Sympathetic Nervous System Index Research Articles

Autonomic rehabilitation: Vagal and sympathetic impacts of modified occipitomastoid suture V-spread.

Autonomic rehabilitation using osteopathic manipulative treatment (OMT) to stimulate the vagus nerve may be a good adjunct therapy by physiatrists who treat dysautonomia. Heart rate variability (HRV) may provide quantitative evidence for the benefits of OMT on autonomic nervous system function. Elevated HRV indicates optimal health and reduced mortality risk, whereas low HRV is associated with stress, pain, and chronic disease pathology. To analyze the impact of modified occipitomastoid suture v-spread OMT technique on vagal tone by measuring HRV. Within-participant design with 5-minute HRV measurement pre- and post-OMT treatment. Clinical examination suites. Thirty healthy osteopathic medical students. A modified occipitomastoid suture v-spread treating somatic dysfunction by osteopathic physicians trained in osteopathic neuromusculoskeletal medicine. HRV variables related to vagal tone including root mean square of successive differences (RMSSD), percentage of successive normal sinus RR intervals >50 ms (pNN50), high frequency (HF), Parasympathetic Nervous System Index (PNSI), and Sympathetic Nervous System Index (SNSI). Repeated measures t-test analyzed the difference in mean HRV values after OMT. There were statistically significant increases in each of the HRV measures after OMT. Participants had a mean (95% confidence interval) RMSSD of 50.5 ms (38.3-62.8) at baseline and 55.0 ms (41.2-68.7, p = .013) post-OMT. pNN50 was 24.5% (17.6-31.3, n = 30) at baseline and 28.2% (20.8-35.6, p = .003) post-OMT. HF was 1549.6 ms2 (389.8-2709.4) at baseline and 1901.8 ms2 (618.2-3185.4, p = .103) post-OMT. PNSI was -0.1 (-0.5 to 0.2) at baseline and 0.1 (-0.3 to 1.5, p < .01) post-OMT, and SNSI was 0.2 (-0.1 to 0.6) at baseline and 0.05 (-0.3 to 0.4, p < .01) post-OMT. Normalization, due to high baseline variance, results include RMSSD 1.1 ms (1.0 to 1.1, p = .012), pNN50 1.3 (1.1 to 1.4, p = .011), and HF 1.2 ms2 (1.1 to 1.4, p = .018). Modified occipitomastoid suture v-spread may provide clinical benefit through increased vagal tone and decreased sympathetic activity.

Autonomic regulation in athletic horses repetitively participating in two novice jumping classes on consecutive days

IntroductionAnimal welfare is of great concern in equestrian sports and has been evaluated in athletic horses competing at different levels. However, the impact of consecutive days of jumping competition and the extent of resultant stress responses remains unclear. To address this point, the present study compared the changes in stress response via heart rate variability (HRV) in horses participating in two national jumping events on consecutive days.MethodsThe study involved six experienced horses equipped with heart rate monitoring devices. HRV variables were measured before, during, and after jumping at 10-min intervals for 60 min on each competition day.ResultsMultiple HRV variables decreased to varying degrees on both days from warm-up until 30 min post-jumping. Meanwhile, the mean heart rate increased during jumping and returned to normal levels at 50 min post-jumping on the first day (for all intervals, p &amp;lt; 0.05–0.001), while it remained elevated beyond 60 min post-jumping on the second day (for all intervals, p &amp;lt; 0.01–0.001). Additionally, maximum heart rate and respiratory rate were higher on the second day than in the first round during the warm-up phase (p &amp;lt; 0.05 for both variables). The proportion of the HRV low-frequency band was higher during riding on the second day (p &amp;lt; 0.05), while the proportion of the high-frequency band was reduced during warm-up on the first day (p &amp;lt; 0.05) and during course riding on the second (p &amp;lt; 0.01). Meanwhile, the sympathetic nervous system index took longer to return to baseline on the second day than on the first.DiscussionThese results suggest that autonomic regulation differed in horses between jumping rounds on two consecutive days, with horses experiencing higher sympathetic activity and potentially increased stress in the second round. This information is important for riders, highlighting the need to be mindful of potential stress that could, at least in part, impact the welfare of horses participating in the same jumping competition on consecutive days.

Cologne ergonomic measurement for robotic surgery (CEMRobSurg) using the Hugo™ RAS System.

The ergonomic advantages and potential challenges that robotic surgery poses to the well-being of surgeons are mainly unexplored. The most recent surgical robot introduced on the European market is the Hugo™ RAS System by Medtronic. This study aims to evaluate the ergonomic benefits of the Hugo™ RAS System, which is available in our training laboratory, CeMIT (Center for Medical Innovation and Technology Cologne). Using the previously established Cologne Ergonomic Measurement Setup for Robotic Surgery (CEMRobSurg), we measured three parameters related to ergonomic posture from subjects with different levels of surgical expertise (laypeople, medical students, surgical residents, and expert robotic surgeons). The heart rate was measured continuously using a polar band. The noise level was measured while using the Hugo™ RAS System, and automated photographs using our locally developed methodology were captured of the participant every 2s to assess body posture. The ergonomic measurements were conducted while the subject performed the same standardized robotic training exercises (Peg Board, Rope Walk, and Ring Walk). A total of 53 participants were enrolled in this study. The average noise level during all measurements was 54.87 dB. The highest stress level was measured in surgical residents with a sympathetic nervous system index (SNS index) of 1.15 (min - 1.43, max 3.56). The lowest stress level was measured in robotic experts with an SNS index of 0.23 (min - 0.18, max 0.91). We observed a risk-prone positioning of the neck and elbow in medical students (mean 39.6° and 129.48°, respectively). Robotic experts showed a risk positioning in the knee and hip region (mean 107.89° and 90.31°, respectively). This is the first study to analyze and objectify the ergonomic posture of medical students, surgical trainees, surgeons, and laypeople using the open console, modular Hugo™ RAS System. Our findings offer recommendations for operating surgeons and allow for a comparative analysis between the different robotic systems. Further evaluations in real-time operative scenarios will follow.

Comparison of daily heart rate and heart rate variability in trained and sedentary aged horses

Athletic horses are usually retired from equestrian competition at an advanced age. Aged horses may then continue to have regular exercise or are sedentary. The comparison of autonomic regulation between sedentary aged horses (SAH) and trained aged horses (TAH) after retirement remains unpublished. This study compared daily heart rate (HR) and heart rate variability between 11 SAH and 11 TAH over 22 h (07.00 h to 05.00 h on an alternate day) and during the day and night. An increase in mean beat-to-beat (RR) intervals (p < 0.01-0.0001) and parasympathetic nervous system (PNS) index (p < 0.05-0.0001), corresponding to the decreased HR and sympathetic nervous system (SNS) index (p < 0.01-0.0001), was observed at night. Compared to SAH, lowered mean HR and SNS index, corresponding to elevated mean RR intervals and very-low-frequency bands, were marked in TAH during the day (p < 0.05 for all variables). Whereas the standard deviation of the RR intervals index was higher in TAH than in SAH during the day and night (p < 0.05 for both periods). It was suggested that aged horses with different physical activities revealed distinct autonomic responses. TAH demonstrated higher HRV than SAH during the day. A decreased HR in TAH is prone to result from a reduced SNS role, leading to a shift toward more PNS activity during the day. More research is warranted to determine to what extent the autonomic regulation is modulated by accompanying higher exercise volume or programmed exercise in aged horses.

Impact of different cooling solutions on autonomic modulation in horses in a novice endurance ride

Cooling down is essential for horse recovery before veterinary inspection during an endurance ride. As salt potentially decreases water temperature, we tested whether adding salt to the water used to cool horses could aid their recovery. Twelve healthy Arabian horses participating in a novice endurance ride were divided evenly into two groups. Heart rate variability (HRV) variables, including time and frequency domains, non-linear results, and autonomic nervous system indices, were determined before recovery and at 1-min intervals for 9 min during recovery using either cold or cold-saline water. An interaction between water type and time was observed in the modulation of the SD of beat-to-beat (RR) intervals, square root of the mean squared differences between successive RR intervals (RMSSD), HRV triangular index, very low-frequency band (VLF), low-frequency band/high-frequency band ratio, and SD of the Poincaré plot perpendicular to the line of identity (SD1) non-linear results. A decrease in heart rate and the sympathetic nervous system index corresponding to an increase in RR intervals and the parasympathetic nervous system (PNS) index was observed over time. A rise in the triangular interpolation of the normal-to-normal intervals, number of successive RR interval pairs that differ more than 50 ms, low-frequency band, and total power, coinciding with decreased stress index, was detected at 9 min of recovery. A difference between RMSSD and SD1 was observed between groups, in which they were higher in horses cooling with cold-saline water when compared to cold water at 5 min after cooling began. An increase in VLF was seen at 9 min only in horses cooled with cold-saline water. In conclusion, different water types distinctly impacted HRV in horses. The predominant PNS activity in horses recovering with cold-saline water reflects its positive impact on cooling during an endurance ride.

Associations between physical fitness, body composition, and heart rate variability during exercise in older people: exploring mediating factors.

Age-related changes in body composition affect physical fitness in older adults. However, whether the autonomic response is associated with body fat percentage and its implication for physical fitness is not fully understood. To understand the association between physical fitness, body composition, and heart rate variability in older people and its mediating factors. A cross-sectional study with 81 older adults was conducted, assessing Short Physical Performance Battery (SPPB), Two-minute Step Test (TMST), body composition, and cardiac autonomic response. Correlation and mediation analyses were performed. Body fat percentage negatively correlated with physical fitness (SPPB: r=-0.273, p=0.015; TMST: r=-0.279, p=0.013) and sympathetic activity (sympathetic nervous system (SNS) index: r=-0.252, p=0.030), yet positively correlated with parasympathetic tone (root mean square of successive differences (RMSSD): r=0.253, p=0.029; standard deviation of NN intervals (SDNN): r=0.269, p=0.020). Physical fitness associated with sympathetic nervous system index (SPPB: r=0.313, p=0.006; TMST: r=0.265, p=0.022) and parasympathetic nervous system index (TMST: r=-0.344, p=0.003). Muscle mass mediated body fat's impact on physical fitness, while physical fitness mediated body fat's impact on autonomic response. Body composition and cardiac autonomic response to exercise are associated with physical fitness in older people, highlighting a possible protective effect of muscle mass against the decline in physical fitness associated with increased body fat.

Heart rate variability and perception of mental stress among medical students and residents at an emergency department

BackgroundWhen Medical Residents (MR) and Medical Students (MS) are assigned to the demanding environment of an Emergency they inevitably encounter stress. The aims of this study are to measure short-term heart rate variability (HRV) before and after shifts, estimate perceived stress levels, and assess the recovery patterns after their shifts. MethodsWe assessed HRV parameters in MS and MR using the wristband physiological monitor Polar® Verify Sense before and after day (DS) and night shifts (NS). Perceived stress levels were evaluated using the simplified State Trait Anxiety Inventory (STAI-S6) and the Subjective Units of Distress Scale. ResultsThis study included 60 participants of which 55% were female with a mean age of 26 years. MS presented significant reduction in sympathetic nervous system index after DS [0.68 (0.01–2.42) vs −0.22 (−0.75–1.13), p < 0.01] and NS [0.87 (−0.28–1.45) vs 0.06 (−0.70–1.04), p < 0.01], while MR maintained the same levels of sympathetic activity [DS: 1.17 (0.04 –2.88) vs 0.93 (0.50–1.41), p = 0.14; NS: 1.37 (0.76–2.21) vs 1.29 (0.35–2.18), p = 0.40]. Psychological data from STAI-S6 showed statistically significant differences when comparing before and after DS in both groups, with more perceived stress after than before DS (MS: 12 ± 4 vs 14 ± 4, p = 0.04; MR: 14 ± 4 vs 16 ± 4, p = 0.04), which was not observed at NS (MS: 12 ± 3 vs 12 ± 3, p = 0.84; MR: 15 ± 3 vs 15 ± 4, p = 0.40). ConclusionsShort-term HRV recordings before and after day or night shifts among MR and MS revealed heightened sympathetic activity preceding each shift, with a more sustained increase observed in the MR population and more perceived stress after day shifts in both groups.

Effect of Exercise in a Vector-Protected Arena for Preventing African Horse Sickness Transmission on Physiological, Biochemical, and Behavioral Variables of Horses

During an African horse sickness (AHS) outbreak, horses were able to exercise daily in a net-covered arena, yet the physiological responses to exercise in a netted arena was unknown. In a cross-over study design, eight horses performed a 39-minute aerobic exercise in conventional (CA) and vector-protected arenas (VPA). Horses were slower in some gaits and covered less distance in the VPA arena (P < .01). Cortisol release, hematology, and heart rate variability (HRV) were also examined. An interaction between the riding arena and time was observed in hematocrit (P = .0013), hemoglobin (P = .0012), and red blood cell count (P = .0027) and HRV variables, including mean beat-to-beat (RR) intervals (P < .0001), mean heart rate (P < .0001), sympathetic nervous system (SNS) index (P = .0038) and parasympathetic nervous system (PNS) index (P < .0001). Cortisol concentrations increased during exercise and 30 minutes postexercise in both arenas. Hematocrit, hemoglobin, and red blood cell count increased immediately postexercise in horses in VPA while remaining high from immediate post-exercise to 60 minutes postexercise in horses in CA. HRV decreased during exercise and was not different between horses in both arenas, but a higher RR interval and PNS index, corresponding to lower heart rate and SNS index, were detected during 30 to 60 minutes postexercise in horses in the VPA compared to the CA. Riding horses in different arenas impacted hematological and HRV variables. The greater RR intervals and PNS index, coinciding with the lower SNS index and heart rate, indicated parasympathetic dominance post-exercise in horses in VPA compared to CA.

Activation of the stress response among the cardiac surgical residents: comparison of teaching procedures and other (daily) medical activities

BackgroundThe aim of this Pilot study was to investigate the cardiac surgical residents’ workload during different surgical teaching interventions and to compare their stress levels with other working time spent in the intensive care unit or normal ward.MethodsThe objective stress was assessed using two cardiac surgical residents’ heart rate variability (HRV) both during surgical activities (32 selected teaching operations (coronary artery bypass graft n = 26 and transcatheter aortic valve implantation n = 6), and during non-surgical periods. Heart rate, time and frequency domains as well as non-linear parameters were analyzed using the Wilcoxon test.ResultsThe parasympathetic activity was significantly reduced during the surgical phase, compared to the non-surgical phase: Mean RR (675.7 ms vs. 777.3 ms), RMSSD (23.1 ms vs. 34.0 ms) and pNN50 (4.7% vs. 10.6%). This indicates that the residents had a higher stress level during surgical activities in comparison to the non-surgical times.The evaluation of the Stress Index during the operations and outside the operating room (8.07 vs. 10.6) and the parasympathetic nervous system index (− 1.75 to − 0.91) as well as the sympathetic nervous system index (1.84 vs. 0.65) confirm the higher stress level during surgery. This can be seen too used the FFT Analysis with higher intraoperative LF/HF ratio (6.7 vs. 3.8).ConclusionHRV proved to be a good, objective method of identifying stress among physicians both in and outside the operating room. Our results show that residents are exposed to high psychological workloads during surgical activities, especially as the operating surgeon.

Directional effects of whole-body spinning and visual flow in virtual reality on vagal neuromodulation.

Neural circuits allow whole-body yaw rotation to modulate vagal parasympathetic activity, which alters beat-to-beat variation in heart rate. The overall output of spinning direction, as well as vestibular-visual interactions on vagal activity still needs to be investigated. This study investigated direction-dependent effects of visual and natural vestibular stimulation on two autonomic responses: heart rate variability (HRV) and pupil diameter. Healthy human male subjects (n = 27) underwent constant whole-body yaw rotation with eyes open and closed in the clockwise (CW) and anticlockwise (ACW) directions, at 90°/s for two minutes. Subjects also viewed the same spinning environments on video in a VR headset. CW spinning significantly decreased parasympathetic vagal activity in all conditions (CW open p = 0.0048, CW closed p = 0.0151, CW VR p = 0.0019,), but not ACW spinning (ACW open p = 0.2068, ACW closed p = 0.7755, ACW VR p = 0.1775,) as indicated by an HRV metric, the root mean square of successive RR interval differences (RMSSD). There were no direction-dependent effects of constant spinning on sympathetic activity inferred through the HRV metrics, stress index (SI), sympathetic nervous system index (SNS index) and pupil diameter. Neuroplasticity in the CW eyes closed and CW VR conditions post stimulation was observed. Only one direction of yaw spinning, and visual flow caused vagal nerve neuromodulation and neuroplasticity, resulting in an inhibition of parasympathetic activity on the heart, to the same extent in either vestibular or visual stimulation. These results indicate that visual flow in VR can be used as a non-electrical method for vagus nerve inhibition without the need for body motion in the treatment of disorders with vagal overactivity. The findings are also important for VR and spinning chair based autonomic nervous system modulation protocols, and the effects of motion integrated VR.

Changes in vascular function and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight

This study aimed to evaluate vascular function changes and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight. This prospective study performed in pregnant (PG) women and after delivery (not pregnant: NPG) evaluated the endothelial function (EF) and arterial stiffness (AS) by a non-invasive method. We evaluated the heart rate variability (HRV), parasympathetic nervous system (PNS), sympathetic nervous system (SNS) indexes by electrocardiogram (5 min) and the urinary nitrite excretion (NOx). PG increased EF and NOx and decreased AS and HRV. PG decreased the PNS index and augmented the SNS index. The new-born weight positively correlated with the PNS index (Pearson’s r: 0.4291; p<.05), NOx, HRV and negatively correlated with AS. In summary, in pregnancy, although haemodynamically, the SNS activation plays a compensatory role, the low rates of PNS inhibition are essential to ensure normal foetal growth. Impact Statement What is already known on this subject? In pregnancy, there are adaptive physiological changes in the cardiovascular system that include increases of EF and decreases AS with an SNS activation. The study of HRV lets to predict the SNS and PNS balance and how they affect blood pressure and vascular function. What the results of this study add? Although it is known that SNS activation plays a compensatory role in healthy pregnancy, this study adds the critical role of PNS. Early in pregnancy, the low rates of PNS inhibition are essential to ensure normal foetal growth. What the implications are of these findings for clinical practice and/or further research? The present results show a potential predictive value of SNS and PNS activity early in pregnancy. It will provide valuable information not only on the pregnant woman's vascular function but also on the new-born weight.

Acute Effects of Foot Reflexology Massage on Arterial Pulse Wave Characteristics after Aerobic-based and Anaerobic-based Intermittent Exercises: A Preliminary Study

Aims:This study used pretest-posttest randomized group comparison to investigate the acute effects of foot reflexology massage (FRM) intervention on the pulse harmonic and parasympathetic modulation after repeated sprint ability test (RSA) and Yo Yo intermittent recovery test level 1 (YOYO).Background:The arterial pulse wave characteristics (APW) is a physiological indicator of peripheral arterial compliance. Reflexology massage is a non-invasive intervention to improve arterial compliance. However, the acute effect of FRM on APW after intense exercise has not been examined.Objective:The purpose of this study was to investigate the acute effect of FRM after short-term bouts of anaerobic-based and aerobic-based intermittent exercises.Methods:Twenty-six collegiate male football/futsal players voluntarily participated in this study. All participants were randomly assigned to FRM group (n= 14) or control group (n= 12). The participants performed RSA and YOYO exercise protocols at least 3 days apart within a week. The electrocardiography (ECG), and APW of right hand (RH), left hand (LH), and left foot (LF) were recorded for 10 min in supine position before and after interventional/control period. A standard of 30 min FRM was given immediately after exercises, whereas those of control group were requested to rest comfortably on a massage table for 30 min. Non-parametric statistical analyses (The Mann-Whitney rank and Wilcoxon signed rank test) were used to compare the measured variables.Results:The results showed different characteristics of sympathetic nervous system index after RSA and YOYO protocols in the FRM and control groups [FRM: RSA (p= 0.01); Control: YOYO (p&lt; 0.01)]. The results also identified similar exercise-induced modulation of 1stand 2ndpulse harmonics in LF location with or without FRM treatment.Conclusion:The FRM intervention demonstrated minor impact on the recovery of APW and parasympathetic modulation after RSA and YOYO exercises.Clinical Trail Registration Number: NCT03821805

Autonomic dysregulation in acute ischemic stroke patient with insomnia

ObjectiveThis study aimed to assess autonomic dysregulation by measuring Heart Rate Variability (HRV) parameters in acute ischemic stroke patients with insomnia. MethodsThis was a descriptive observational study on 5 participants (4 females and one male) with acute ischemic stroke and insomnia. All participants were assessed through the Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI) and then tested using a Polar H10 device for 5min recording during night sleep. The collected data analyzed by Kubios HRV Analysis Software 3.2 (MATLAB, Kuopio, Finland). ResultsThis study showed that all participants (age 51.2±12.61) had subthreshold to moderate insomnia based on ISI (14.8±2.48) and had poor sleep quality based on PSQI (16.4±3.72). There was an increase of mean heart rate (HR) (81.8±13.86), root mean square of successive differences (rMSSD) (46.6±38.05), and sympathetic nervous system index (SNS Index) (1.542±1.567), as well as the decrease of standard deviation of normal-normal interval (SDNN) (37.8±20.53), low frequency (LF) (449.2±371.8), high frequency (HF) (812.6±773.8), LF/HF (1.89±1.72), and parasympathetic nervous system index (PNS Index) (−0.462±1.210). ConclusionsThe Analysis of HRV showed an autonomic dysregulation in the form of parasympathetic dysfunction and sympathetic hyperactivation during night sleep in the acute phase of ischemic stroke with insomnia.

Sympathetic and Vagal Responses Elicited by Acute Stress in Rats.

IntroductionAcute emotional stress triggers autonomic responses that affect sympathovagal balance. However, the temporal pattern of changes in each autonomic arm during stress and recovery remains unclear. Therefore, we analyzed separately sympathetic and vagal activity, elicited by acute unpredictable stress in a rat model.MethodsContinuous electrocardiographic recording was performed during (32 minutes) and after (two hours) successive use of restraint and air-jet stress in 10 rats, whereas five rats served as controls. Sympathetic and vagal indices were calculated non-invasively after heart rate variability analysis. Voluntary motion was quantified during recovery, as an index of continuing anxiety.ResultsThe sympathetic nervous system index increased during stress and remained elevated during the initial stage of recovery. The parasympathetic nervous system index decreased immediately after the onset of stress and remained low throughout the observational period. During recovery, voluntary activity was more pronounced in the stress group than in the controls.ConclusionSuccessive restraint and air-jet stress in rats increased sympathetic activity and decreased vagal activity. These changes displayed only partial recovery post-stress and were accompanied by enhanced voluntary motion. Our findings may be important in the evaluation of the cardiac electrophysiologic implications of autonomic changes elicited by acute emotional stress.

The effect of whole body vibration by sonic waves on mood, the autonomic nervous system, and brain function in elderly

The purpose of this study was to clarify the effect of sonic wave vibration (SWV) on mood, the autonomic-nervous system, brain function and cognitive function in elderly people. We randomly assigned 24 late-stage elderly people (M 88.0±5.0 yrs) into a SWV group and a control group. The SWV group conducted 10 minutes of SWV per day, 5 days a week for 8 consecutive weeks. For evaluation purposes, we analyzed the moods with TDMS, heart rate variability (HRV), resting energy expenditure (REE), and brain activation during the Stroop test using near-infrared spectroscopy (NIRS). The stability level and pleasure level of mood increased significantly immediately after SWV. Simultaneously, the levels of the parasympathetic nervous system index of HRV significantly increased while the levels of the sympathetic nervous system index significantly decreased. REE also significantly increased. These results suggest that SWV has a relaxation effect as well as increasing the energy expenditure for elderly people. After intervention, Stroop B's execution time significantly decreased suggesting an improvement in the processing speed. The NIRS revealed that SWV may therefore activate the frontal lobe function. These results suggest that SWV may have a positive effect on mood, the autonomic nervous system, cognitive function and brain functions, and thus such treatment may be useful for elderly people.

48-LB: The Effect of Acute Psychosocial Stress in Adults with Type 1 Diabetes

The effects of acute psychological stress, heart rate variability (HRV), an indicator of autonomic function and glycemic variability (GV) have not been extensively researched in type 1 diabetes (T1D). The aim of this study is to explore the effect of acute psychosocial stress on HRV and GV in people with T1D. Methods: Eleven participants with T1D (33.00 ± 11.25 years) participated in the study. To assess acute mental stress, the subjects 1) participated in the Trier Social Stress Test (TSST); and 2) played competitive video games (Nintendo Switch™). The TSST followed standardized procedures whereby stress was induced asking participants to provide a job talk and arithmetic in front of two judges. Participants played the Mario Kart to go-kart races (10 minutes) and rotated their controllers to untangle the Treasure Chest (10 minutes). Resting HRV and GV were obtained. The subjects wore a continuous glucose monitor and a Zephyr Bioharness™ to record GV and HRV, respectively. Nonparametric, paired samples T-tests were conducted using SPSS 24. Results: During TSST, there were significant differences between the resting and TSST testing period in the sympathetic nervous sympathetic nervous system index (.57 ± 1.33 vs. 1.36 ± 1.40; z = -2.845, respectively; p &amp;lt;.01; and stress index (8.17 ± 3.69 vs. 10.27 ± 5.69; z = -2.578, respectively; p &amp;lt;.05). When subjects were playing video games, there were significant differences in the parasympathetic nervous sympathetic nervous system index (-.09 ± 1.75 vs. -.87 ± 1.05; z = -2.134, respectively; p &amp;lt;.05) compared to a resting period. However, there were no significant differences in GV compared to a resting period in during TSST and playing video game. Conclusion: This study suggests that the TSST induced stress in people with T1D, increased sympathetic activity; however, the TSST did not change glycemic variability. Playing competitive video game did not appear to neither induces stress nor affected glycemic variability. The competitive video game did not cause stress compared to TSST. Disclosure M. Park: None. Y. Song: None. M. Chu: None. M. Sevil: None. N. Hobbs: None. L. Sharp: None. A. Cinar: Research Support; Self; Dexcom, Inc., JDRF. Stock/Shareholder; Self; Dexcom, Inc., Eli Lilly and Company, Insulet Corporation, Medtronic, Novo Nordisk A/S, Tandem Diabetes Care. L.T. Quinn: None. Funding JDRF

The potential of applying immersive virtual environment to biophilic building design: A pilot study

Biophilic design is a popular form of sustainable building design because of its potential to contribute to human health and wellbeing. While many design processes are now mediated by computer technologies such as immersive virtual environments (IVEs), the reliability of IVEs to create the same benefits of biophilic designs as in-situ is yet to be determined. To this end, we conducted a comparative study to measure participants’ mood, cognitive performance, and stress level in in-situ and IVE experiment settings. A within-subject experimental design with thirty-five college students was applied to both in-situ and IVE experiments. The positive and negative scale (PANAS), visual working memory performance, and the sympathetic nervous system index and parasympathetic nervous system index were used as measures for mood, cognitive performance, and stress level of a participant, respectively. We found that natural element exposure in IVEs reduced negative mood in the same way as natural element exposure in-situ. However, we did not find the same for positive affect, visual working memory, and stress level tests. Factors such as the experimental procedure, exposure time to nature in both in-situ and IVE settings, and characteristics of participants may contribute to the results. Future research is needed to further investigate the impact of such factors and develop reliable experimental protocols.

In sync: Physiological correlates of behavioral synchrony in infants and mothers.

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. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Impact of 6‐month Caloric Restriction on Autonomic Nervous System Activity in Healthy, Overweight, Individuals

Caloric restriction (CR) increases maximum lifespan but the mechanisms are unclear. Dominance of the sympathetic nervous system (SNS) over the parasympathetic nervous system (PNS) has been shown to be a strong risk factor for cardiovascular disease. Obesity and aging are associated with increased SNS activity, and weight loss and/or exercise seem to have positive effects on this balance. We therefore evaluated the effect of different approaches of CR on autonomic function in 28 overweight individuals participating in the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) trial. Participants were randomized to either control, CR: 25% decrease in energy intake, CREX: 12.5% CR + 12.5% increase in energy expenditure, or LCD: low-calorie diet until 15% weight reduction followed by weight maintenance. Autonomic function was assessed by spectral analysis of heart-rate variability (HRV) while fasting and after a meal. Measurements were performed at baseline and 6 months. HR and SNS index decreased and PNS index increased in all intervention groups but reached significance only in CREX. HR and SNS index increased and PNS index decreased in response to the meal in all intervention groups. The results therefore suggest that weight loss improved SNS/PNS balance especially when CR is combined with exercise.

Changes of elastic properties of central arteries during acute static exercise and lower body negative pressure

The aim of this investigation was to determine the acute effects of isometric fatiguing handgrip (IFHG) and lower body negative pressure (LBNP) on indices of central arterial stiffness. Thirteen subjects were studied. Renal blood velocity (Duplex Ultrasound) and blood pressure (Finapres) were monitored during IFHG and LBNP at -30 and -50 mmHg. Radial pulse-wave forms were recorded by applanation tonometry. Central aortic waveforms and other hemodynamic parameters were assessed using the Sphygmocor software. Renal vascular resistance index (RVRI; mean BP/renal blood velocity) was used as index of sympathetic nervous system (SNS) engagement. RVRI increased during both IFHG and LBNP indicating that SNS was engaged; however, BP increased only during the IFHG. Pulse-wave analysis showed that during the IFHG protocol the transit time of the pulse wave decreased and the peripheral pulse pressure/nonaugmented central pulse pressure ratio increased from baseline. Both of these measurements suggest an increase in central large artery stiffness. During LBNP no changes in the indices of central stiffness were noted, in spite of a similar level of sympathetic system engagement. Heart rate increased during both protocols, whereas augmentation index increased during the IFHG protocol and decreased during the LBNP. Our major conclusion was that blood pressure rather than sympathetic activity seems to play the major role in modulating the elastic properties of the central arteries. The decrease in augmentation index during the LBNP protocol can be attributed to the increased heart rate, given that there is a negative correlation between these two parameters.