Higher Parasympathetic Activity Research Articles

Chronic inhibition of angiotensin converting enzyme lowers blood pressure in spontaneously hypertensive rats by attenuation of sympathetic tone: The role of enhanced baroreflex sensitivity

Spontaneously hypertensive rats (SHR) are characterized by sympathetic hyperactivity and insufficient parasympathetic activity, and their high blood pressure (BP) can be lowered by long-term inhibition of the renin-angiotensin system. The aim of our study was to determine the influence of chronic inhibition of angiotensin converting enzyme (ACE) by captopril on cardiovascular regulation by the sympathetic and parasympathetic nervous system. Implanted radiotelemetric probes or arterial cannulas were used to measure mean arterial pressure (MAP), heart rate (HR), and arterial baroreflex in adult SHR and Wistar-Kyoto (WKY) rats under basal or stress conditions. MAP and the low-frequency component of systolic blood pressure variability (LF-SBPV, marker of sympathetic activity) were greater in SHR than in WKY rats. Under basal conditions chronic captopril treatment reduced both parameters more effectively in SHR, and the same was true during acute restraint stress. HR was similar in control rats of both strains, but WKY rats showed greater heart rate variability (HRV), indicating higher parasympathetic activity. Captopril administration increased HR in both strains, whereas HRV was decreased only in WKY. Chronic captopril treatment improved the impaired baroreflex-HR control in SHR by increasing the sensitivity but not the capacity of vagal arm of arterial baroreflex. Captopril treatment attenuated BP changes elicited by dimethylphenylpiperazinium (DMPP, agonist of nicotinic acetylcholine receptors), especially in SHR, indicating that sympathetic nerve transmission is facilitated by angiotensin II more in hypertensive than in normotensive animals. Thus, chronic ACE inhibition improves baroreflex sensitivity and lowers BP through both central and peripheral attenuation of sympathetic tone.

Cardiovascular Autonomic Control During Hibernation in American Black Bears

The dramatic early decrease in HR upon entry into torpor in small hibernators has recently been shown to be associated with a marked increase in cardiac parasympathetic activity as indicated by increased short term beat to beat heart rate variability (RMSSD) normalized to average R-R interval (RMDSSD/RR, Zanetti et al 2023). At steady state torpor, as their body temperature drop to ~2°C, small hibernators benefit from the Q10 effect on cardiac pacemaker cells in maintaining a low HR with a reduced parasympathetic activity. Black bears in hibernation maintain body temperatures between 30-35°C while suppressing metabolism by 75% and with a marked decrease in HR from non-hibernating 55 bpm to hibernating 6-12 bpm including extreme respiratory sinus arrhythmia (Tøien et al 2011). As hibernating bears would not significantly benefit from the Q10 effect on cardiac pacemaker cells to sustain a low HR, we hypothesized that an elevated cardiac parasympathetic tone is needed to suppress HR. Continuous electrocardiogram (ECG) and blood pressure (BP) were recorded with implantable telemetry transmitters (DSI D70-CCP/EET and Konigsberg T28F-14B) in American black bears. A Pan-Tomkins algorithm modified for R-wave detection with long R-R intervals followed by visual inspection was used for the analysis. RMDSSD/RR for a 2 hour period in mid hibernation with no activity was 3 times higher than that during the resting phase in non-hibernation (0.68 vs. 0.23, n=10 and 7 respectively, p<0.001), confirming the presence of a high parasympathetic tone during hibernation. HR decreased from 68.3 ± 5.8 bpm to 12.9 ± 0.9 bpm (±SE, p<0.0001). RMSSD/RR during a 10 min period recovering from anesthesia (Telazol with supplemental Ketamin) during hibernation in mid March was only 0.019 ± 0.008 vs 0.58 ± 0.14 during a 10 min period before disturbance to induce anesthesia and HR 87.0 ± 8.7 b/min vs. 16.3 ± 1.4 b/min, demonstrating a parasympatholytic effect (n=6, p< 0.0006). The longest R-R intervals during extreme sinus arrhythmia detected in mid hibernation ranged from 11.8 to 33.0 s (Mean 19.0 ± 2.7, n=21). BP typically increased to above 200 mmHg during periods of rapid heart beats, and decayed slowly to 50-60 mmHg at the end of the longest R-R intervals. Analysis of data from a single bear from 2 hour periods at 2 week intervals throughout hibernation and recovery indicates that a high parasympathetic activity is maintained throughout hibernation and strongly correlated to the maximum observed R-R interval. We conclude that opposed to small hibernators, hibernating bears sustain low HR in hibernation with high parasympathetic activity controlling the extreme sinus arrhythmia. We suggest that BP is maintained during long R-R intervals by peripheral vasoconstriction. Supported by NIH COBRE grant number [P20GM130443]. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Association between heart rate variability and cardiorespiratory fitness in individuals with type 2 diabetes mellitus

Background: Type 2 Diabetes Mellitus (T2DM) is associated with cardiovascular risk, which is partly due to autonomic dysfunction and decreased cardiorespiratory fitness. This study examines the relationship between heart rate variability (HRV) and maximal oxygen uptake (VO2max) in T2DM patients to understand their interconnected impacts on autonomic and aerobic functions. Methods: In a cross-sectional study, 77 T2DM patients underwent HRV and VO2max assessments using standard protocols. HRV metrics were analysed in conjunction with VO2max, measured through direct breath-by-breath analysis. Pearson's correlation coefficient was used to investigate the relationships between HRV indices and VO2max. Results: VO2max showed strong positive correlations with RMSSD (r = 0.89, p < .001), HF (r = 0.54, p < .001), and pNN50% (r = 0.52, p < .001), indicating higher parasympathetic activity with improved cardiorespiratory fitness. Negative correlations with LF (r = -0.60, p < .001) and the LF/HF ratio (r = -0.39, p < .001) suggested that better fitness levels lead to sympathetic withdrawal and a more favourable autonomic balance. Moderate positive correlations with SDNN (r = 0.46, p < .001) and TP (r = 0.58, p < .001) further suggested that overall autonomic modulation is enhanced with increased cardiorespiratory fitness. Conclusion: This study substantiates a significant correlation between HRV and VO2max in individuals with T2DM, highlighting the intricate relationship between autonomic function and aerobic capacity. These findings suggest that enhancing cardiorespiratory fitness may improve autonomic balance, offering potential avenues for mitigating cardiovascular risk in the T2DM population.

Acute effects of different Tai Chi practice protocols on cardiac autonomic modulation

Tai Chi serves as an effective exercise modality for enhancing autonomic regulation. However, a majority of existing studies have employed the single routine (SR) protocol as the basis for health interventions. The extent to which the gong routine application (GRA) protocol achieves similar levels of exercise load stimulation as traditional single practice routines remains uncertain. Therefore, this study the distinct characteristics of autonomic load stimulation in these different protocols, thus providing a biological foundation to support the development of Tai Chi health promotion intervention programs. we recruited a cohort of forty-five university students to participate in the 15 min GRA protocol and SR protocol. We collected heart rate and heart rate variability indicators during periods of rest, GRA protocol, and SR protocol utilizing the Polar Scale. Additionally, we assessed the mental state of the participants using the BFS State of Mind Scale. In summary, the autonomic load is lower in the GRA protocol compared to the SR protocol, with lower sympathetic activity but higher parasympathetic activity in the former. Results are specific to college students, additional research is necessary to extend support for frail older adults. It is advised to incorporate GRA protocol alongside SR protocol in Tai Chi instruction. This approach is likely to enhance Tai Chi skills and yield greater health benefits.

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

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

Home-Based Dynamics of Sleepiness-Related Conditions Starting at Biological Evening and Later (Beyond Working).

Shift work requires round-the-clock readiness to perform professional duties, and the workers' performance highly depends on their sleepiness level, which can be underestimated during a shift. Various factors, including the time of day, can influence sleepiness in shift workers. The objective of this study was to explore the dynamics of sleepiness-related conditions assessed through heart rate variability analysis, starting from the biological evening and continuing in vivo (at home), without the need for artificial alertness support. The participants solely performed regular evening household duties. A total of 32 recordings were collected from the Subjective Sleepiness Dynamics Dataset for analysis. At 8:00 p.m. and every 30 min thereafter, the participants completed cyclic sleepiness scales (the KSS and the SSS) until the time they went to bed, while their heart rate was recorded. The results of the study indicated that during the biological evening, high sleepiness is associated with a 'stressed' condition characterized by higher sympathetic activation. Later on, it is associated with a 'drowsy' condition characterized by higher parasympathetic activation and a decline in heart rate variability. Our findings provide evidence that the type of condition experienced during high sleepiness depends on the biological time. This should be taken into account when managing work regimes in shift work and developing alertness detectors.

The effect of paired associative stimulation with a high-intensity cortical component and a high-frequency peripheral component on heart rate and heart rate variability in healthy subjects.

A novel protocol for paired associative stimulation (PAS), called high PAS, consists of high-intensity transcranial magnetic stimulation (TMS) and high-frequency peripheral nerve stimulation (PNS). High PAS was developed for spinal cord injury rehabilitation and targets plastic changes in stimulated pathways in the corticospinal tract, which improves motor function. As therapy interventions can last many weeks, it is important to fully understand the effects of high PAS, including its effect on the cardiovascular system. Heart rate variability (HRV) has been used to measure changes in both sympathetic and parasympathetic systems. We used short-term HRV measurements to evaluate the effects of one 20-min session of high PAS on 17 healthy individuals. HRV was recorded for 5 min before (PRE), during (STIM), immediately after (POST), 30 min after (POST30), and 60 min after (POST60) the stimulation. Five participants repeated the HRV setup with sham stimulation. A significant decrease in low-frequency (LF) power (n.u.) (p = 0.002), low-frequency to high-frequency (HF) ratio (p = 0.017), in Poincaré plot [the standard deviation of RR intervals perpendicular to (SD1) and along (SD2) the line of identity SD2/SD1 ratio p < 0.001], and an increase in HF power (n.u.) (p = 0.002) were observed between PRE and STIM conditions; these changes were fully reversible immediately after stimulation. PRE to POST by 3% (p = 0.015) and continued to decline until POST60 by 5% (p = 0.011). LF power (ms2) (p = 0.017) and SD2 (p = 0.015) decreased from PRE to STIM and increased from PRE to POST (p = 0.025 and p = 0.017, respectively). The results from sham PAS exhibited a trend similar to active high-PAS stimulation. High PAS does not have sustained effects during 60-min follow-up on cardiovascular functions, as measured by HRV. None of the short-term results indicates activation of the sympathetic nervous system in healthy individuals. Observed changes in HRV indicate higher parasympathetic activity during stimulation, which is reversible, and is plausibly explained by the fact that the participants spend 20 min without moving, talking, or using phones while being stimulated.

Maternal physiological calming responses to infant suckling at the breast

The mother–infant relation is key to infant physical, cognitive and social development. Mutual regulation and cooperation are required to maintain the dyadic system, but the biological foundation of these responses remains to be clarified. In this study, we report the maternal calming responses to infant suckling during breastfeeding. Using behavioral measures and a Holter electrocardiogram as a readout of the maternal autonomic nervous system, the maternal activities during resting, sitting with her infant on her lap, and breastfeeding were assessed. We found that during breastfeeding, mothers talked less and maternal heart rate was lower than during sitting with the infant without breastfeeding. Congruently, maternal heart rate variability measurements indicated a higher parasympathetic activity during breastfeeding. Time-locked analyses suggested that this maternal calming response was initiated by the tactile stimulation at the breast by the infant face or mouth latch, which preceded the perceived milk ejection. These findings suggest that somatosensory stimuli of breastfeeding activate parasympathetic activity in mothers. Just as how the infant Transport Response facilitates the carrying of infants, the maternal calming responses during breastfeeding may promote efficient milk intake by inhibiting spontaneous maternal activities.

Left- vs right-sided migraine: a scoping review

Migraine is a historically unilateral head pain condition, the cause of which is not currently known. A growing body of literature suggests individuals who experience migraine with left-sided headache ("left-sided migraine") may be distinguished from those who experience migraine with right-sided headache ("right-sided migraine"). In this scoping review, we explore migraine unilaterality by summarizing what is currently known about left- and right-sided migraine. Two senior medical librarians worked with the lead authors to construct and refine a set of search terms to identify studies of subjects with left- or right-sided migraine published between 1988, which is the year of publication of the first edition of the International Classification of Headache Disorders (ICHD), and December 8, 2021 (the date the searches were conducted). The following databases were searched: Medline, Embase, PsycINFO, PubMed, Cochrane Library, and Web of Science. Abstracts were loaded into Covidence review software, deduplicated, then screened by two authors to determine study eligibility. Eligible studies were those involving subjects diagnosed with migraine (according to ICHD criteria) in which the authors either: a) compared left- to right-sided migraine; or b) described (with analysis) a characteristic that differentiated the two. Data were extracted by the lead author, including ICHD version, the definition of unilateral migraine used by the authors, sample size, whether the findings were collected during or between attacks, and their key findings. The key findings were grouped into the following themes: handedness, symptoms, psychiatric assessments, cognitive testing, autonomic function, and imaging. After deduplication, the search yielded 5428 abstracts for screening. Of these, 179 met eligibility criteria and underwent full text review. 26 articles were included in the final analysis. All of the studies were observational. One study was performed during attack, nineteen between attacks, and six both during and between attacks. Left- and right-sided migraine were found to differ across multiple domains. In several cases, reciprocal findings were reported in left- and right-migraine. For example, both left- and right-sided migraine were associated with ipsilateral handedness, tinnitus, onset of first Parkinson's symptoms, changes in blood flow across the face, white matter hyperintensities on MRI, activation of the dorsal pons, hippocampal sclerosis, and thalamic NAA/Cho and NAA/Cr concentrations. In other cases, however, the findings were specific to one migraine laterality. For example, left-sided migraine was associated with worse quality of life, anxiety, bipolar disorder, PTSD, lower sympathetic activity, and higher parasympathetic activity. Whereas right-sided migraine was associated with poorer performance on multiple cognitive tests, a greater degree of anisocoria, changes in skin temperature, higher diastolic blood pressure, changes in blood flow through the middle cerebral and basilar arteries, and changes on EEG. Left- and right-sided migraine differed across a wide range of domains, raising the possibility that the pathophysiology of left- and right-migraine may not be identical.

Can resting heart rate explain the heart rate and parasympathetic responses during rest, exercise, and recovery?

The effect of resting heart rate (RHR) on the heart rate (HR) dynamics and parasympathetic modulation at rest, exercise, and recovery remain to be clarified. This study compares HR and parasympathetic responses at rest, during submaximal exercise testing and recovery in young, physically active men with different RHR average values. HR and parasympathetic responses were compared between two groups: bradycardia group-RHR < 60 bpm (BG, n = 20) and normocardia group-RHR ≥ 60 ≤ 100 bpm (NG, n = 20). A Polar RS800® was used to record the RR-interval series and HR at rest in the supine position, following the postural change (from supine to orthostatic position) and in the orthostatic position for 5 minutes, as well as during and after a submaximal exercise testing. Statistical analysis employed the MANOVA, Mann-Whitney, and Simple Linear regression test with a two-tailed p-value set at ≤ 0.05. BG at rest showed lower HR in the orthostatic position, higher parasympathetic activity in the supine and orthostatic positions, and higher parasympathetic reactivity than NG (p ≤ 0.01) after the postural change. BG before exercise showed lower HR and higher values of the chronotropic reserve and parasympathetic withdrawal than NG (p ≤ 0.01) throughout the exercise. Following the exercise, BG showed higher values of HR recovery (HRR) and parasympathetic reactivation in the 3rd and 5th minutes of recovery than NG (p ≤ 0.01). Lastly, the RHR can explain the variance of the HR at rest, during exercise testing, and recovery from 11 to 48%. We concluded that BG (RHR < 60 bpm) showed higher chronotropic and parasympathetic modulation at rest, higher chronotropic reserve, parasympathetic withdrawal during the submaximal exercise test, and faster HRR and parasympathetic reactivation after effort in young physically active men.

Cardiac autonomic nervous activity in patients with transposition of the great arteries after arterial switch operation

BackgroundA chronic imbalance of the autonomic nervous system(ANS) may contribute to long term complications in different congenital heart diseases. The purpose of this study was to determine whether the ANS plays a role in the long-term outcome of patients with Transposition of great arteries(TGA) after arterial switch operation(ASO) as its contribution is as yet not clear. MethodsThe ANS activity was evaluated non-invasively in 26 TGA patients and 52 age-appropriate healthy subjects combining impedance cardiography and electrocardiography. Heart rate, pre-ejection period(sympathetic activity parameter) and respiratory sinus arrhythmia and the root of the mean square of successive normal-to-normal interval differences(parasympathetic activity parameter) were measured during 5 different daily activities(sleep, sitting, active sitting, light and moderate/vigorous physical activity). Whether the ANS activity was related to ventricular function, exercise test performance or clinical outcome in the patient group was also analyzed. ResultsCompared to healthy subjects: heart rate was significantly lower in TGA patients at rest and during quiet and active sitting; sympathetic activity was significantly reduced in patients during physical activity; and the parasympathetic activity was higher in TGA patients while quiet and active sitting. In the patient group a significant positive correlation between 4-chamber longitudinal strain and parasympathetic activity during 3 different daily activities was found. ConclusionsThe sympathetic nervous system response to physical activity is reduced in TGA patients after ASO. Additionally, we observed a positive correlation between better left ventricular function and higher parasympathetic activity that could be in line with the known protective effect of a higher vagal activity.

Endurance training-induced cardiac remodeling in a guinea pig athlete's heart model.

Besides the health benefits of regular exercise, high-level training-above an optimal level-may have adverse effects. In this study, we investigated the effects of long-term vigorous training and its potentially detrimental structural-functional changes in a small animal athlete's heart model. Thirty-eight 4-month-old male guinea pigs were randomized into sedentary and exercised groups. The latter underwent a 15-week-long endurance-training program. To investigate the effects of the intense long-term exercise, in vivo (echocardiography, electrocardiography), ex vivo, and in vitro (histopathology, patch-clamp) measurements were performed. Following the training protocol, the exercised animals exhibited structural left ventricular enlargement and a significantly higher degree of myocardial fibrosis. Furthermore, resting bradycardia accompanied by elevated heart rate variability occurred, representing increased parasympathetic activity in the exercised hearts. The observed prolonged QTc intervals and increased repolarization variability parameters may raise the risk of electrical instability in exercised animals. Complex arrhythmias did not occur in either group, and there were no differences between the groups in ex vivo or cellular electrophysiological experiments. Accordingly, the high parasympathetic activity may promote impaired repolarization in conscious exercised animals. The detected structural-functional changes share similarities with the human athlete's heart; therefore, this model might be useful for investigations on cardiac remodeling.

Heart Rate Variability and Pain: A Systematic Review.

Background and Objective: Heart rate variability (HRV) as an index of the autonomic nervous system appears to be related to reactivity to experimental pain stimuli. HRV could better explain the contributions of sympathetic and parasympathetic activity response to nociceptive stimulation. The aim of this study was to systematically review and synthesize the current evidence on HRV in relation to the experience of pain in experimental tasks. Databases and Data Treatment: Studies indexed in the PubMed, PsycINFO, MEDLINE, WebOfScience, and Scopus databases were reviewed for eligibility. Studies on the autonomic response (i.e., HRV) to experimentally induced pain in healthy adults were included. Different methods of pain induction were considered (e.g., thermal, pressure, and electrical). Data were synthesized considering the association between HRV and both pain induction and subjective measures of pain. Results: Seventy-one studies were included. The results underline significant change in both the sympathetic and parasympathetic autonomic nervous systems during the painful stimulation independent of the pain induction method. The autonomic reaction to pain could be affected by several factors, such as sex, age, body mass index, breathing patterns, the intensity of the stimulation, and the affective state. Moreover, an association between the autonomic nervous system and the subjective experience of pain was found. Higher parasympathetic activity was associated with better self-regulation capacities and, accordingly, a higher pain inhibition capacity. Conclusions: HRV appears to be a helpful marker to evaluate nociceptive response in experimentally induced pain. Future studies are also needed in clinical samples to understand better the interindividual changes of autonomic response due to pain stimuli.

Prevalence of vitamin D deficiency among patients visiting a tertiary care centre

Background: Heart rate variability (HRV) as a measurement of autonomic function assumes great clinical importance. It is well known that particular patterns of body fat distribution increase coronary heart disease risk both in adults and children. While frank obesity is associated with reduced HRV, indicative of poorer autonomic nervous system (ANS) function, the association between body mass index (BMI) and HRV is less clear. The dynamic autonomic responses during exercise can be measured to give actionable information for training by analysis of the ECG to determine heart rate variability. While application of HRV has been applied to predict sudden cardiac death and diabetic neuropathy in assessing disease progression. The study revealed the changes in HRV in resting condition and also after a single bout of sub maximal treadmill exercise (50% of VO2 max.) among males and females in the age group of 17-25 years at rest, and the correlations between the HRV parameters at rest and after the exercise with BMI and WHR in the subjects. An observational cross sectional study was conducted in the Physiology Department of R.G.Kar Medical College, Kolkata, India on 60 subjects (n=60) of both sexes (30 males and 30 females) in the 17-25 years age, participated in this study. Their WHR and BMI were measured and HRV was recorded during rest and immediately after exercise by digital Polyrite. Result showed that the HRV of male were more than in female in resting condition. After submaximal exercise the HRV value of males were more than their respective resting HRV values though it was not significant and, in the females, post-exercise HRV was significantly more than their respective resting HRV. This study shows that females have higher parasympathetic activity than males. There is an association between WHR and BMI and HRV in healthy female persons, which shows that there is an increase in LF/HF(low frequency and high frequency) of values among males and females after a single bout of submaximal exercise though not significant in case of males but significant in case of females.

0110 Fluctuations Across the Menstrual Cycle in Cardiac Autonomic Activity During Sleep and Wake May Affect Memory Consolidation

Abstract Introduction Prior studies have shown that benefits of sleep for memory consolidation may be influenced by menstrual phase. Menstrual phase also impact autonomic regulation during sleep, and autonomic activity has been recently shown to play a role in sleep-dependent memory consolidation. Methods We investigated the interaction of menstrual cycle and autonomic activity measured by heart rate-variability (HRV) on sleep-dependent memory consolidation among 18-healthy females. Using a within-subjects design, we investigated episodic memory improvement with a nap paradigm during two phases of women’s menstrual cycle: 1) perimenses: −5 to +5 days from menses-onset, and 2) non-perimenses: window outside of perimenses. Subjects completed the memory test before (Test1) and after (Test2) a 90-minute polysomnographically (PSG)-recorded nap. We recorded sleep and HRV during 5-minutes of wake, and during the nap. Next, we compared sleep, HRV (RMSSD and HFnu), and memory performance between the two menstrual phases. Results Sleep architecture did not differ between perimenses and non-perimenses. Women performed similarly on the memory task at Test 1 (all ps&amp;gt;.061), but at Test 2, non-perimenses showed better performance (p = 0.02). Autonomically, perimenses had higher parasympathetic activity during wake (RMSSD-p = 0.04) and REM-sleep (HFnu-p = 0.04), compared with non-perimenses. Using bivariate correlations, we found positive associations between wake-HFnu and memory improvement (p = .02) during perimenses. In contrast, non-perimenses’ memory improvement was negatively correlated with wake-RMSSD (p &amp;lt;.001). In perimenses, memory improvement was also positively associtated with REM-HFnu (p = .04). No associations were found between autonomic sleep activity and memory in non-perimenses phase. Conclusion Our findings indicate a role for autonomic activity in memory improvement in both sleep and wake that is modulated by the menstrual cycle. HRV measures of parasympathetic activity were higher during perimenses phase in wake and REM-sleep. Interestingly, the HRV measures showed opposing relations with memory improvement based on the phase of the menstrual cycle. In sum, women’s cardiac autonomic activity fluctuates by menstrual phase and it is possible that these fluctuations affect the magnitude and direction of sleep-related memory consolidation. Support Sattari et al., 2017; Genzel et al., 2012; de Zambotti et al., 2013; Whitehurst et al., 2016.

Cardiovagal outflow impacts bronchial tone: ethnical/racial aspect

It is well documented that Africans have a prevalence of hypertension despite the high parasympathetic activity. The HRV analysis is a perspective noninvasive tool for the determination of ANS outflow. Till now it is not known if HF HRV power indicating cardiovagal outflow impacts bronchial tone. Orthostatic test is accompanied with a decrease of HF HRV power. The aim of the study was to evaluate if cardiovagal outflow impacts bronchial tone in sitting and upright position and whether this interaction may be associated with prevalence of hypertension in Africans.A total of 19 Caucasian, 17 African, 20 Arabic, and 22 Indian men were recruited from V.N. Karazin Kharkiv National University student population. No significant differences were in age, BMI and height of participants. In the sitting and upright positions ECG, tidal volume (TV), and respiratory rate was continuously recorded, LF and HF HRV power in absolute units and minute ventilation (MV) were computed with CardioLab CS and SPIROCOM pc based systems (XAIMedica, Ukraine). The sitting position was taken as a baseline according to requirements of the spirometry system. The SBP and DBP were recorded my means automatic digital sphygmomanometer (Nissei WS‐1011, Japan) at 4.5 minute of each 5 min stage. Two‐way repeated measures MANOVA with Bonferroni correction was used to test for effects of orthostasis and ethnicity/race on cardiovascular, respiratory, and HRV variables, multiple regression analysis was used to determine predictors of MV. All analyses were conducted using SPSS 22. Written informed consent was obtained from all participants.The highest values of LnHF were observed in Africans, the significant difference was between them and Indians at rest indicating high parasympathetic activity in Africans in congruence with previous reports (Fig. 1). Upon assuming the upright position LnHF power was significantly reduced in all the groups showing decreased cardiovagal outflow necessary to keep blood pressure and brain perfusion at normal level. Upon standing the LnLF power was reduced only in Africans. In accordance with our hypothesis, decrease of LnLF, possibly indicating decrease of inhibitory influence on sympathetic nervous system, in Africans, represented one more mechanism opposing effect of gravity and providing normal perfusion of tissues in standing position.The MV was significantly lower in Africans than in Arabs and Indians and TV was less in Africans compared with Caucasians and Arabs in both positions (Fig. 2). Our data from multiple regression analysis revealed that MV in sitting and standing positions was negatively associated with LnHF HRV power indicating that parasympathetic outflow to bronchial smooth muscle works in parallel with cardiovagal outflow. The orthostatic stress did not modulate this autonomic‐respiratory interaction.In conclusion, it is suggested that parasympathetic outflow impacts simultaneously bronchial tone and cardiovascular system. High parasympathetic activity in Africans reduced significantly tidal volume and minute ventilation and might cause activation of chemoreflex and explain increased blood pressure in this group.Effect of ethnicity/race and orthostasis on LnLF HRV power (A) and LnHF HRV power (B) in young men. *P&lt;0.05, *** P&lt;0.001. Data are expressed as means±SE.Figure 1Effect of ethnicity/race and orthostasis on minute ventilation (A) and tidal volume (B) in young men. *P&lt;0.05, ** P&lt;0.01. Data are expressed as means±SE.Figure 2

Soccer Matches but Not Training Sessions Disturb Cardiac-Autonomic Regulation During National Soccer Team Training Camps

ABSTRACT Purpose: Heart rate variability (HRV) can be used to monitor changes in autonomic nervous system (ANS) function. Monitoring HRV via the natural log of the root-mean-square difference of successive normal RR intervals (lnRMSSD), a decrease was related to lower parasympathetic activity and a fatigued state, and an increase was related to higher parasympathetic activity and better physical conditioning. This study analyzed daily ANS function changes among professional soccer players at national team training camps during preparation for the UEFA Eurocup 2016. Method: 23 professional soccer players were distributed into two groups: First eleven (players who played more than 60 minutes per soccer match) and Reserves (the rest of the players). HRV and session training load (s-TL) were monitored. Between-group daily differences were assessed using two-way mixed repeated measures ANOVA. Results: s-TL significantly increased (p < .05) at the beginning of each camp and significantly decreased the day before the soccer match (p < .001). There was a significant time by group interaction in lnRMSSD (p = .024). Changes were found in the First eleven group from match day +1 to match day +2 (+0.523 ms, p = .003). After the soccer match, there were between-group differences (p < .05) at +24h and +72h in lnRMSSD. Conclusions: During national team training camps, ANS function was only modified 24h and 72h after playing soccer matches, in players who played a minimum of 60 minutes. This knowledge can help coaches to monitor the impact of soccer matches during training camps to detect fatigue and improve recovery.

High parasympathetic activity as reflected by deceleration capacity predicts atrial fibrillation recurrence after repeated catheter ablation procedure.

High parasympathetic nervous system (PNS) activity is accurately reflected by deceleration capacity (DC) and is involved in atrial fibrillation (AF) recurrence after catheter ablation procedure. When compared with initial catheter ablation procedure, repeated procedures for AF recurrence are followed by a lower success rates, estimated at 50%. Our objective was to evaluate the impact of PNS activity assessed by DC measured before repeated procedure on AF recurrence after repeated procedure. Consecutive patients who underwent an initial catheter ablation procedure for pulmonary vein (PV) isolation and a repeated catheter ablation procedure for AF recurrence were selected. Additional 24-h ambulatory electrocardiographic recording between procedures for DC measurement was required for inclusion. A total of 110 patients were included. Seventy-two patients underwent cryoballoon (CB) ablation and 38 patients underwent radiofrequency (RF) ablation as initial procedure, while all patients underwent RF ablation as repeated procedure. DC was higher in cases with right-sided PV reconnection (p = 0.04, OR = 1.38, 95% CI = 1.08-1.78). In patients with CB ablation as initial procedure, DC was higher in patients with PV reconnection (p = 0.03, OR = 1.29, 95% CI = 1.11-1.70), and the number of reconnected PVs was higher in patients with DC ≥ 7.0ms (median DC value used for dichotomization, p = 0.02, OR = 2.19, 95% CI = 1.10-4.37). In multivariate Cox regression, DC predicted AF recurrence after repeated ablation (p = 0.004, HR = 1.68, 95% CI = 1.35-1.82). In multivariate binary regression, DC predicted persistent AF type recurrence after repeated ablation (p = 0.01, OR = 1.50, 95% CI = 1.10-2.02). DC is a novel predictor of AF recurrence and AF recurrence type after repeated catheter ablation procedure. DC may reflect the need of more intensive treatment strategies in patients with high PNS activity.

Analyzing the Efficacy and Design Considerations of VR Environments to Manage Anxiety & Depression in AYA Cancer Patients

Prior studies have reported that adolescent and young adult (AYA) patients are specifically vulnerable to distress because of the intersection of disease and age. Compared to older cancer patients, AYA cancer patients indicate a more negative psychosocial outcome. Recent studies have focused on improving the quality of life of AYA patients by providing adjunctive non-pharmacological interventions. Popular methods adopted include cognitive behavioral therapy, hypnosis, video games and virtual reality (VR) exposure. Although VR has been tested among other cancer populations, to our knowledge, no studies have focused on the efficacy of VR for mitigating mental distress in the AYA population. Additionally, no studies have focused on what specific virtual-based experiences are efficacious without causing cybersickness in cancer patients. Research has found that up to 25% of healthy patients exposed to VR experience some form of cybersickness. This longitudinal study analyzed the efficacy of VR in the AYA population and sought to understand their preferences in virtual environments. The study included eight AYA cancer patients admitted to our institution receiving inpatient chemotherapy. Seven patients had acute leukemia and the 8th patient had medulloblastoma. Patients were offered the VR intervention every other day during the hospital stay. On average, patients were enlisted in the study for 19 days, and were provided with 27 different virtual environments to choose from. Subject scores were collected using validated survey instruments, including the Numeric Rating Scale (NRS) for pain, State Trait Anxiety Inventory (STAI) for anxiety, and Hospital Anxiety and Depression Scale (HADS-D) for depression. Objective measures were also collected including heart rate and electrodermal response. Additional qualitative data were collected via patient interviews to better understand the patient's attitudes and behaviors regarding their virtual reality experience. Responses collected from patients using HADS-D, STAI showed that, on average, there was a 15% decrease in depression and 13% decrease in general anxiety after receiving the VR intervention. Additionally, the response from the NRS showed that their perception of pain decreased by 18%. Moreover, these results were supported by the objective measures, where the frequency domain metric of heart rate variability, LF/HF (Low frequency to High Frequency power) ratio decreased by 42% displaying a high parasympathetic nervous system activity during the intervention and decrease in the number of bursts in skin conductance response by 7%. It was also observed from the survey that AYA patients preferred environments with more interaction and presence rather than simply exploring. Although no participants reported significant cybersickness, it was observed that 50% of the population reported fatigue at least once during the period of study. Hence, the design consideration of the VR environment is a crucial factor, especially while providing intervention for cancer patients. This proof of concept study affirms the capability of VR to be used as an adjunct therapy to help manage pain, anxiety and depression in AYA patients and provides design consideration for VR environments to be used in AYAs. Future work includes the development and testing of adaptive environments using affective computing techniques where the virtual environment changes according to the patient's mood. Disclosures Cull: Celgene: Speakers Bureau; ADC Therapeutics: Research Funding.

Understanding mind-body disciplines: A pilot study of paced breathing and dynamic muscle contraction on autonomic nervous system reactivity.

Mind-body disciplines such as yoga, Tai Chi, and Qigong have been demonstrated to activate the parasympathetic nervous system, but it remains unclear how these practices achieve these results, whether by breathing, movement, or some combination. This pilot study establishes a model to examine the individual and combined effects of paced breathing and rhythmic skeletal muscle contraction on the activation of the parasympathetic system during a cognitive stressor. Male participants were randomly assigned to one of four preconditioning groups: (a) paced breathing alone, (b) alternating upper extremity muscle contractions, (c) paced breathing synchronized with alternating contractions, or (d) a neutral control task. Autonomic response was assessed by heart rate variability during a standardized cognitive stressor. The alternating contraction group had 71.7% higher activation of parasympathetic signal over respiration alone (p < .001). Alternating contractions synchronized with breathing demonstrated 150% higher parasympathetic activation than control (p < .0001). Comparing the contraction alone and synchronized groups, the synchronized group demonstrated 45.9% higher parasympathetic response during a cognitive stressor (p < .001). In conclusion, paced breathing synchronized with rhythmic muscle contraction leads to more resilient activation of the parasympathetic response than either alternating contractions or breathing alone, which may help explain the stress reducing benefits of mind-body disciplines.