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Whether part of the blood pressure lowering effects of glyceryl trinitrate (GTN) is the result of centrally mediated reduction in sympathetic activity is debated. In humans, baroreflex activity potentially obscures the central sympatholytic effects of GTN. We examined this in a routine clinical tilt test in a patient with baroreflex failure secondary to previous neck radiotherapy. With reduced baroreflex function we observed an exaggerated fall in blood pressure and reduced sympathetic activity with GTN, supporting a peripheral vasodilation and central sympatholytic effect. [ABSTRACT FROM AUTHOR]

Background: Stroke is a neurological disease that causes sudden loss of brain functions. One of the most important symptoms is hemiparesis, which due to the weakness of the trunk promotes a decrease in diaphragmatic power and impairs pulmonary function. In addition to the respiratory system, stroke can lead to impairment of the cardiovascular system. This occurs when the Autonomic Nervous System is affected, increasing the risk of the development of Heart Rate Variability due to sympathetic hyperactivity, this c ondition may predict an unfavorable prognosis after stroke. Case presentation: The aim of this study was to evaluate the variability of heart rate and respiratory muscle strength in a 61-year-old female patient diagnosed with a stroke three months prior to the study submitted to Neurofeedback training. That's the first report of this kind in the literature. Cardiopulmonary evaluation was performed with a focus on heart rate and respiratory muscle strength before and after an intervention with five brain training sessions using the Neurofeedback BrainLink LITE. Conclusion: After therapy, significant alterations in the Delta wave increase and reduction of the Alpha wave were observed, also changes in the Autonomic Nervous System parameters were observed, with reduct ion of the sympathetic activity and increase of the parasympathetic activity, along with that, a reduction in the stress index was observed. The intervention was still positive in the improvement of respiratory parameters, with an increase in the overall inspiratory muscle strength index (S-Index) and peak inspiratory flow (PIF). It is suggested that Neurofeedback is efficient in recovering functions related to Autonomic Nervous System and respiratory system. [ABSTRACT FROM AUTHOR]

Social anxiety is characterized by maladaptive anticipation, avoidance, and post-avoidance processes in response to perceived threats. Exaggerated sympathetic activation to threats is proposed to play a key role in social anxiety, but has received inconsistent empirical support. To clarify this issue, we characterized social anxiety-related differences in the time course of sympathetic activation as a function of threat certainty and threat avoidance. While skin conductance was measured, adults (18–30 years old) reporting clinically elevated (n = 34) or low (n = 33) social anxiety symptoms completed a behavioral paradigm involving threat anticipation and the opportunity to avoid conditioned threat and non-threats. During threat anticipation, both groups exhibited increasing conditioned sympathetic activation when threat was certain; however, the high social anxiety group exhibited less conditioned sympathetic activation to threats vs. non-threats compared to the low social anxiety group, irrespective of threat certainty. Following threat anticipation, the high social anxiety group exhibited greater avoidance of both threats and non-threats. Following threat avoidance, the high social anxiety group exhibited comparatively smaller and slower sympathetic recovery. Taken together, our results suggest that social anxiety is characterized by indiscriminate sympathetic activation to both threat and safety cues, which facilitates maladaptive avoidance behaviors and impairs sympathetic recovery. [ABSTRACT FROM AUTHOR]

Background: The effects of hyperventilation and hyperventilation in the context of periodic breathing (PB) on sympatho-vagal balance (SVB) and hemodynamics in conditions of decreased cardiac output and feedback resetting, such as heart failure (HF) or pulmonary arterial hypertension (PAH), are not completely understood. Objectives: To investigate the effects of voluntary hyperventilation and simulated PB on hemodynamics and SVB in healthy subjects, in patients with systolic HF and reduced or mid-range ejection fraction (HFrEF and HFmrEF) and in patients with PAH. Methods: Study participants (n = 20 per group) underwent non-invasive recording of diastolic blood pressure, heart rate variability (HRV), baroreceptor-reflex sensitivity (BRS), total peripheral resistance index (TPRI) and cardiac index (CI). All measurements were performed at baseline, during voluntary hyperventilation and during simulated PB with different length of the hyperventilation phase. Results: In healthy subjects, voluntary hyperventilation led to a 50% decrease in the mean BRS slope and a 29% increase in CI compared to baseline values (p < 0.01 and p < 0.05). Simulated PB did not alter TPRI or CI and showed heterogeneous effects on BRS, but analysis of dPBV revealed decreased sympathetic drive in healthy volunteers depending on PB cycle length (p < 0.05). In HF patients, hyperventilation did not affect BRS and TPRI but increased the CI by 10% (p < 0.05). In HF patients, simulated PB left all of these parameters unaffected. In PAH patients, voluntary hyperventilation led to a 15% decrease in the high-frequency component of HRV (p < 0.05) and a 5% increase in CI (p < 0.05). Simulated PB exerted neutral effects on both SVB and hemodynamic parameters. Conclusions: Voluntary hyperventilation was associated with sympathetic predominance and CI increase in healthy volunteers, but only with minor hemodynamic and SVB effects in patients with HF and PAH. Simulated PB had positive effects on SVB in healthy volunteers but neutral effects on SVB and hemodynamics in patients with HF or PAH. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated that muscle sympathetic nerve activity (MSNA) responses to isometric exercise differs between active and inactive limbs. Whether limb-dependent responses are characteristic of responses to the cold pressor test (CPT) remains to be established. Therefore, we tested the hypothesis that CPT-induced MSNA responses differ between affected and unaffected limbs such that MSNA in the affected lower limb is greater than MSNA responses in the contralateral lower limb and the upper limb. Integrated peroneal MSNA (microneurography) was measured in young healthy individuals (n = 10) at rest and during three separate 3-min CPTs: the microneurography foot, opposite foot, and opposite hand. Peak MSNA responses were extracted for further analysis, as well as corresponding hemodynamic outcomes including mean arterial pressure (MAP; Finometer). MSNA responses were greater when the microneurography foot was immersed in ice water than when the opposite foot was immersed (38 ± 18 vs 28 ± 16 bursts/100hb: P < 0.01). MSNA responses when the opposite hand was immersed were greater than both the microneurography foot (46 ± 22 vs 38 ± 18 bursts/100hb: P < 0.01) and opposite foot (46 ± 22 vs 28 ± 16 bursts/100hb: P ≤0.01). Likewise, MAP responses were greater during the hand CPT than the microneurography foot (99 ± 9 vs 96 ± 8 mmHg: P < 0.01) and opposite foot CPT (99 ± 9 vs 96 ± 9 mmHg: P < 0.01). These data indicate that (a) upper limbs and (b) immersed limbs elicit greater MSNA responses to the CPT than lower and/or non-immersed limbs., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aims: 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., Discussion: 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., Conclusion: 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., (© 2024 The Authors. CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Sympathetic transduction is the study of how impulses of sympathetic nerve activity (SNA) affect end-organ function. Recently, the transduction of resting bursts of muscle SNA (MSNA) has been investigated and shown to have a role in the maintenance of blood pressure through changes in vascular tone in humans. In the present study, we investigate whether directly recorded resting cardiac SNA (CSNA) regulates heart rate (HR), coronary blood flow (CoBF), coronary vascular conductance (CVC), cardiac output (CO) and mean arterial pressure. Instrumentation was undertaken to record CSNA and relevant vascular variables in conscious sheep. Recordings were performed at baseline, as well as after the infusion of a β-adrenoceptor blocker (propranolol) to determine the role of β-adrenergic signalling in sympathetic transduction in the heart. The results show that after every burst of CSNA, there was a significant effect of time on HR (n = 10, ∆: +2.1 ± 1.4 beats min -1 , P = 0.002) and CO (n = 8, ∆: +100 ± 150 mL min -1 , P = 0.002) was elevated, followed by an increase in CoBF (n = 9, ∆: +0.76 mL min -1 , P = 0.001) and CVC (n = 8, ∆: +0.0038 mL min -1  mmHg -1 , P = 0.0028). The changes in HR were graded depending on the size and pattern of CSNA bursts. The HR response was significantly attenuated after the infusion of propranolol. Our study is the first to explore resting sympathetic transduction in the heart, suggesting that CSNA can dynamically change HR mediated by an action on β-adrenoceptors. KEY POINTS: Sympathetic transduction is the study of how impulses of sympathetic nerve activity (SNA) affect end-organ function. Previous studies have examined sympathetic transduction primarily in the skeletal muscle and shown that bursts of muscle SNA alter blood flow to skeletal muscle and mean arterial pressure, although this has not been examined in the heart. We investigated sympathetic transduction in the heart and show that, in the conscious condition, the size of bursts of SNA to the heart can result in incremental increases in heart rate and coronary blood flow mediated by β-adrenoceptors. The pattern of bursts of SNA to the heart also resulted in incremental increases in heart rate mediated by β-adrenoceptors. This is the first study to explore the transduction of bursts of SNA to the heart., (© 2024 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Purpose: Sympathetic nerve activity towards muscle (MSNA) and skin (SSNA) regulates various physiological parameters. MSNA primarily functions in blood pressure and flow, while SSNA operates in thermoregulation. Physical and cognitive stressors have been shown to have effects on both types of sympathetic activity, but there are inconsistencies as to what these effects are. This article aims to address the discrepancies in the literature and compare MSNA and SSNA responses., Methods: Microelectrode recordings were taken from the common peroneal nerve in 29 participants: MSNA (n = 21), SSNA (n = 16) and both MSNA and SSNA (n = 8). Participants were subjected to four different 2-min stressors: two physical (isometric handgrip task, cold pressor test) and two cognitive (mental arithmetic task, Stroop colour-word conflict test), the latter of which saw participants separated into responders and non-responders to the stressors. It was hypothesised that the physical stressors would have a greater effect on MSNA than SSNA, while the cognitive stressors would operate conversely., Results: Peristimulus time histogram (PSTH) analysis showed the mental arithmetic task to significantly increase both MSNA and SSNA; the isometric handgrip task and cold pressor test to increase MSNA, but not SSNA; and Stroop test to have no significant effects on changing MSNA or SSNA from baseline. Additionally, stress responses did not differ between MSNA and SSNA in participants who had both sets of data recorded., Conclusions: This study has provided evidence to support the literature which claims cognitive stressors increase sympathetic activity, and provides much needed SSNA data in response to stressors., (© 2024. The Author(s).)

Although Gaussian white noise (GWN) inputs offer a theoretical framework for identifying higher-order nonlinearity, an actual application to the data of the neural arc of the carotid sinus baroreflex did not succeed in fully predicting the well-known sigmoidal nonlinearity. In the present study, we assumed that the neural arc can be approximated by a cascade of a linear dynamic (LD) component and a nonlinear static (NS) component. We analyzed the data obtained using GWN inputs with a mean of 120 mmHg and standard deviations (SDs) of 10, 20, and 30 mmHg for 15 min each in anesthetized rats ( n = 7). We first estimated the linear transfer function from carotid sinus pressure to sympathetic nerve activity (SNA) and then plotted the measured SNA against the linearly predicted SNA. The predicted and measured data pairs exhibited an inverse sigmoidal distribution when grouped into 10 bins based on the size of the linearly predicted SNA. The sigmoidal nonlinearity estimated via the LD-NS model showed a midpoint pressure (104.1 ± 4.4 mmHg for SD of 30 mmHg) lower than that estimated by a conventional stepwise input (135.8 ± 3.9 mmHg, P < 0.001). This suggests that the NS component is more likely to reflect the nonlinearity observed during pulsatile inputs that are physiological to baroreceptors. Furthermore, the LD-NS model yielded higher R 2 values compared with the linear model and the previously suggested second-order Uryson model in the testing dataset. NEW & NOTEWORTHY We examined the input-size dependence of the baroreflex neural arc transfer characteristics during Gaussian white noise inputs. A linear dynamic-static nonlinear model yielded higher R 2 values compared with a linear model and captured the well-known sigmoidal nonlinearity of the neural arc, indicating that the nonlinear dynamics contributed to determining sympathetic nerve activity. Ignoring such nonlinear dynamics might reduce our ability to explain underlying physiology and significantly limit the interpretation of experimental data.

Purpose: We have re-evaluated the anatomical arguments that underlie the division of the spinal visceral outflow into sympathetic and parasympathetic divisions., Methodology: Using a systematic literature search, we mapped the location of catecholaminergic neurons throughout the mammalian peripheral nervous system. Subsequently, a narrative method was employed to characterize segment-dependent differences in the location of preganglionic cell bodies and the composition of white and gray rami communicantes., Results and Conclusion: One hundred seventy studies were included in the systematic review, providing information on 389 anatomical structures. Catecholaminergic nerve fibers are present in most spinal and all cranial nerves and ganglia, including those that are known for their parasympathetic function. Along the entire spinal autonomic outflow pathways, proximal and distal catecholaminergic cell bodies are common in the head, thoracic, and abdominal and pelvic region, which invalidates the "short-versus-long preganglionic neuron" argument. Contrary to the classically confined outflow levels T1-L2 and S2-S4, preganglionic neurons have been found in the resulting lumbar gap. Preganglionic cell bodies that are located in the intermediolateral zone of the thoracolumbar spinal cord gradually nest more ventrally within the ventral motor nuclei at the lumbar and sacral levels, and their fibers bypass the white ramus communicans and sympathetic trunk to emerge directly from the spinal roots. Bypassing the sympathetic trunk, therefore, is not exclusive for the sacral outflow. We conclude that the autonomic outflow displays a conserved architecture along the entire spinal axis, and that the perceived differences in the anatomy of the autonomic thoracolumbar and sacral outflow are quantitative., (© 2024. The Author(s).)

Autonomic dysfunction is a common complication of type 2 diabetes mellitus (T2DM). However, the character of dysfunction varies in different reports. Differences in measurement methodology and complications might have influenced the inconsistent results. We sought to evaluate comprehensively the relationship between abnormal glucose metabolism and autonomic function at rest and the response to exercise in healthy individuals and T2DM patients. We hypothesized that both sympathetic and parasympathetic indices would decrease with the progression of abnormal glucose metabolism in individuals with few complications related to high sympathetic tone. Twenty healthy individuals and 11 T2DM patients without clinically evident cardiovascular disease other than controlled hypertension were examined. Resting muscle sympathetic nerve activity (MSNA), heart rate variability, spontaneous cardiovagal baroreflex sensitivity (CBRS), sympathetic baroreflex sensitivity and the MSNA response to handgrip exercise were measured. Resting MSNA was lower in patients with T2DM than in healthy control subjects (P = 0.011). Resting MSNA was negatively correlated with haemoglobin A 1c in all subjects (R = -0.45, P = 0.024). The parasympathetic components of heart rate variability and CBRS were negatively correlated with glycaemic/insulin indices in all subjects and even in the control group only (all, P < 0.05). In all subjects, the MSNA response to exercise was positively correlated with fasting blood glucose (R = 0.69, P < 0.001). Resting sympathetic activity and parasympathetic modulation of heart rate were decreased in relationship to abnormal glucose metabolism. Meanwhile, the sympathetic responses to handgrip were preserved in diabetics. The responses were correlated with glucose/insulin parameters throughout diabetic and control subjects. These results suggest the importance of a comprehensive assessment of autonomic function in T2DM., (© 2023 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

During parturition, cows often experience intense pain and stress, which increases the risk of inflammatory diseases. This study aimed to compare the postpartum health status between healthy cows and those diagnoses with inflammatory diseases by examining behavioral and heart rate (HR) variability (HRV) changes, to provide information before the onset of disease. Eight Holstein cows were used in this study. HR, parameters of HRV (low-frequency power: LF; high-frequency power: HF; LF/HF ratio, and total power) and time budget of individual maintenance behaviors (standing, recumbency, feeding, rumination while standing and lying, and sleep) were continuously recorded from 0 to 168 h postpartum. Milk and blood samples were collected daily. Cows were categorized as diseases based on the positive result of California mastitis test and/or serum haptoglobin concentration that exceeded 50 μg/ml after all blood samples have been collected. Compared to healthy individuals (n = 3), diseased cows (n = 5) exhibited higher HR, LF/HF, and lower total power (p < 0.05), suggesting the dominance of the sympathetic nervous system in cows with inflammatory diseases. Additionally, diseased cows showed an increased standing time budget and reduced recumbency (p < 0.05), which may be a behavioral strategy in response to discomfort from inflammation., (© 2024 Japanese Society of Animal Science.)

The cold pressor test (CPT) elicits strong cardiovascular reactions via activation of the sympathetic nervous system (SNS), yielding subsequent increases in heart rate (HR) and blood pressure (BP). However, little is known on how exposure to the CPT affects cardiac ventricular repolarization. Twenty-eight healthy males underwent both a bilateral feet CPT and a warm water (WW) control condition on two separate days, one week apart. During pre-stress baseline and stress induction cardiovascular signals (ECG lead II, Finometer BP) were monitored continuously. Salivary cortisol and subjective stress ratings were assessed intermittently. Corrected QT (QTc) interval length and T-wave amplitude (TWA) were assessed for each heartbeat and subsequently aggregated individually over baseline and stress phases, respectively. CPT increases QTc interval length and elevates the TWA. Stress-induced changes in cardiac repolarization are only in part and weakly correlated with cardiovascular and cortisol stress-reactivity. Besides its already well-established effects on cardiovascular, endocrine, and subjective responses, CPT also impacts on cardiac repolarization by elongation of QTc interval length and elevation of TWA. CPT effects on cardiac repolarization share little variance with the other indices of stress reactivity, suggesting a potentially incremental value of this parameter for understanding psychobiological adaptation to acute CPT stress.

Recent reports suggest that quantification of signal-averaged sympathetic transduction is influenced by resting muscle sympathetic nerve activity (MSNA) and burst occurrence relative to the average mean arterial pressure (MAP). Herein, we asked how these findings may influence age-related reductions in sympathetic transduction. Beat-to-beat blood pressure and MSNA were recorded during 5 min of rest in 27 younger (13 females: age, 25 ± 5 yr; BMI, 25 ± 4 kg/m 2 ) and 26 older (15 females: age, 59 ± 5 yr; BMI, 26 ± 4 kg/m 2 ) healthy adults. All MSNA bursts were signal averaged together. Beat-to-beat MAP values were then split into low (T1), middle (T2), and high (T3) tertiles, and signal-averaged transduction was calculated within each tertile. Resting MSNA was higher in older adults and MAP was similar between groups. Older adults exhibited blunted overall MAP transduction (younger, Δ1.5 ± 0.6 vs. older, Δ0.9 ± 0.7 mmHg; P = 0.005), which was irrespective of relation to prevailing MAP. A greater proportion of bursts occurred above the average MAP in older adults ( P < 0.001), and a larger proportion of these bursts were associated with depressor responses ( P = 0.005). Nonetheless, assessment of bursts above the average MAP associated with pressor responses revealed similar age-associated reductions in transduction (younger, Δ2.6 ± 1.6 vs. older, Δ1.7 ± 0.8 mmHg; P = 0.016). These findings indicate an age-related increase in burst occurrence above the average resting MAP, which alone does not explain blunted transduction, thereby supporting the physiological underpinnings of age-related decrements in sympathetic transduction to blood pressure. NEW & NOTEWORTHY The current study demonstrated that aging is associated with a greater prevalence of sympathetic bursts occurring above the average blood pressure, which offers both methodologically and physiologically relevant information regarding aging and sympathetic control of blood pressure. These data support age-related reductions in sympathetic transduction via a reduced pressor response to sympathetic bursts irrespective of the prevailing absolute blood pressure value, along with increases in sympathetic outflow necessary to maintain blood pressure.

Childhood and adolescence are salient periods for the development of adrenocortical and autonomic arms of the stress response system (SRS), setting the stage for subsequent health and adaptive functioning. Although adrenocortical and autonomic systems theoretically function in highly coordinated ways, the strength of the relationship between these systems remains unclear. We leveraged a multivariate mixed effects meta-analytic approach to assess associations between adrenocortical, sympathetic, and parasympathetic functioning at rest and reactivity during stress-inducing tasks across 52 studies (N = 7,671; 5-20 years old). Results suggested a modest positive relation between adrenocortical and sympathetic systems as well as between adrenocortical and parasympathetic systems. Moderation analyses indicated the strength of associations varied as a function of several methodological and sociodemographic characteristics. Environmental effects on cross-system regulation were less clear, perhaps due to underrepresentation of adverse-exposed youth in the included studies. Collectively, our findings call for greater methodological attention to the dynamical, non-linear nature of cross-system functioning, as well as the role of experience in their organization across development., Competing Interests: Conflicts of interest to declare: none.

Monitoring of high-risk patients in hospital wards is crucial in identifying and preventing clinical deterioration. Sympathetic nervous system activity measured continuously and non-invasively by Electrodermal activity (EDA) may relate to complications, but the clinical use remains untested. The aim of this study was to explore associations between deviations of EDA and subsequent serious adverse events (SAE). Patients admitted to general wards after major abdominal cancer surgery or with acute exacerbation of chronic obstructive pulmonary disease were continuously EDA-monitored for up to 5 days. We used time-perspectives consisting of 1, 3, 6, and 12 h of data prior to first SAE or from start of monitoring. We constructed 648 different EDA-derived features to assess EDA. The primary outcome was any SAE and secondary outcomes were respiratory, infectious, and cardiovascular SAEs. Associations were evaluated using logistic regressions with adjustment for relevant confounders. We included 714 patients and found a total of 192 statistically significant associations between EDA-derived features and clinical outcomes. 79% of these associations were EDA-derived features of absolute and relative increases in EDA and 14% were EDA-derived features with normalized EDA above a threshold. The highest F1-scores for primary outcome with the four time-perspectives were 20.7-32.8%, with precision ranging 34.9-38.6%, recall 14.7-29.4%, and specificity 83.1-91.4%. We identified statistically significant associations between specific deviations of EDA and subsequent SAE, and patterns of EDA may be developed to be considered indicators of upcoming clinical deterioration in high-risk patients., (© 2023. The Author(s).)

Purpose: The purpose of this was to compare effects of application of the skin stimulation method and topical anesthetic cream on pain, heart rate variability and satisfaction according to nursing intervention methods during arteriovenous fistula puncture in chronic renal failure hemodialysis patients. Methods: This study was a crossover design. Participants were 36 patients with chronic renal failure receiving hemodialysis treatment. Two forms of intervention were applied to participants, and then pain and heart rate variability were measured during the puncture. Results: There were no statistically significant differences according to each treatment in vein pain and artery pain. Also, there were no statistically significant differences according to each treatment in stress index, sympathetic activity (LF), parasympathetic activity (HF) and sympathetic activity/parasympathetic activity (LF/HF ratio). Satisfaction with application of skin stimulation method was statistically higher than that of topical anesthetic cream application. Conclusion: This suggests that application of the skin stimulation method complements disadvantages of topical anesthetic cream application and demonstrates possibility of application as a nursing intervention method which can be conveniently used by nurses in clinical practice. [ABSTRACT FROM AUTHOR]

Aims and Objectives/Purpose/Research Questions: Differences in how people regulate their emotions have been shown across cultures. Yet, whether bilinguals regulate emotions differently based on the language they are speaking is unknown, as is whether these regulatory choices relate to their physiology. The aim of this study was to assess whether self-reported use of emotion regulation strategies that promote emotional engagement would be associated with greater sympathetic arousal while describing emotional experiences for bilinguals. Design/Methodology/Approach: 99 Spanish–English bilinguals (M = 20.8 years; SD = 2.11; 73 women) were interviewed about times they felt sad and afraid in both Spanish and English, and described what they did to regulate those emotions. Sympathetic nervous system physiology (pre-ejection period; PEP) was assessed continuously. The within-person experimental design enabled exploration of differences in regulation and physiology that were associated with talking about negative emotions in different languages. Data and Analysis: Emotion regulation strategies that indexed emotional engagement (e.g. cognitive reappraisal) were reliably coded from participant interviews. PEP reactivity was calculated as the change from a resting baseline to each language context. We used hierarchical linear regressions to test our hypotheses. Findings/Conclusions: We found that using fewer engagement strategies was associated with decreased sympathetic arousal, but only for people who were more physiologically aroused when at rest and only when participants were speaking English. Originality: This study is the first to show that bilinguals' emotion regulatory attempts have different consequences across languages, highlighting how emotional processing is colored by cultural-linguistic lenses. Significance/Implications: These findings align with growing evidence that bilinguals' physiological reactions to emotional events depend on the language context. Knowledge generated by this investigation contributes to our understanding of cross-cultural differences in people's physiological arousal and emotional processing by highlighting these patterns among the understudied population of bilingual speakers. [ABSTRACT FROM AUTHOR]

This article reports on the added value of embodied responses identified through sympathetic nervous system (SNS) activity in couple therapy research. It focuses on moments of change and the timing of therapeutic interventions or therapeutic moves in a couple therapy session. The data for this single‐case study comprise couple therapy process videotapes recorded in a multi‐camera setting, and measurements of participants' SNS activity. The voluntary participants were a marital couple in their late thirties and two middle‐aged male psychotherapists. The division into topic segments showed how the key issue of seeking help, which was found to comprise three separate components, was repeatedly dealt with in the session. SNS activity showed different degrees of synchronization between the couple, between the therapists, and between the couple and therapists during the dialogue pertaining to these three components. The issue of timing emerged as a complex, even ambivalent, phenomenon. Arousal in the therapists was in line with their therapeutic activity, whereas in the clients it was more anticipatory. The approach used here rendered visible some of the intensity that therapeutic dialogue can generate when dealing with issues of relationship change in the couple context and showed how this intensity can be dialogically regulated in the therapeutic system. [ABSTRACT FROM AUTHOR]

The fraction of repolarization variability independent of RR interval variability is of clinical interest. It has been linked to direct autonomic nervous system (ANS) regulation of the ventricles in healthy subjects and seems to reflect the instability of the ventricular repolarization process in heart disease. In this study, we sought to identify repolarization measures that best reflect the sympathetic influences on the ventricles independent of the RR interval. ECG was recorded in 46 young subjects during supine and then following 45 degrees head-up tilt. RR intervals and five repolarization features (QTend, QTpeak, RTend, RTpeak, and TpTe) were extracted from the ECG recordings. Repolarization variability was separated into RR-dependent and RR-independent variability using parametric spectral analysis. Results show that LF power of TpTe is independent of RR in both supine and tilt, while the LF power of QTend and RTend independent of RR and respiration increases following tilt. We conclude that TpTe is independent of RR and is highly affected by respiration. QTend and RTend LF power might reflect the sympathetic influences on the ventricles elicited by tilt. Graphical abstract. [ABSTRACT FROM AUTHOR]

This case study reports the training of an elite 25-km open-water swimmer and the daily heart rate variability (HRV) changes during the 19-week period leading to his world champion title. Training load was collected every day and resting HRV was recorded every morning. The swimmer's characteristics were V̇O2max : 58.5 ml·min−1 ·kg−1 , maximal heart rate: 178 beats per minute, and maximal ventilation: 170 L·min−1. Weekly training volume was 85±21 km, 39±8% was at [La]b <2 mmol · L−1 (Z1), 53±8% was at [La]b 2–4 mmol·L−1 (Z2), and 8±4% was at [La]b >4 mmol·L−1 (Z3). In the supine position, the increase in training volume and Z2 training were related to increases in rMSSD and HF. In the standing position, an increase in parasympathetic activity and decrease in sympathetic activity were observed when Z1 training increased. Seasonal changes indicated higher values in the LF/HF ratio during taper, whereas higher values in parasympathetic indices were observed in heavy workload periods. This study reports extreme load of an elite ultra-endurance swimmer. Improvements in parasympathetic indices with increasing Z2 volume indicate that this training zone was useful to improve cardiac autonomic activity, whereas Z1 training reduced sympathetic activity. [ABSTRACT FROM AUTHOR]

• Negative stereotypes about women in math can threaten female college students. • Women engage more with female peers after feeling threatened than not. • Women do not engage more with male peers after feeling threatened than not. • Engagement was measured as asking questions and physiological linkage to peers. This research tests how experiencing stereotype threat before a dyadic interaction affects women's engagement with peers during a dyadic math task. In a pilot study (N = 167; M age = 20.1 years), women who completed a manipulation of stereotype threat (a socially evaluative math task in front of male evaluators) experienced greater subjective threat than did men. In Studies 1A and 1B, math-identified female undergraduates completed the stereotype threat or control (doing math alone) manipulation and then completed a collaborative math task with another female or male student (who completed the control task). Sympathetic nervous system responses were collected to measure physiological linkage—the effect of participants' physiological states on their partners' subsequent physiological states—as an indicator of attention to the partner. We also measured the number of math-related questions participants asked their partners and task performance. In Study 1A (female-female dyads; N = 104; M age = 19.9 years), threatened women asked more questions than controls did and became physiologically linked to their partners when those partners were speaking about math. Threatened women performed comparably to controls. In Study 1B (female-male dyads; N = 140; M age = 20.0 years), threatened women did not ask more questions of their male partners than controls did, nor did they show physiological linkage to their male partners. Women performed worse than men did, regardless of condition. When working with a female, experiencing stereotype threat outside of a working interaction leads women to engage more; this effect does not occur when with a male. [ABSTRACT FROM AUTHOR]

Background: Clinical response to left ventricular assist devices (LVADs), as measured by health-related quality of life, varies among patients after implantation; however, it is unknown which pathophysiological mechanisms underlie differences in clinical response by health-related quality of life. Objective: The purpose of this study was to compare changes in sympathetic markers (b-adrenergic receptor kinase-1 [bARK1], norepinephrine [NE], and 3,4-dihydroxyphenylglycol [DHPG]) between health-related quality of life clinical responders and nonresponders from pre-- to post--LVAD implantation. Methods:We performed a secondary analysis on a subset of data from a cohort study of patients from pre-- to 1, 3, and 6 months after LVAD implantation. Clinical response was defined as an increase of 5 points or higher on the Kansas City Cardiomyopathy Questionnaire Clinical Summary score from pre-- to6months post--LVAD implantation.We measured plasma bARK1 level with an enzyme-linked immunosorbent assay and plasma NE and DHPG levels with high-performance liquid chromatography with electrochemical detection. Latent growth curvemodeling was used to compare the trajectories ofmarkers between groups. Results: The mean (SD) age of the sample (n = 39) was 52.9 (13.2) years, and most were male (74.4%) and received LVADs as bridge to transplantation (69.2%). Preimplantation plasma bARK1 levels were significantly higher in clinical responders (n = 19) than in nonresponders (n = 20) (P = .001), but change was similar after LVAD (P = .235). Preimplantation plasma DHPG levels were significantly lower in clinical responders than in nonresponders (P = .002), but the change was similar after LVAD (P = .881). There were no significant differences in plasma NE levels. Conclusions: Preimplantation bARK1 and DHPG levels are differentiating factors between health-related quality of life clinical responders and nonresponders to LVAD, potentially signaling differing levels of sympathetic stimulation underlying clinical response. [ABSTRACT FROM AUTHOR]

Objective To analyze the clinical features of autonomic nerve dysfunction and sympathetic skin response (SSR) in patients with gout. Methods A total of 25 patients with gout diagnosed from March 2017 to January 2018 were enrolled, including 10 patients with tophus and 8 patients with autonomic nerve dysfunction (symptomatic). EMG was used to detect SSR. Results The main symptoms of autonomic nervous dysfunction in the gout group were abnormal sweat glands. Compared with the normal control group, the lower extremity latency period of patients in the gout group was prolonged (Z = -2.136, P = 0.033) and the amplitude was reduced (Z = -2.959, P = 0.003). Lower extremity amplitude of the symptomatic group was lower than that of the normal control group (Z = -3.426, P = 0.001) and the asymptomatic group (Z = -3.308, P = 0.001). The lower extremity amplitude of patients in tophout group was lower than that in the control group (Z = -3.176, P = 0.001) and the non-tophout group (Z = -2.301, P = 0.021), while the lower extremity latency period of patients without tophout was prolonged (Z = -2.518, P = 0.120) and the amplitude was reduced (Z = -2.327, P = 0.020), which were statistically significant different from the control group. Conclusions Abnormal autonomic nerve function exists in gout patients, mainly in lower limb injury, especially in patients with tophus or symptoms of autonomic nerve dysfunction. SSR can objectively evaluate the autonomic nerve function state. [ABSTRACT FROM AUTHOR]

Three recent renal denervation studies in both drug-naïve and drug-treated hypertensive patients demonstrated a significant reduction of ambulatory blood pressure compared with respective sham control groups. Improved trial design, selection of relevant patient cohorts, and optimized interventional procedures have likely contributed to these positive findings. However, substantial variability in the blood pressure response to renal denervation can still be observed and remains a challenging and important problem. The International Sympathetic Nervous System Summit was convened to bring together experts in both experimental and clinical medicine to discuss the current evidence base, novel developments in our understanding of neural interplay, procedural aspects, monitoring of technical success, and others. Identification of relevant trends in the field and initiation of tailored and combined experimental and clinical research efforts will help to address remaining questions and provide much-needed evidence to guide clinical use of renal denervation for hypertension treatment and other potential indications. [ABSTRACT FROM AUTHOR]

Phenomenological studies suggest the existence of enhanced cognitive states, termed flow or peak experiences, in which specific cognitive processes (e.g., attention, perception) can be dramatically increased for limited durations. Here we review new scientific evidence that shows that specific types of meditation that developed out of certain religious traditions such as Vajrayana (Tantric Buddhism) and Hindu Tantra lead to the enhanced cognitive states, characterized by heightened sympathetic activation and phasic alertness (a significant temporary boost in focused attention). This is in contrast to the meditation practices (Shamatha, Vipassana) from other traditions such as Theravada and Mahayana that elicit heightened parasympathetic activity and tonic alertness. Such findings validate Buddhist scriptural descriptions of heightened arousal during Vajrayana practices and a calm and alert state of mind during Theravada and Mahayana types of meditation. The finding demonstrates the existence of enhanced cognitive states—the unique and energized states of consciousness characterized by a dramatic boost in focused attention. [ABSTRACT FROM AUTHOR]

Infant--mother behavioral synchrony is thought to scaffold the development of self-regulation in the first years of life. During this time, infants' and mothers' physiological regulation may contribute to dyadic synchrony and, in infants, dyadic synchrony may support infants' physiological regulation. Because the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) serve different regulatory functions, the current study aimed to elucidate relations between infants' and mothers' SNS and PNS functioning and dyadic behavioral synchrony. Skin conductance (SC; SNS index), respiratory sinus arrhythmia (RSA; PNS index), heart period (HP; index of joint SNS and PNS arousal), and behavioral synchrony were assessed in 6-month-old infants (N = 140) and their mothers during a mild social stressor, the Face-to-Face Still-Face paradigm (Tronick, Als, Adamson, Wise, & Brazelton, 1978). Synchrony was related to infants' and mothers' PNS and to mothers' broad autonomic arousal but not to SNS-specific arousal. Higher levels of behavioral synchrony were associated with lower infant RSA but with higher mother HP and RSA at baseline and in each Face-to-Face Still-Face paradigm episode. Therefore, lower RSA infants may have required more synchronous engagement with mothers to support regulation, while higher RSA, less aroused mothers may have been particularly well-attuned to infants' emotions. Findings suggest that each individual's physiological state may contribute to the behavioral functioning of the dyad. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the response of local and distal skin temperature to moxibustion stimulation (MS) and explore the effects of MS on sympathetic nerve activity. The distal skin temperatures of fingertips, as an indicator for sympathetic reflex response, were recorded using infrared camera during resting period (10 min), MS period (10 min), and natural cooling period (15 min), respectively. The MS without ash cleaning (AC) was applied to acupoints Quze (PC3) (Group I) and Lao Gong (PC8) (Group II), respectively. In Group III, the MS with the operation of AC was performed on PC8. The temperature responses of the local stimulation points and corresponding control points were also investigated. At the beginning of MS period, a significant increase of temperature on the stimulation point accompanied by a simultaneous reduction of temperature on fingertips was observed. A marked negative correlation was also obtained between temperature changes in the stimulation point and in the fingertips. At the end of natural cooling period (t = 34 min), the temperature of stimulation point was obviously higher than baseline values. In contrast, the temperatures of fingertips increased and then returned to the baseline levels during the second minute of MS period. In Group III, the temperature of stimulation point increased every time with the operation of AC, accompanied by the temperature decrease of middle fingertip. The findings suggest that moxibustion may trigger the sympathetic nervous system and induce the reduction of microcirculation, accompanied by a reduction of fingertip temperature. In addition, the operation of AC caused repeated cycles of thermal stimulation on the stimulation point, which may repetitively activate cutaneous sympathetic nerve fibres and evoke the temperature reduction of fingertips. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Introduction: The acute blood pressure (BP) decrease is greater after evening than morning exercise, suggesting that evening training (ET) may have a greater hypotensive effect. Objective: This study aimed to compare the hypotensive effect of aerobic training performed in the morning versus evening in treated hypertensives. Methods: Fifty treated hypertensive men were randomly allocated to three groups: morning training (MT), ET, and control (C). Training groups cycled for 45 min at moderate intensity (progressing from the heart rate of the anaerobic threshold to 10% below the heart rate of the respiratory compensation point), while C stretched for 30 min. Interventions were conducted 3 times per week for 10 wk. Clinic and ambulatory BP and hemodynamic and autonomic mechanisms were evaluated before and after the interventions. Clinic assessments were performed in the morning (7:00–9:00 am) and evening (6:00–8:00 pm). Between–within ANOVA was used (P ≤ 0.05). Results: Only ET decreased clinic systolic BP differently from C and MT (morning assessment −5 ± 6 mm Hg and evening assessment −8 ± 7 mm Hg, P < 0.05). Only ET reduced 24 h and asleep diastolic BP differently from C and MT (−3 ± 5 and −3 ± 4 mm Hg, respectively, P < 0.05). Systemic vascular resistance decreased from C only in ET (P = 0.03). Vasomotor sympathetic modulation decreased (P = 0.001) and baroreflex sensitivity (P < 0.02) increased from C in both training groups with greater changes in ET than MT. Conclusions: In treated hypertensive men, aerobic training performed in the evening decreased clinic and ambulatory BP due to reductions in systemic vascular resistance and vasomotor sympathetic modulation. Aerobic training conducted at both times of day increases baroreflex sensitivity, but with greater after ET. [ABSTRACT FROM AUTHOR]

Background: No study has evaluated the cardiovascular effects of diazepam in elderly subjects that assume diazepam to induce sleep. Purpose: The present study was carried out in order to evaluate the effects of chronic administration of diazepam as hypnotic drug on blood pressure (BP) and heart rate (HR) in healthy elderly subjects. Patients and methods: Healthy, elderly subjects, aged 65–74 years, were treated with diazepam 5 mg or placebo—both administered once a day in the evening—for 4 weeks in two cross-over periods, each separated by a 2-week placebo period, according to a randomized, double-blind, cross-over design. At the end of each study period, clinical as well as 24-h ambulatory BP and HR were evaluated. Results: A total of 25 subjects were included in the analysis. At the end of a 4-week diazepam treatment, clinical as well 24-h BP and HR mean values were not significantly affected. Analysis of sub-periods showed that during night-time, systolic BP (SBP) values under diazepam were 7.6% higher than under placebo, with a mean difference of 7.9 mmHg (p < 0.01), diastolic BP (DBP) values were 5.8% higher, with a mean difference of 3.7 mmHg (p < 0.05 vs placebo) and HR values were 6.6% higher with a mean difference of 4.2 b/min (p < 0.05). The HR increase observed with diazepam persisted during the morning hours, whereas during the afternoon and evening hours SBP, DBP and HR values were similar in the two treatment groups. Conclusions: In elderly subjects chronic assumption of diazepam as hypnotic agent produced an increase in BP, in particular SBP, during night-time and of HR during night-time and morning hours. These effects, which probably depend on a diazepam-mediated increase in sympathetic drive and decrease in vagal tone, might be of clinical relevance due to the role of increased BP and HR as independent predictors of cardiovascular morbidity and mortality. [ABSTRACT FROM AUTHOR]

Cigarette smoking is one of the major causes of coronary heart disease with a thirty percent mortality rate in the United States. Cigarette smoking acting on the central nervous system (CNS) to stimulate the sympathetic nervous system (SNS) through, which facilitates the secretion of serotonin (5-HT) and catecholamines to supraphysiological levels in blood. The enhanced levels of 5-HT and catecholamines in smokers' blood are associated with increases in G protein-coupled receptor signaling and serotonylation of small GTPases, which in turn lead to remodeling of cytoskeletal elements to enhance granule secretion and promote unique expression of sialylated N -glycan structures on smokers' platelets. These mechanisms enhance aggregation and adhesion of smokers' platelets relative to those of non-smokers. This review focuses on the known mechanisms by which 5-HT and SERT, in coordinated signaling with catecholamines, impacts cigarette smokers' platelet biology. [ABSTRACT FROM AUTHOR]

Introduction/Purpose: We demonstrated that patients with obstructive sleep apnea (OSA) have reduced muscle metaboreflex control of muscle sympathetic nerve activity (MSNA). In addition, exercise training increased muscle metaboreflex control in heart failure patients. Objective: We tested the hypothesis that exercise training would increase muscle metaboreflex control of MSNA in patients with OSA. Methods: Forty-one patients with OSA were randomized into the following two groups: 1) nontrained (OSANT, n = 21) and 2) trained (OSAT, n = 20). Muscle sympathetic nerve activity was assessed by microneurography technique, muscle blood flow (FBF) by venous occlusion plethysmography, heart rate by electrocardiography, and blood pressure with an automated oscillometric device. All physiological variables were simultaneously assessed at rest, during isometric handgrip exercise at 30% of the maximal voluntary contraction, and during posthandgrip muscle ischemia (PHMI). Muscle metaboreflex sensitivity was calculated as the difference in MSNA between PHMI and the rest period. Patients in the OSAT group underwent 72 sessions of moderate exercise training, whereas patients in the OSANT group were clinical follow-up for 6 months. Results: The OSANT and OSAT groups were similar in anthropometric, neurovascular, hemodynamic and sleep parameters. Exercise training reduced the baseline MSNA (34 ± 2 bursts per minute vs 25 ± 2 bursts per minute; P < 0.05) and increased the baseline FBF (2.1 ± 0.2 mL·min−1 per 100 g vs 2.4 ± 0.2 mL·min−1 per 100 g; P < 0.05). Exercise training significantly reduced MSNA levels and increased FBF responses during isometric exercise. Exercise training significantly increased MSNA responses during PHMI (Δ6.5 ± 1 vs −1.7 ± 1 bursts per minute, P < 0.01). No significant changes in FBF or hemodynamic parameters in OSANT patients were found. Conclusions: Exercise training increases muscle metaboreflex sensitivity in patients with OSA. This autonomic change associated with increased muscle blood flow may contribute to the increase in exercise performance in this set of patients. [ABSTRACT FROM AUTHOR]

Abstract This article explores the dynamics of collaborative learning in the classroom from the perspective of the commonalities and interdependence in the degree of physiological activation from the sympathetic nervous system (i.e., sympathetic arousal) of group members. Using Empatica E4 wristbands, electrodermal activity—to derive arousal—was measured in 24 high school students working in groups of three (i.e., triads) during two runs of an advanced physics course. The participants met three times a week over six weeks for lessons of 75 min each. Most of the time (≈60–95% of the lesson) the triad members were at different arousal levels, and, when they were on the same level, it was mainly the low arousal (or deactivated) level. Less than 4% of the time were the triad members simultaneously in high arousal. Possible within-triad arousal contagion cases (71.3%) occurred mostly on a one-to-one basis and with a latency from within a few seconds up to 10 min, but usually within 1 min. This study supports the view that only small parts of group work are collaborative, as far as the synchronicity and coordination which collaboration presupposes. Although exploratory, results also illustrate the affordances of physiological measures to characterize collaborative processes. Highlights • Triad members are mostly at different arousal levels during collaborative learning. • If triad members are at the same arousal level, it is most commonly low arousal. • Within-triad sympathetic arousal contagion occurs mostly on a one-to-one basis. • Sympathetic arousal contagion latency ranges from within a few seconds up to 10 min. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the sleep quality, depression, anxiety, and autonomic function of a group of kidney-transplanted recipients who joined a combined exercise program (KTRt) or remained sedentary (KTRs). A total of 20 kidney-transplanted recipients, split into two groups (10 KTRt and 10 KTRs), joined the study. Heart rate variability, cardiorespiratory capacity, depression, and sleep questionnaires were evaluated. KTRt presented lower Pittsburgh Sleep Quality Index and greater entropy, and increased parasympathetic and decreased sympathetic modulation than KTRs. Anxiety level was minimal and depression was absent in both groups. KTRt group presented better sleep quality and better autonomic modulation than KTRs. [ABSTRACT FROM AUTHOR]

We investigated thermoregulatory and cardiovascular responses at rest in a temperate (20°C) and in a warm (30°C) environment (40% RH) without and with the application of capsaicin on the skin. We hypothesized that regardless of environmental temperature, capsaicin application would stimulate heat loss and concomitantly deactivate heat conservation mechanisms, thus resulting in rectal temperature (Tre) and mean blood pressure decline due to excitation of heat‐sensitive TRPV1. Ten male subjects were exposed, while seated, for 30 minutes to 20.8 ± 1.0°C or to 30.6 ± 1.1°C: without (NCA) and with (CA) application of capsaicin patches on the skin. Thermoregulatory (Tre, proximal‐distal skin temperature gradient) and cardiovascular variables (modelflow technique) as well as oxygen uptake were continuously measured. The area under the curve for Tre decline at 20°C was smaller in CA (−2.1 ± 1.3 a.u.) than in NCA (−0.6 ± 1.1 a.u., P < 0.01, r = 0.8). Likewise, at 30°C it was smaller in CA (−2.2 ± 2.1 a.u.) compared to NCA (−0.8 ± 2.0 a.u., P = 0.02, r = 0.7). Local vasomotor tone and oxygen uptake, were significantly lower by 36.7% ± 94.2% and 12.3% ± 12.3%, respectively, with capsaicin compared to NCA (P = 0.05 and P < 0.01, respectively). Additionally, in 30°C CA mean arterial pressure was lower by 10.7% ± 5.9%, 8.9% ± 5.9%, and 10.6% ± 7.0% compared to 30°C NCA, 20°C NCA, and 20°C CA, respectively (P < 0.01, P = 0.02, and P < 0.01, respectively, d = 1.4‐1.8). In conclusion, capsaicin application on the skin induced vasodilation and Tre decline. At 30°C CA, thermal responses were accompanied by arterial hypotension most likely due to the interactive effects of both stressors (warm environment and capsaicin) on cutaneous vascular regulation. [ABSTRACT FROM AUTHOR]

Muscle sympathetic nerve activity (MSNA) at rest increases with age. However, the influence of age on MSNA recorded during dynamic leg exercise is unknown. We tested the hypothesis that aging attenuates the sympatho-inhibitory response observed in young subjects performing mild to moderate 1-leg cycling. After predetermining peak oxygen uptake, we compared contra-lateral fibular nerve MSNA during 2 min each of mild (unloaded) and moderate (30%–40% of the work rate at peak oxygen uptake, halved for single leg) 1-leg cycling in 18 young (age, 23 ± 1 years (mean ± SE)) and 18 middle-aged (age, 57 ± 2 years) sex-matched healthy subjects. Mean height, weight, resting heart rate, systolic blood pressure, and percent predicted peak oxygen uptake were similar between groups. Middle-aged subjects had higher resting MSNA burst frequency and incidence (P < 0.001) and diastolic blood pressure (P = 0.04). During moderate 1-leg cycling, older subjects' systolic blood pressure increased more (+21 ± 5 vs. +10 ± 1 mm Hg; P = 0.02) and their fall in MSNA burst incidence was amplified (−19 ± 2 vs. −11 ± 2 bursts/100 heart beats; P = 0.01) but because heart rate rose less (+15 ± 3 vs. +19 ± 2 bpm; P = 0.03), exercise induced similar reductions in burst frequency (P = 0.25). Contrary to our initial hypothesis, with advancing age, mild- to moderate-intensity dynamic leg exercise elicits a greater rise in systolic blood pressure and a larger fall in MSNA. [ABSTRACT FROM AUTHOR]

An increase in sympathetic nervous system (SNS) activity or reactivity in response to stimulation is usually interpreted as an index of heightened maladaptive distress. However, sympathetic activation also underlies promptness to action, so it is not clear whether the same relation could stand for parental responses to infant cry given that a ready and prompt parental response to infant cry favors more adaptive cognitive, social, and emotional development in the infant. Previous studies have not been consistent in the interpretation of sympathetic activation which occurs in response to infant cry. We discuss these two opposing proposed interpretations. A possible alternative interpretation may be that medium activation of the SNS is adaptive because it prepares the organism to act promptly, whereas too low or too high SNS activation is maladaptive because it underlies a lack of empathetic reaction or a highly distressed response. [ABSTRACT FROM AUTHOR]

This study examined the effect of mild hypothermia (a 0.5 °C decrease in rectal temperature) on heart rate variability (HRV), with the identical hypothermia protocol performed twice and compared using intraclass correlation coefficient (r) analysis to study the repeatability. Twelve healthy males each completed 1 neutral (23 °C) and 2 cold (0 °C) trials. In the neutral trial, participants sat quietly for 30 min. In the cold trials, baseline data were obtained from a 5-min sample following 30 min of quiet sitting at 23 °C, followed by passive exposure to 0 °C; hypothermic measures were taken from a 5-min period immediately prior to rectal temperature decreasing by 0.5 °C. HRV was obtained from a 3-lead electrocardiogram. There were no differences (all p > 0.05) in baseline measures between the neutral and the 2 cold trials, suggesting no precooling anxiety related to the cold trials. Heart rate, together with HRV measures (i.e., root mean square difference of successive normal RR intervals, triangular interpolation of NN interval histogram, low-frequency oscillations (LF), and high-frequency oscillations (HF)), increased (all p < 0.05) with mild hypothermia and showed excellent reliability between the 2 cold trials (all r ≥ 0.81). In contrast, the LF/HF ratio decreased (p < 0.05) and had only fair reliability between the 2 cold trials (r = 0.551). In general, hypothermia led to increases in heart rate, together with most measures of HRV. Although it was counterintuitive that both sympathetic and vagal influences would increase simultaneously, these changes likely reflected increased stress from whole-body cooling, together with marked cardiovascular strain and sympathetic nervous system activity from shivering to defend core body temperature. An important methodological consideration for future studies is the consistent and repeatable HRV responses to hypothermia. [ABSTRACT FROM AUTHOR]

This investigation examined the effect of partial-body cryostimulation (PBC) performed in the recovery time between a strength training and an interval running (IR) session. Nine rugby players (age, 23.7 ± 3.6 years; body mass index, 28.0 ± 2.6 kg·m−2) were randomly exposed to 2 different conditions: (i) PBC: 3 min at −160 °C, and (ii) passive recovery at 21 °C. We performed the bioelectrical impedance analysis (BIA) and recorded temperature and cardiac autonomic variables at 3 time points: at baseline, after strength training, and after 90 min of recovery. In addition, blood lactate concentration was measured 1 min before and 2.5 min after the IR. Heart rate (HR), energy cost, minute ventilation, oxygen uptake, and metabolic power were assessed during the IR. Homeostatic hydration status was affected by the execution of an intense strength training subsession. Then, after PBC, the BIA vector was restored close to normohydration status. Autonomic variables changed over time in both conditions, although the mean differences and effect sizes were greater in the PBC condition. During IR, HR was 3.5% lower after PBC, and the same result was observed for oxygen uptake (∼4.9% lower) and ventilation (∼6.5% lower). The energy cost measured after cryotherapy was ∼9.0% lower than after passive recovery. Cryotherapy enhances recovery after a single strength training session, and during subsequent IR, it shows a reduction in cardiorespiratory and metabolic parameters. PBC may be useful for those athletes who compete or train more than once in the same day, to improve recovery between successive training sessions or competitions. [ABSTRACT FROM AUTHOR]

Sympathetic preganglionic neurons (SPNs) are the final output neurons from the central arm of the autonomic nervous system. Therefore, SPNs represent a crucial component of the sympathetic nervous system for integrating several inputs before driving the postganglionic neurons (PGNs) in the periphery to control end organ function. The mechanisms which establish and regulate baseline sympathetic tone and overall excitability of SPNs and PGNs are poorly understood. The SPNs are also known as the autonomic motoneurons (MNs) as they arise from the same progenitor line as somatic MNs that innervate skeletal muscles. Previously our group has identified a rich repertoire of homeostatic plasticity (HP) mechanisms in somatic MNs of the embryonic chick following in vivo synaptic blockade. Here, using the same model system, we examined whether SPNs exhibit similar homeostatic capabilities to that of somatic MNs. Indeed, we found that after 2-d reduction of excitatory synaptic input, SPNs showed a significant increase in intracellular chloride levels, the mechanism underlying GABAergic synaptic scaling in this system. This form of HP could therefore play a role in the early establishment of a setpoint of excitability in this part of the sympathetic nervous system. Next, we asked whether homeostatic mechanisms are expressed in the synaptic targets of SPNs, the PGNs. In this case we blocked synaptic input to PGNs in vivo (48-h treatment), or acutely ex vivo , however neither treatment induced homeostatic adjustments in PGN excitability. We discuss differences in the homeostatic capacity between the central and peripheral component of the sympathetic nervous system., Competing Interests: The authors declare no competing financial interests., (Copyright © 2023 Ratliff et al.)

New Findings: What is the topic of this review? Sympathoexcitation in both healthy and hypertensive pregnancies, and concurrent adaptations along the neurovascular cascade. What advances does it highlight? Known and plausible adaptations along the neurovascular cascade which may offset elevated MSNA in normotensive pregnancy while also highlighting knowledge gaps regarding understudied pathways., Abstract: The progression from conception through to the postpartum period represents an extraordinary period of physiological adaptation in the mother to support the growth and development of the fetus. Healthy, normotensive human pregnancies are associated with striking increases in both plasma volume and sympathetic nerve activity, yet normal or reduced blood pressure; it represents a unique period of apparent healthy sympathetic hyperactivity. However, how this normal blood pressure is achieved in the face of sympathoexcitation, and the mechanisms responsible for this increased activity are unclear. Importantly, sympathetic activation has been implicated in hypertensive pregnancy disorders - the leading causes of maternal-fetal morbidity and mortality in the developed world. An understudied link between pregnancy and the development of maternal hypertension may lie in the sympathetic nervous system regulation of blood pressure. This brief review presents the latest data on sympathoexcitation in both healthy and hypertensive pregnancies, and concurrent adaptations along the neurovascular cascade., (© 2022 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

CD8 + T cells are essential components of the immune response against viral infections and tumours, and are capable of eliminating infected and cancerous cells. However, when the antigen cannot be cleared, T cells enter a state known as exhaustion 1 . Although it is clear that chronic antigen contributes to CD8 + T cell exhaustion, less is known about how stress responses in tissues regulate T cell function. Here we show a new link between the stress-associated catecholamines and the progression of T cell exhaustion through the β 1 -adrenergic receptor ADRB1. We identify that exhausted CD8 + T cells increase ADRB1 expression and that exposure of ADRB1 + T cells to catecholamines suppresses their cytokine production and proliferation. Exhausted CD8 + T cells cluster around sympathetic nerves in an ADRB1-dependent manner. Ablation of β 1 -adrenergic signalling limits the progression of T cells towards the exhausted state in chronic infection and improves effector functions when combined with immune checkpoint blockade (ICB) in melanoma. In a pancreatic cancer model resistant to ICB, β-blockers and ICB synergize to boost CD8 + T cell responses and induce the development of tissue-resident memory-like T cells. Malignant disease is associated with increased catecholamine levels in patients 2,3 , and our results establish a connection between the sympathetic stress response, tissue innervation and T cell exhaustion. Here, we uncover a new mechanism by which blocking β-adrenergic signalling in CD8 + T cells rejuvenates anti-tumour functions., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

New Findings: What is the topic of this review? We review barosensory vessel mechanics and their role in blood pressure regulation across the lifespan. What advances does it highlight? In young normotensive men, aortic unloading mechanics contribute to the resting operating point of the vascular sympathetic baroreflex; however, with advancing age, this contribution is removed. This suggests that barosensory vessel unloading mechanics are not driving the well-documented age-related increase in resting muscle sympathetic nerve activity., Abstract: An age-associated increase in arterial blood pressure is evident for apparently healthy humans. This is frequently attributed to stiffening of the central arteries and a concurrent increase in sympathetic outflow, potentially mediated by a reduced ability of the baroreceptive vessels to distend. This is supported, in part, by a reduced mechanical component of the vascular sympathetic baroreflex (i.e., a reduction in distension for a given pressure). Previous characterization of the mechanical component has assessed only carotid artery distension; however, evidence suggests that both the aortic and carotid baroreflexes are integral to blood pressure regulation. In addition, given that baroreceptors are located in the vessel wall, the change in wall tension, comprising diameter, pressure and vessel wall thickness, and the mechanics of this change might provide a better index of the baroreceptor stimulus than the previous method used to characterize the mechanical component that relies on diameter alone. This brief review summarizes the data using this new method of assessing barosensory vessel mechanics and their influence on the vascular sympathetic baroreflex across the lifespan., (© 2023 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)