancement has allowed precise measurement and quantification of short-term cardiovascular fluctuations; however, our understanding of the integrated mechanisms which underlie these oscillations is inadequate for their widespread application. Both autonomic branches, the parasympathetic and sympathetic nervous system, are key determinants of the magnitude of these spontaneous cardiovascular fluctuations. Heart rate variability can be an indicator of an individual cardiovascular condition. In this review, we will discuss the two primary rhythmic oscillations that underlie the complexity of the heart rate waveform. The first oscillation occurs over several cardiac cycles, is respiratory related, and termed respiratory sinus arrhyth…
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Harald M. Stauss (2003)reviewMEDLINE-indexed journal, not yet read by usAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology309 citations
Heart rate variability
IN FOCUSHeart rate variabilityHarald M. StaussHarald M. StaussDepartment of Exercise Science, University of Iowa, Iowa City, Iowa 52242Published Online:01 Nov 2003https://doi.org/10.1152/ajpregu.00452.2003MoreSectionsPDF (59 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations the rhythm of the heart has not only fascinated cardiologists but also inspired poets and musicians. Indeed, the periodic beat of the heart was used to define the speed of music. In music notation, the traditional Italian term "moderato" originally referred to one beat of the measure per walking pace (76-80 paces/min) or heartbeat (∼72 beats/min). The use of the heartbeat to define the speed of music may imply that the periodicity of the beat of the heart is very constant. However, this is not necessarily the case. In fact, loss of heart rate variability can indicate severe cardiovascu…
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Heart Rate and Breathing Are Not Always in Phase During Resonance Frequency Breathing.
For many years it has been an axiom among practitioners of heart rate variability biofeedback that heart rate and breathing vary in phase with each other when people do resonance frequency breathing. When people breathe at the frequency of the baroreflex system, about 0.1 Hz, heart rate and blood pressure have been found to oscillate 180° out of phase, while heart rate and breathing are in phase (zero-degree phase). Thus breathing stimulates the baroreflex by augmenting the baroreflex response with each breath, an effect that is magnified by resonance properties in the baroreflex system. The original data on these relationships came from a study of highly athletic healthy young people. To test this relationship we analyzed phase relationship data between cardiac interbeat interval and breathing during 5-min periods of resonance frequency breathing among 24 adults from a recent study of h…
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Neuromodulation in epilepsy: state-of-the-art approved therapies.
Three neuromodulation therapies have been appropriately tested and approved in refractory focal epilepsies: vagus nerve stimulation (VNS), deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS), and closed-loop responsive neurostimulation of the epileptogenic zone or zones. These therapies are primarily palliative. Only a few individuals have achieved complete freedom from seizures for more than 12 months with these therapies, whereas more than half have benefited from long-term reduction in seizure frequency of more than 50%. Implantation-related adverse events primarily include infection and pain at the implant site. Intracranial haemorrhage is a frequent adverse event for ANT-DBS and responsive neurostimulation. Other stimulation-specific side-effects are observed with VNS and ANT-DBS. Biomarkers to predict response to neuromodulation therapies are not available, and…
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Goldstein DS (2020)reviewMEDLINE-indexed journal, not yet read by usClinical autonomic research : official journal of the Clinical Autonomic Research Society100 citations The extended autonomic system, dyshomeostasis, and COVID-19.
The pandemic viral illness COVID-19 is especially life-threatening in the elderly and in those with any of a variety of chronic medical conditions. This essay explores the possibility that the heightened risk may involve activation of the "extended autonomic system" (EAS). Traditionally, the autonomic nervous system has been viewed as consisting of the sympathetic nervous system, the parasympathetic nervous system, and the enteric nervous system. Over the past century, however, neuroendocrine and neuroimmune systems have come to the fore, justifying expansion of the meaning of "autonomic." Additional facets include the sympathetic adrenergic system, for which adrenaline is the key effector; the hypothalamic-pituitary-adrenocortical axis; arginine vasopressin (synonymous with anti-diuretic hormone); the renin-angiotensin-aldosterone system, with angiotensin II and aldosterone the main eff…
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Learnings from 30 years of reported efficacy and safety of vagus nerve stimulation (VNS) for epilepsy treatment: A critical review.
Three decades after its introduction as an adjuvant therapeutic option in the management of selective drug-resistant epilepsy cases (DRE), vagus nerve stimulation (VNS) retains growing interest. An implantable device was first approved for epilepsy in Europe in 1994 and in the United States (US) in 1997. Subsequent modifications improved the safety and the efficacy of the system. The most recent application of vagal neurostimulation is represented by transcutaneous devices that are claimed to have strong therapeutic potential. In this review, we sought to analyze the most meaningful available data describing the indications, safety and efficacy of the different approaches of VNS in clinical practice. Therefore, we identified studies reporting VNS efficacy and/or safety in epilepsy and its comorbidities from January 1990 to February 2020 from various databases including PubMed, Scopus, Co…
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Vagus Nerve Stimulation for the Treatment of Epilepsy.
Vagus nerve stimulation (VNS) was the first neuromodulation device approved for treatment of epilepsy. In more than 20 years of study, VNS has consistently demonstrated efficacy in treating epilepsy. After 2 years, approximately 50% of patients experience at least 50% reduced seizure frequency. Adverse events with VNS treatment are rare and include surgical adverse events (including infection, vocal cord paresis, and so forth) and stimulation side effects (hoarseness, voice change, and cough). Future developments in VNS, including closed-loop and noninvasive stimulation, may reduce side effects or increase efficacy of VNS.
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Bioelectric neuromodulation for gastrointestinal disorders: effectiveness and mechanisms.
The gastrointestinal tract has extensive, surgically accessible nerve connections with the central nervous system. This provides the opportunity to exploit rapidly advancing methods of nerve stimulation to treat gastrointestinal disorders. Bioelectric neuromodulation technology has considerably advanced in the past decade, but sacral nerve stimulation for faecal incontinence currently remains the only neuromodulation protocol in general use for a gastrointestinal disorder. Treatment of other conditions, such as IBD, obesity, nausea and gastroparesis, has had variable success. That nerves modulate inflammation in the intestine is well established, but the anti-inflammatory effects of vagal nerve stimulation have only recently been discovered, and positive effects of this approach were seen in only some patients with Crohn's disease in a single trial. Pulses of high-frequency current appli…
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Imaging stress: an overview of stress induction methods in the MR scanner.
Processing of acute stress has potential implications for mental and physical health. At the same time, individuals differ largely in how strongly they react to stress. Neuroimaging paradigms have been developed to characterize the neural underpinnings of the stress response in general and to understand the mechanisms that differentiate high and low susceptible individuals. The goal of the present review was to summarize the current literature on psychosocial stress in the brain imaging environment. That is, we focused on the most common neuroimaging paradigms that have been used to induce acute stress and map out the questions that have been addressed with respect to the determinants, the consequences, and the processing of stress. We identified four major paradigms that have been used with different scientific aims. The Montreal Imaging Stress Test and the ScanSTRESS involve cognitive …
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The neurobiology of interoception in health and disease.
Interoception is the sensing of internal bodily sensations. Interoception is an umbrella term that encompasses (1) the afferent (body-to-brain) signaling through distinct neural and humoral (including immune and endocrine) channels; (2) the neural encoding, representation, and integration of this information concerning internal bodily state; (3) the influence of such information on other perceptions, cognitions, and behaviors; (4) and the psychological expression of these representations as consciously accessible physical sensations and feelings. Interoceptive mechanisms ensure physiological health through the cerebral coordination of homeostatic reflexes and allostatic responses that include motivational behaviors and associated affective and emotional feelings. Furthermore, the conscious, unitary sense of self in time and space may be grounded in the primacy and lifelong continuity of …
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Vagus nerve stimulation: Surgical technique of implantation and revision and related morbidity.
Indications for vagus nerve stimulation (VNS) therapy include focal, multifocal epilepsy, drop attacks (tonic/atonic seizures), Lennox-Gastaut syndrome, tuberous sclerosis complex (TSC)-related multifocal epilepsy, and unsuccessful resective surgery. Surgical outcome is about 50-60% for seizures control, and may also improve mood, cognition, and memory. On this basis, VNS has also been proposed for the treatment of major depression and Alzheimer's' disease. The vagus nerve stimulator must be implanted with blunt technique on the left side to avoid cardiac side effects through the classic approach for anterior cervical discectomy. The actual device is composed of a wire with three helical contacts (two active contacts, one anchoring) and a one-pin battery. VNS is usually started 2 weeks after implantation with recommended settings of stimulation (1.0-2.0 mA; 500 μs pulse width; 20-30 Hz; …
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Carreno FR, Frazer A (2017)reviewMEDLINE-indexed journal, not yet read by usNeurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics160 citations Vagal Nerve Stimulation for Treatment-Resistant Depression.
Major depressive disorder (MDD) is prevalent. Although standards antidepressants are more effective than placebo, up to 35% of patients do not respond to 4 or more conventional treatments and are considered to have treatment-resistant depression (TRD). Considerable effort has been devoted to trying to find effective treatments for TRD. This review focuses on vagus nerve stimulation (VNS), approved for TRD in 2005 by the Food and Drugs Administration. Stimulation is carried by bipolar electrodes on the left cervical vagus nerve, which are attached to an implanted stimulator generator. The vagus bundle contains about 80% of afferent fibers terminating in the medulla, from which there are projections to many areas of brain, including the limbic forebrain. Various types of brain imaging studies reveal widespread functional effects in brain after either acute or chronic VNS. Although more ran…
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Surgically implanted and non-invasive vagus nerve stimulation: a review of efficacy, safety and tolerability.
Vagus nerve stimulation (VNS) is effective in refractory epilepsy and depression and is being investigated in heart failure, headache, gastric motility disorders and asthma. The first VNS device required surgical implantation of electrodes and a stimulator. Adverse events (AEs) are generally associated with implantation or continuous on-off stimulation. Infection is the most serious implantation-associated AE. Bradycardia and asystole have also been described during implantation, as has vocal cord paresis, which can last up to 6 months and depends on surgical skill and experience. The most frequent stimulation-associated AEs include voice alteration, paresthesia, cough, headache, dyspnea, pharyngitis and pain, which may require a decrease in stimulation strength or intermittent or permanent device deactivation. Newer non-invasive VNS delivery systems do not require surgery and permit pat…
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Beauchaine TP (2015)reviewMEDLINE-indexed journal, not yet read by usJournal of clinical child and adolescent psychology : the official journal for the Society of Clinical Child and Adolescent Psychology, American Psychological Association, Division 53241 citations Future Directions in Emotion Dysregulation and Youth Psychopathology.
This article reviews central nervous system substrates and autonomic correlates of emotion dysregulation and offers several suggestions for future research. Studies conducted in the last two decades indicate that effective emotion regulation requires efficient top-down, cortically mediated regulation of bottom-up, subcortically mediated individual differences in trait impulsivity and trait anxiety. Without making critical distinctions between highly heritable individual differences in trait impulsivity and trait anxiety, versus less heritable and more socialized deficiencies in emotion regulation, progress in understanding the development of psychopathology among children and adolescents will be hampered. Future research can also be improved by measuring emotion dysregulation across multiple level of analysis, specifying physiological mechanisms through which operant reinforcement shapes…
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Sex hormones in the modulation of irritable bowel syndrome.
Compelling evidence indicates sex and gender differences in epidemiology, symptomatology, pathophysiology, and treatment outcome in irritable bowel syndrome (IBS). Based on the female predominance as well as the correlation between IBS symptoms and hormonal status, several models have been proposed to examine the role of sex hormones in gastrointestinal (GI) function including differences in GI symptoms expression in distinct phases of the menstrual cycle, in pre- and post-menopausal women, during pregnancy, hormonal treatment or after oophorectomy. Sex hormones may influence peripheral and central regulatory mechanisms of the brain-gut axis involved in the pathophysiology of IBS contributing to the alterations in visceral sensitivity, motility, intestinal barrier function, and immune activation of intestinal mucosa. Sex differences in stress response of the hypothalamic-pituitary-adrena…
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Vagus nerve stimulation…25 years later! What do we know about the effects on cognition?
VNS therapy was delivered to patients for the first time in 1988. After 25 years, insight in the antiepileptic and antidepressant mechanism of action of VNS has grown steadily. The effects on cognition and especially memory remain controversial. This review provides an elaborate overview of studies addressing cognition and describes potential underlying mechanisms for the reported effects. Short-term VNS has an effect on verbal memory recognition when administered at the correct timing and dosage. Chronic VNS resulted into a positive effect on the cognitive status in an Alzheimer population. Positive effect of chronic VNS in epilepsy or depression patients on global cognitive functioning are less convincing. Neither do the results reveal a negative effect which has major implications for chronic treatment of neurology patients. A cascade of neurochemical processes put in motion by change…
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Bright light therapy for depression: a review of its effects on chronobiology and the autonomic nervous system.
Bright light therapy (BLT) is considered among the first-line treatments for seasonal affective disorder (SAD), yet a growing body of literature supports its use in other neuropsychiatric conditions including non-seasonal depression. Despite evidence of its antidepressant efficacy, clinical use of BLT remains highly variable internationally. In this article, we explore the autonomic effects of BLT and suggest that such effects may play a role in its antidepressant and chronotherapeutic properties. After providing a brief introduction on the clinical application of BLT, we review the chronobiological effects of BLT on depression and on the autonomic nervous system in depressed and non-depressed individuals with an emphasis on non-seasonal depression. Such a theory of autonomic modulation via BLT could serve to integrate aspects of recent work centered on alleviating allostatic load, the p…
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