Parasympathetic Nervous Activity Research Articles

The Effects of Slow Breathing during Inter-Set Recovery on Power Performance in the Barbell Back Squat

Slow breathing (SB) reduces sympathetic nervous system activity, the heart rate (HR), and blood pressure (BP) and increases parasympathetic nervous system activity, HR variability, and oxygen saturation which may lead to quicker recovery between bouts of exercise. Therefore, the purpose of this study was to examine whether a SB technique using the 4-7-8 method between sets of barbell back squats (SQs) would attenuate drops in power and bar velocity. In a randomized, crossover design, 18 healthy resistance-trained college-aged males (age: 20.7 ± 1.4 years, body height: 178.6 ± 6.4 cm, body mass: 82.2 ± 15.0 kg, 4.5 ± 2.4 years of experience) performed 5 sets of 3 repetitions of SQs with normal breathing (CON) or SB during the 3-min recovery between sets. Peak and average power and bar velocity were assessed using a linear positioning transducer. HR recovery (RHR), systolic BP recovery (RBP), the rating of perceived exertion (RPE) and the rating of perceived recovery score (RS) were assessed after each set. There were no significant differences between conditions for peak and average power and bar velocity, RBP, RPE, and RS (p > 0.211). SB led to a greater RHR after set 2 (SB: 51.0 ± 14.9 bpm vs. CON: 44.5 ± 11.5 bpm, p = 0.025) and 3 (SB: 48.3 ± 13.5 bpm vs. CON: 37.7 ± 11.7 bpm, p = 0.006) compared to the CON condition. SB was well tolerated, did not hinder nor improve training performance and improved RHR after the middle sets of SQs. Further investigations are warranted to examine the effects of other SB techniques and to determine SB’s effects on different training stimuli as well as its effects over an entire workout and post-workout recovery metrics.

Effect of olfactory stimulation from aromatherapy on the autonomic nervous activity during aerobic exercises

Variations in the autonomic nervous system activity during exercise therapy in patients with cardiovascular diseases may lead to adverse events. Aromatherapy may reduce these adverse events by enhancing parasympathetic nervous activity (PNA). However, the effects of aromatherapy during exercise remain relatively unknown. This study aimed to evaluate the effect of aromatherapy on autonomic nervous activity during exercise and recovery. This randomized crossover study included 20 healthy men subjected to both aroma and placebo conditions which involved rest and moderate-intensity aerobic exercise on a cycle ergometer, followed by recovery. Blood pressure, heart rate variability indices, and SpO2 were measured during the rest, exercise, and recovery phases. Moreover, aroma preferences and emotional changes in response to the aroma were assessed. Under the placebo condition, high frequency (HF), root mean square of successive differences indices, and heart rate showed delayed recovery (P < 0.05). Furthermore, a moderate positive correlation was identified between aroma preference, pleasant emotions induced by aromatherapy, and the HF index (P < 0.05). These results indicate that aromatherapy facilitates the recovery of PNA after exercise. Furthermore, these effects were more pronounced among individuals who exhibited a stronger preference for and more positive emotions toward aromas.

Does Parasympathetic Nervous System Activity Exacerbate Depressive Symptoms in College Students Who Experienced Parent-Child Separation? A Longitudinal Examination.

Childhood separation caused by parental migration increases the risk of suffering depressive symptoms among college students. However, most studies in this field have focused on environmental factors and largely ignored the role of physiological reactivity to stress (e.g., parasympathetic nervous system activity) in this process. The present study examined the long-term effects of the parent-child separation experience on depressive symptoms in college students, and explored the moderating role of parasympathetic nervous system (PNS) activity in these relationships. The participants were 242 college students (Mage = 18.74 years, SD = 0.79; 32.2% male), including 149 college students who experienced parent-child separation and 93 college students without this experience. Using a three-wave longitudinal design, participants completed the measures of the parent-child separation experience, PNS activity (measured via respiratory sinus arrhythmia, RSA), and depressive symptoms at Time 1 (T1, before the COVID-19 lockdown). Their depressive symptoms were again measured at Time 2 (T2, during the COVID-19 lockdown) and Time 3 (T3, after the COVID-19 lockdown). The results showed that the parent-child separation experience positively predicted depressive symptoms in college students at three time points. Moreover, the parent-child separation experience positively predicted depressive symptoms at T2 among males with less and average RSA suppression but positively predicted depressive symptoms at T2 among females with greater RSA suppression. These findings indicate a long-term effect of parent-child separation on depressive symptoms in college students that still exist after they entered university, and that the effect varies depending on PNS activity and gender.

Partial Resistance to Thyroid Hormone-Induced Tachycardia and Cardiac Hypertrophy in Mice Lacking Thyroid Hormone Receptor β.

Background: Thyroid hormones regulate cardiac functions mainly through direct actions in the heart and by binding to the thyroid hormone receptor (TR) isoforms α1 and β. While the role of the most abundantly expressed isoform, TRα1, is widely studied and well characterized, the role of TRβ in regulating heart functions is still poorly understood, primarily due to the accompanying elevation of circulating thyroid hormone in TRβ knockout mice (TRβ-KO). However, their hyperthyroidism is ameliorated at thermoneutrality, which allows studying the role of TRβ without this confounding factor. Methods: Here, we noninvasively monitored heart rate in TRβ-KO mice over several days using radiotelemetry at different housing temperatures (22°C and 30°C) and upon 3,3',5-triiodothyronine (T3) administration in comparison to wild-type animals. Results: TRβ-KO mice displayed normal average heart rate at both 22°C and 30°C with only minor changes in heart rate frequency distribution, which was confirmed by independent electrocardiogram recordings in freely-moving conscious mice. Parasympathetic nerve activity was, however, impaired in TRβ-KO mice at 22°C, and only partly rescued at 30°C. As expected, oral treatment with pharmacological doses of T3 at 30°C led to tachycardia in wild-types, accompanied by broader heart rate frequency distribution and increased heart weight. The TRβ-KO mice, in contrast, showed blunted tachycardia, as well as resistance to changes in heart rate frequency distribution and heart weight. At the molecular level, these observations were paralleled by a blunted cardiac mRNA induction of several important genes, including the pacemaker channels Hcn2 and Hcn4, as well as Kcna7. Conclusions: The phenotyping of TRβ-KO mice conducted at thermoneutrality allows novel insights on the role of TRβ in cardiac functions in the absence of the usual confounding hyperthyroidism. Even though TRβ is expressed at lower levels than TRα1 in the heart, our findings demonstrate an important role for this isoform in the cardiac response to thyroid hormones.

Compassion training influences heart-rate variability within severe depression

BackgroundHeart-rate variability (HRV) is a marker of parasympathetic nervous system activity, and is a robust predictor of improved mental and physical health. Current psychotherapeutic interventions are effective at reducing self-report depressive symptoms, but few have improved HRV within a sample of severe depressive symptomatology. MethodThis study explores the impact of a brief Compassion Focused Therapy exercise (CFT) on HRV response. ResultsResults indicate that a brief CFT exercise can successfully target depressive physiology via increasing HRV, at two distinct timepoints, pre- and post- a two-week self-directed training period, even when controlling for respiration. Specifically, we first show that CFT can significantly increase HRV. Second, we show that CFT exercise can increase a subset of participants’ HRV level above a clinical cut-off value of low resting-HRV. Third, we describe how participant engagement with the CFT audio during the two-week training was very low, with 50% of individuals not accessing the audio during this period. Finally, during the CFT practice at post-two-week training, HRV was shown to decrease across time, potentially indicating a greater participant engagement in the ‘threat’ component of the exercise. LimitationsAlmost 50% of the sample did not listen to the CFT exercise during the two-week training period, a feature that has implications for self-directed delivery of experimental and treatment interventions. ConclusionsCFT can significantly improve HRV for those with severely depressed symptoms at the state-level, and future work should continue to examine CFT's effectiveness for those with depression.

Evaluating the indicators ofaheart rate variability analysis indogs using Poincaré plots.

Heart rate variability analyses using Poincaré plots can beuseful for evaluating the autonomic nervous system function. However, the interpretation ofthe quantitative indicators ofPoincaré plots remains controversial. Thus, few studies have verified the effectiveness ofthe quantitative indicators inveterinary medicine. This study aimed toverify the reliability ofPoincaré plot indicators using pharmacological models indogs. Four healthy beagles were used inthis study. Each dog was treated with propranolol, atropine, and propranolol-atropine toblock the sympathetic, parasympathetic, and sympathetic-parasympathetic functions, respectively. The quantitative indicators ofthe Poincaré plots were calculated based ondata from 300electrocardiogram beats collected before and after the administration ofeach drug and statistically analysed. The quantitative indicators ofthe Poincaré plots, such asthe standard deviation perpendicular tothe major axis (SD1), standard deviation along the major axis (SD2), and SD1×SD2, significantly decreased after the drug administration inboth the parasympathetic and sympathetic-parasympathetic blockade models. However, nosignificant differences were observed inSD1/SD2 between the groups. The Poincaré plots reflected the changes inthe autonomic nervous system ofdogs. Indogs, SD1, SD2, and SD1×SD2 can detect astate inwhich parasympathetic nerve activity issuppressed.

Use of Atrial Fibrillation Electrograms and T1/T2 Magnetic Resonance Imaging to Define the Progressive Nature of Molecular and Structural Remodeling: A New Paradigm Underlying the Emergence of Persistent Atrial Fibrillation.

The temporal progression states of the molecular and structural substrate in atrial fibrillation (AF) are not well understood. We hypothesized that these can be detected by AF electrograms and magnetic resonance imaging parametric mapping. AF was induced in 43 dogs (25-35 kg, ≥1 year) by rapid atrial pacing (RAP) (3-33 weeks, 600 beats/min), and 4 controls were used. We performed high-resolution epicardial mapping (UnEmap, 6 atrial regions, both atria, 130 electrodes, distance 2.5 mm) and analyzed electrogram cycle length, dominant frequency, organization index, and peak-to-peak bipolar voltage. Implantable telemetry recordings were used to quantify parasympathetic nerve activity over RAP time. Magnetic resonance imaging native T1, postcontrast T1, T2 mapping, and extracellular volume fraction were assessed (1.5T, Siemens) at baseline and AF. In explanted atrial tissue, DNA oxidative damage (8-hydroxy-2'-deoxyguanosine staining) and percentage of fibrofatty tissue were quantified. Cycle length and organization index decreased (R=0.5, P<0.05; and R=0.5, P<0.05; respectively), and dominant frequency increased (R=0.3, P n.s.) until 80 days of RAP but not thereafter. In contrast, voltage continued to decrease throughout the duration of RAP (R=0.6, P<0.05). Parasympathetic nerve activity increased following RAP and plateaued at 80 days. Magnetic resonance imaging native T1 and T2 times increased with RAP days (R=0.5, P<0.05; R=0.6, P<0.05) in the posterior left atrium throughout RAP. Increased RAP days correlated with increasing 8-hydroxy-2'-deoxyguanosine levels and with fibrosis percentage (R=0.5, P<0.05 for both). A combination of AF electrogram characteristics and T1/T2 magnetic resonance imaging can detect early-stage AF remodeling (autonomic remodeling, oxidative stress) and advanced AF remodeling due to oxidative stress and fibrosis.

Plank exercise improves respiratory capacity through positive changes in body composition, abdominis function, and autonomic nerves' activities

AbstractThis research aimed to explore the impact of plank exercise training (PET) on respiratory function, body composition, abdominis performance, and autonomic nervous system (ANS). Sixty‐one young adults participated and were divided into a control group (CG, n = 31) and an exercise group (EG, n = 30), wherein PET was administered 3 days per week for 12 weeks. After the experiment, the body composition of the CG deteriorated, whereas that of the EG improved (p &lt; 0.001). The EG exhibited a reduction of ∼34% in the mean maximum displacement and a rise of ∼20% in the mean contraction time of the abdominis. The sit‐up in the EG demonstrated a significant increase of ∼55%. In the EG, there was a substantial increase in peak expiratory force by ∼24% and forced expiratory volume in 1 s by ∼14%, accompanied by a reduction in resting respiratory rate by ∼ −9%. When compared to the CG, these alterations were significant between the two groups (p = 0.001). In the EG, there was a significant decrease in resting heart rate by ∼2%, accompanied by a decrease in sympathetic nervous activity by ∼ −5% and by an increase in parasympathetic nervous activity by ∼5%. When compared to the CG, these alterations were significant between the two groups (p = 0.001). The findings of this study revealed that implementing PET in young adults, while controlling for dietary intake and physical activity, resulted in noteworthy changes in respiratory capacity. These changes were coupled with improvements in body composition, abdominal functions, and the ANS.

Effects of war-related stress on the cardiovascular system, metabolism and the rate of ageing in women

Chronic war-related stress (WRS) due to disruption of adaptation mechanisms can affect physiological processes in the body, in particular, metabolism, neuroendocrine regulation, and the state of the cardiovascular and respiratory systems. WRS can also cause changes in the body's rate of ageing. Purpose of the Study: To investigate the effects of WRS on the cardiovascular system, metabolism and the rate of ageing in women. The study included 91 women aged from 30 to 74 years who experienced chronic WRS and 79 women examined before the Russian-Ukrainian war (control group). The biological age (BA) was determined according to the indicators of hemodynamics, heart rate variability and metabolism (cardiometabolic age) using a formula that was obtained by multiple stepwise regression. The indicators were selected, which correlate as much as possible with age and little among themselves. During the war, no statistically significant changes in heart rate, or systolic and diastolic blood pressure were observed, but a significant reduction in overall HRV in the supine position was obtained. Additionally, indices of parasympathetic nervous system activity are significantly lower during the war. In women, examined during the war, there is a statistically significant higher concentration of blood plasma glucose at fasting and 2-hour post-standard oral glucose tolerance test, they also exhibit higher plasma insulin concentration and a higher HOMA-IR index. An increased frequency of prediabetic disorders was observed. So, in the group of women examined before the war, an elevated fasting blood plasma glucose level was found in 6 %, while during the war it was observed in 19 %. Impaired glucose tolerance before the war was present in 10 % of women, and during the war, it increased to 25 %. To assess the effect of WRS on the rate of ageing, the BA of women before and during war was calculated. The formula for calculating BA was obtained on a group of healthy women before the war, and the ageing rate was calculated as the difference between BA and chronological age (CA). The average BA in the group of women before the war was 56.5±1.4 years, and in the group during the war – 64.7 ± 1.1 years. The difference between BA and CA is (0.02 ± 0.79) years in the women before the war and (10.8 ± 1.36) years during the war (p &lt; 0.05). Chronic WRS leads to the disruption of the cardiovascular system's functioning and simultaneously triggers an imbalance in the autonomic nervous control in women. These changes indicate a state of heightened stress. Women exposed to chronic WRS experience unfavourable alterations in carbohydrate and lipid metabolism, increasing the risk of diabetes mellitus development. Chronic WRS accelerates the rate of cardiometabolic ageing in women. _________________________________________________________________________________________ Keywords: cardiovascular system; metabolism; biological age; war-related stress; woman

Depression is associated with discoordination between heart rate variability and physical acceleration in older women.

It is well known that depression is closely associated with the autonomic nervous system and physical acceleration (PA), which may cause functional time-deviance between these two parameters. Exploring this relationship is important in sustaining the mental and physical health of older adults in daily life. However, few studies have assessed the relationship between depression and the coordination of parasympathetic nervous activity (PSNA) and PA. The present study was designed to investigate whether the coordination between PSNA and PA is associated with the mental state of healthy volunteers in normal daily lives and the underlying mechanism. In total, 95 adult women were divided into non-older and older groups comprising 50 (aged 20-59 years) and 45 (aged 60-85 years) women, respectively. PSNA and PA data were simultaneously obtained every minute for 24 h during the free-moving day using the ActiveTracer accelerometer. Lag time was determined as the time difference between PSNA and PA, and it was introduced as a parameter of %lag0, which is the percent ratio of the lag = 0 min between PSNA and PA in 1 h. The General Health Questionnaire 28 (GHQ28) was used to evaluate the effects of psychological distress, including depression. In the hour before sleep, %lag0 was significantly lower in older women (38.7 ± 6.4) who had higher GHQ28 values (subscale D = 0, n = 12) compared with that in older women (19.4 ± 10.5) with lower values (subscale D ≧ 1, n = 33) (p < 0.05). Impairments in coordination between PSNA and PA are significantly associated with depression in older women, particularly in the hour before sleep on free-moving days.

Choroidal Thickness Increases During Parasympathetic Dominance After Immersion of the Foot in Warm Water.

This study aimed to assess the course of changes in choroidal morphology after immersion of the foot in warm water at 40°C using enhanced depth imaging optical coherence tomography (EDI-OCT). Forty-three right eyes of 43 healthy participants were included. Changes in choroidal morphology were determined using EDI-OCT to evaluate subfoveal choroidal thickness (SCT). Systolic, diastolic, and mean blood pressures (SBP, DBP, and MBP, respectively) were also measured to determine systemic circulatory dynamics at baseline, immediately after immersion (0 min), and 10, 20, and 30 min after immersion. Immediately after immersion, SBP, DBP, and MBP were significantly declined versus baseline. In contrast, the SCT was significantly increased after warm water immersion. However, all these parameters did not change significantly compared to the baseline within 30 min. In the normal eye, parasympathetic nerve activity induced by warming stimuli increases choroidal morphology in response to a decrease in systemic circulatory activity, which normalizes within 30 min. The findings of this study may provide basic data for the prevention and treatment of various choroidal diseases in which sympathetic hyperactivity is involved in the pathogenesis.

Effects of three-week intake of Matcha green tea powder on heart rate variability metrics

Introduction: Compared to other green teas, higher intake of multiple phytochemicals is achieved with Matcha green tea consumption. Green tea consumption is known to have metabolic effects but is also consumed for supposed calming effects. The aim of the present study was to examine the effects of encapsulated Matcha green tea on heart rate variability metrics during supine rest, as well as on physiological and metabolic responses during both supine rest and moderate-intensity exercise. Methods: Healthy females (n=8, age: 22±3 yrs, body mass: 68±11 kg, height: 162±5 cm) volunteered. The study employed a placebo-controlled, randomised cross-over design. Time-domain heart rate variability metrics during supine rest (n=5) and physiological and metabolic responses using indirect calorimetry techniques during supine rest and 60-min of moderate-intensity (~ 4-METs) treadmill walking (speed: 4.4±0.5 km·h-1) were measured following 3 weeks of 3 g·day-1 of Matcha green tea or placebo. Results: During supine rest with Matcha green tea, all participants had lower heart rates by 13±7% (P=0.01, d= -1.45), higher mean beat-to-beat RR intervals by 16±9% (P=0.03, d=1.25), higher SDNN by 44±32% (P=0.01, d=0.76) and higher pNN50 by 139±139% (P&lt;0.01, d=1.28). Matcha green tea had no effects on the physiological and metabolic responses during supine rest and moderate-intensity treadmill walking (e.g. respiratory exchange ratio, placebo: 0.78±0.04; Matcha: 0.78±0.03, P=0.87). Fat oxidation during supine rest was correlated (r=0.75, P&lt;0.01) with the moderate-intensity walking induced fat oxidation. Conclusions: In young adult healthy females, Matcha green tea beneficially effects heart rate variability metrics during supine rest indicating an alteration in parasympathetic nervous activity and therefore suggestive of a relaxing effect. Matcha green tea did not change the metabolic responses during supine rest and exercise possibly due to the low respiratory exchange ratio in the female cohort. Future work should address the effectiveness of Matcha green tea during conditions of psychological stress.Keywords: Matcha green tea, heart rate variability, rest, walking, substrate oxidation

The relationship between sustained attention and parasympathetic functioning

Sustained attention (SA) is an important cognitive ability that plays a crucial role in successful cognitive control. Resting vagally-mediated heart rate variability (vmHRV) has emerged as an informative index of parasympathetic nervous system activity and a sensitive correlate of individual differences in cognitive control. However, it is unclear how resting vmHRV is associated with individual differences in sustained attention. The primary aim of the current study was to assess if resting vmHRV was associated with individual differences in performance on a neuropsychological assessment of sustained attention. We further aimed to characterize the relationship between resting vmHRV and dispositional factors related to sustained attention, specifically attentional errors in daily life, self-regulation, mindfulness and media-multitasking. Based on previous work, we hypothesized higher resting vmHRV would be associated with better sustained attention across task-based and self-report measures. We did not find resting vmHRV to be significantly associated with performance measures on a task-based assessment of sustained attention. Further, resting vmHRV was not significantly associated with attention errors, self-regulation, mindfulness, or media-multitasking. This work stands to expand the current understanding between parasympathetic functioning, cognition, and behavior, investigating the unexplored domain of sustained attention and related dispositional factors.

A PEDF peptide mimetic effectively relieves dry eye in a diabetic murine model by restoring corneal nerve, barrier, and lacrimal gland function

PurposeThe study investigated effectiveness of a novel PEDF peptide mimetic to alleviate dry eye-like pathologies in a Type I diabetic mouse model established using streptozotocin. MethodsMice were treated topically for 3–6 weeks with Ppx (a 17-mer PEDF mimetic) 2x/day or vehicle. Corneal sensitivity, tear film, epithelial and endothelial injury were measured using Cochet-Bonnet esthesiometer, phenol red cotton thread wetting, fluorescein sodium staining, and ZO1 expression, respectively. Inflammatory and parasympathetic nerve markers and activation of the MAPK/JNK pathways in the lacrimal glands were measured. ResultsDiabetic mice exhibited features of dry eye including reduced corneal sensation and tear secretion and increased corneal epithelium injury, nerve degeneration, and edema. Ppx reversed these pathologies and restored ZO1 expression and morphological integrity of the endothelium. Upregulation of IL-1β and TNFα, increased activation of P-38, JNK, and ERK, and higher levels of M3ACHR in diabetic lacrimal glands were also reversed by the peptide treatment. ConclusionThe study demonstrates that topical application of a synthetic PEDF mimetic effectively alleviates diabetes-induced dry eye by restoring corneal sensitivity, tear secretion, and endothelial barrier and lacrimal gland function. These findings have significant implications for the potential treatment of dry eye using a cost-effective and reproducible approach with minimal invasiveness and no obvious side effects.

The Interplay of Peer Victimization and Parasympathetic Nervous System Activity on Acute Inflammatory Stress Responses in Adolescence.

This study examined the extent to which adolescent peer victimization predicted acute inflammatory responses to stress, and whether both resting parasympathetic nervous system (PNS) activity and PNS stress reactivity moderated this association. 83 adolescents (Mage = 14.89, SDage = 0.52, 48% female) reported their history of peer victimization and were exposed to a standardized social stress task before and after which dried blood spot samples were collected to assay inflammatory markers. Inflammatory responses to the stress task were assessed with a latent inflammatory change factor using the cytokines interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α). PNS functioning, indexed by high-frequency heart rate variability, was measured at rest and during the stressor. Contrary to hypotheses, analyses revealed no direct relation between peer victimization and acute inflammatory responses, and resting PNS activity did not moderate this association. However, peer victimization predicted stronger inflammatory responses among adolescents with weaker PNS reactivity to the stress task (b = 0.63, p = .02). This association was not observed among adolescents with stronger PNS reactivity, for whom a negative but non-significant trend was found. Weaker PNS reactivity may thus indicate victimized adolescents' vulnerability for acute inflammatory responses, whereas stronger PNS reactivity may indicate adolescents' resilience to a social stressor.

PSVII-14 Reduction in Heart Rate Variability Parameters in Horses Treated with a Mixture of Lavender and Eucalyptus Essential Oil

Abstract Routine medical examinations can produce stress which can negatively impact the health and well-being of horses. Heart rate variability (HRV) is a non-invasive and inexpensive method to measure the balance between sympathetic and parasympathetic nervous system activity, which can help identify stress in horses. This study examined the effect of a combination of lavender and eucalyptus essential oil on stress responses in horses undergoing a routine medical exam. After a five-minute stall rest (baseline reading) data were collected in three, five-minute intervals (walk to and enter stock, medical exam, and recovery in stall). This study utilized a switch-back design where each horse (n = 10) received both treatments on different dates. The treatment groups received lavender (20%) and eucalyptus essential oil (5%) dissolved in petroleum jelly and virgin sunflower oil applied to inner nostrils. The control treatment consisted of only petroleum jelly and virgin sunflower oil applied to inner nostrils. The root mean square of the successive differences of heartbeats (RMSSD) was significantly reduced (P &amp;lt; 0.05) when horses were treated with essential oils while walking to stocks (51.7 ± 3.7), during the medical exam (50.5 ± 4.9), and during the recovery period (64.1.9 ± 5.7) compared with control treatment, to stocks (36.1 ± 4.4), the medical exam (39.0 .± 4.5), and during the recovery period (49.7 ± 5.5). The measured SD1 (parasympathetic) was significantly greater (P &amp;lt; 0.008) at walk to stocks in horses treated with essential oils (37.2 ± 1.9) compared with control treated (30.3 ± 3.1). The measured SD2 (sympathetic) was significantly less (P &amp;lt; 0.008) at walk to stocks in horses treated with essential oils (62.8 ± 1.9) compared with control treated (69.7 ± 6.8). The ratio of SD1/SD2 was significantly less (P &amp;lt; 0.008) at walk to stocks in horses treated with essential oils (1.7 ± 0.17) compared with control treated (2.4 ± 0.26). The high frequency percent (HF%) was also greater (P &amp;lt; 0.04) at walk to stocks in horses treated with essential oils (39.6 ± 4.9) compared with control treated (26.0 ± 4.1). The standard deviation of RR Interval (SDNN) values were increased (P &amp;lt; 0.03) in horses treated with essential oils during walking to stalks (50.8 ± 1.9), the medical exam (56.7 ± 5.0), and the recovery period (72.4 ± 12.9) compared with the control treatment, to stalks (44.5 ± 5.2), medical exam (44.0 ± 4.5), and during the recovery period (54.6 ± 6.2). The results of this study indicate that lavender and eucalyptus oil could be an effective means of reducing short-term stress in horses. The findings of this study can help develop more effective and humane management strategies for horses.

Effects of prenatal opioid exposure on infant sympathetic and parasympathetic nervous system activity.

Prenatal opioid exposure has been associated with developmental problems, including autonomic nervous system dysregulation. However, little is known about the effects of prenatal opioid exposure on the autonomic nervous system beyond the first days of life, particularly across both the parasympathetic and sympathetic branches, and when accounting for exposure to other substances. The present study examined the effects of prenatal exposure to opioid agonist therapy (OAT, e.g., methadone) and other opioids on infant autonomic nervous system activity at rest and in response to a social stressor (the Still-Face Paradigm) at six months among 86 infants varying in prenatal opioid and other substance exposure. Results indicated that OAT and other opioids have unique effects on the developing autonomic nervous system that may further depend on subtype (i.e., methadone versus buprenorphine) and timing in gestation. Results are discussed in the context of theoretical models of the developing stress response system.

PEP reward reactivity moderates the effects of RSA reactivity on antisocial behavior and substance use.

Integrating Polyvagal Theory and Reinforcement Sensitivity Theory (RST), we examined pre-ejection period (PEP) reward reactivity, which was suggested to index trait impulsivity, as a moderator between respiratory sinus arrhythmia (RSA) reactivity and antisocial behavior (ASB), and substance use in an urban male, adult sample. To understand the inconsistent findings between RSA reactivity and externalizing problems, we proposed to study both negatively and positively valenced tasks for RSA reactivity and to include PEP reward reactivity as a moderator for the RSA-behavior link. Data were collected from an urban sample of 131 male adults (active offenders, demographic controls, and college students). ICG (impedance cardiography) and ECG (electrocardiogram) were recorded, computing PEP (sympathetic nervous system activity marker) and RSA (parasympathetic nervous system activity marker), while participants completed the modified Trier Social Stress Test and a simple reward task. Reactivity was calculated by subtracting the baseline from the task activity. Consistent with prior studies, more RSA withdrawal to stress and less PEP shortening to reward predicted the most ASB and substance use. Less RSA withdrawal to reward and more PEP shortening to reward predicted the most ASB and substance use. We incorporated autonomic space, RST, and Polyvagal Theory to discuss our findings, and specifically highlight how clarifying what each reactivity captures based on the task demand (e.g., presence of social threat, need for vagal-mediated social affiliative behavior) can illuminate our understanding of the result patterns.

Effect on Satisfactory Seizure Control and Heart Rate Variability of Thread-Embedding Acupuncture for Drug-Resistant Epilepsy: A Patient-Assessor Blinded, Randomized Controlled Trial.

This randomized controlled trial investigates the efficacy of thread-embedding acupuncture (TEA) compared to sham TEA in treating drug-resistant epilepsy (DRE). Fifty-four DRE outpatients were randomly divided into two groups: TEA (27 patients) and sham TEA (27 patients). Both groups received four sessions of TEA or sham TEA, spaced four weeks apart, targeting GV20, GV14, BL15, BL18, ST40, and GB34 acupoints. Antiseizure medications were maintained at consistent doses throughout the study. Outcome measures included satisfactory seizure control, seizure freedom, and heart rate (HR) and heart rate variability (HRV) measurements. TEA demonstrated a significantly higher rate of satisfactory seizure control at follow-up compared to the sham TEA group (37% vs. 3.7%, p = 0.003). While no significant intergroup differences were observed in HR, HRV, and HRV components at each stage, the TEA group experienced a significant decrease in HR and a significant increase in HRV posttreatment. This study demonstrates TEA's effectiveness in managing DRE and suggests its impact may relate to heightened parasympathetic nerve activity. Further research with extended follow-up periods is necessary to validate these findings.

Pilot study shows skin-to-skin care with parents improves heart rate variability in preterm infants in the neonatal intensive care unit.

Skin-to-skin care in the newborn intensive care unit typically lasts for short periods of time and enhances breastfeeding, attachment, and parental self-esteem. Heart rate variability (HRV) increases with gestational age and is a measure of maturation of parasympathetic vs. sympathetic autonomic nervous system activity. HRV measurements may be useful in capturing changes in autonomic regulation in response to skin-to-skin care. To analyze the effects of skin-to-skin care on HRV in preterm infants receiving respiratory support. We hypothesized that skin-to-skin care would result in a more mature pattern of parasympathetic activity. In this prospective crossover study, infants <30 weeks' gestation and 1-6 weeks postnatal age had HRV recorded for 30 min before, during, and after skin-to-skin care sessions. HRV characteristics analyzed included the standard deviation of the normal-to-normal interval (SDNN), the root mean squared of successive differences of normal-to-normal intervals (RMSSD), and the standard deviation of decelerations (SDDec). 10 infants between 25 5/7-29 6/7 weeks gestational age and 7-41 days postnatal age completed 22 sessions while receiving respiratory support (positive pressure ventilation or nasal cannula oxygen). Two measures of HRV (SDNN and RMSSD) were significantly decreased by the end of the skin-to-skin sessions, compared to pre-session values. SDNN decreased from a median of 10.44 ms before the session to 6.70 ms after being placed back in bed (p < 0.05), with RMSSD decreasing from a median of 6.80 ms before the session to 4.32 ms while being held at the end of 30 min (p < 0.05). Skin-to-skin care with a parent resulted in a more mature autonomic nervous system pattern in preterm infants receiving respiratory support, suggesting physiologic benefit for the infant. No adverse events were seen during any session.