Index Of Sympathetic Nervous Activity Research Articles

Local alternating heat and cold stimulation affects hemodynamics and oxygenation in fatigued muscle tissue and autonomic nervous activity: a single-arm interventional study

BackgroundLocal alternating heat and cold stimulation as an alternative to contrast bath may cause intermittent vasoconstriction and vasodilation, inducing a vascular pumping effect and consequently promoting increased tissue blood flow and oxygenation. This study aimed to examine the effects of local alternating heat and cold stimulation, using a wearable thermal device, on the hemodynamics of fatigued muscle tissue and autonomic nervous activity.MethodsTwenty healthy individuals experienced fatigue in the periarticular muscles of the shoulder joint due to a typing task. Local alternating heat and cold stimulations were then applied to the upper trapezius muscle. Muscle hardness was measured using a muscle hardness meter, and muscle tissue hemodynamics and oxygenation were evaluated using near-infrared spectroscopy before and after the stimulation. Autonomic nervous activity was also evaluated using heart rate variability.ResultsAlternating heat and cold stimulation decreased muscle hardness of the fatigued trapezius muscle from 1.38 ± 0.15 to 1.31 ± 0.14 N (P < 0.01). The concentration of total hemoglobin in the trapezius muscle tissue increased from − 0.21 ± 1.36 to 2.29 ± 3.42 µmol/l (P < 0.01), and the tissue hemoglobin oxygen saturation also increased from 70.1 ± 5.4 to 71.1 ± 6.0% (P < 0.05). Additionally, the heart rate variability parameter, which is an index of sympathetic nervous activity, increased from 3.82 ± 2.96 to 6.86 ± 3.49 (P < 0.01). A correlation was found between increased tissue hemoglobin oxygen saturation and increased parameters of sympathetic nervous activity (r = 0.50, P < 0.05).ConclusionsLocal alternating heat and cold stimulation affected the hemodynamic response in fatigued muscle tissue and autonomic nervous activity. This stimulation is more efficient than conventional contrast baths in terms of mobility and temperature control and has potential as a new versatile therapeutic intervention for muscle fatigue.Trial registrationUMIN-CTR (UMIN000040087: registered on April 7, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045710. UMIN000040620: registered on June 1, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046359).

Physiological adjustment effect of visual stimulation by fresh rose flowers on sympathetic nervous activity.

As modern societies are often stressful due to urbanization and artificialization, the physiological relaxing effects of natural environments or nature-derived stimuli on humans have attracted attention and scientific data are being accumulated. It is known that there is inter-individual variation in these effects. The study aim was to apply the law of initial values to investigate the physiological adjustment effect of viewing fresh roses on sympathetic nervous activity. In this crossover study, a total of 214 high school students, office workers, healthcare workers, and elderly people were analyzed. The participants viewed fresh roses in a vase for 4 min. In the control condition, participants did not view any fresh roses during the period. To offset any order effect, participants received visual stimuli in the order of fresh roses then the control (no fresh roses) or the control and then fresh roses. ln (LF/HF) of heart rate variability (HRV) obtained from a-a interval measurements using an acceleration plethysmograph and used as an index of sympathetic nervous activity. The initial value was ln (LF/HF) of HRV during the control viewing (no fresh roses), and the change value was ln(LF/HF) of HRV during visual stimulation by fresh roses minus the control viewing. The correlation between the two was assessed by determining Pearson's correlation coefficient r, which was significantly negative. A physiological adjustment effect was observed such that participants with high initial sympathetic nervous activity showed a decrease in activity after visual stimulation with fresh roses, whereas participants with low initial activity showed an increase.

The ratio of heart rate to heart rate variability reflects sympathetic activity during incremental cycling exercise

ABSTRACT A low-frequency to a high-frequency component ratio (LF/HF) in heart rate variability (HRV) may not accurately reflect sympathetic nervous activity during exercise. Thus, a valid HRV-based index of sympathetic nervous activity is needed. Therefore, the heart rate to LF ratio (Heart rate/LF) was evaluated as sympathetic nervous activity index which is reflected by catecholamine levels during incremental exercise. In this study, 15 healthy adults performed an incremental exercise test using a cycle ergometer. HRV was derived from electrocardiography and HRV components related to the autonomic nervous system were obtained using frequency analysis. Heart rate/LF was calculated using the heart rate and LF component produced by HRV analysis. Catecholamine, blood lactate levels and respiratory gas were also measured throughout the exercise test. While LF/HF did not increase with increasing exercise intensity, Heart rate/LF non-linearly increased during the incremental exercise test, as did noradrenaline and blood lactate. Interestingly, Heart rate/LF values were positively correlated with noradrenaline (ρ = 0.788, p < 0.05) and blood lactate (ρ = 0.802, p < 0.05) levels and carbon dioxide production (ρ = 0.903, p < 0.05) from at rest through the exercise stages. Heart rate/LF reflects sympathetic nervous activity and metabolic responses during incremental cycling exercise and has potential as an HRV index of sympathetic nervous activity during exercise. Trial registration: UMIN Japan identifier: UMIN000039639..

Effects of occlusal disharmony on cardiac fibrosis, myocyte apoptosis and myocyte oxidative DNA damage in mice.

Occlusal disharmony leads to morphological changes in the hippocampus and osteopenia of the lumbar vertebra and long bones in mice, and causes stress. Various types of stress are associated with increased incidence of cardiovascular disease, but the relationship between occlusal disharmony and cardiovascular disease remain poorly understood. Therefore, in this work, we examined the effects of occlusal disharmony on cardiac homeostasis in bite-opening (BO) mice, in which a 0.7 mm space was introduced by cementing a suitable applicance onto the mandibular incisior. We first examined the effects of BO on the level of serum corticosterone, a key biomarker for stress, and on heart rate variability at 14 days after BO treatment, compared with baseline. BO treatment increased serum corticosterone levels by approximately 3.6-fold and the low frequency/high frequency ratio, an index of sympathetic nervous activity, was significantly increased by approximately 4-fold by the BO treatment. We then examined the effects of BO treatment on cardiac homeostasis in mice treated or not treated with the non-selective β-blocker propranolol for 2 weeks. Cardiac function was significantly decreased in the BO group compared to the control group, but propranolol ameliorated the dysfunction. Cardiac fibrosis, myocyte apoptosis and myocyte oxidative DNA damage were significantly increased in the BO group, but propranolol blocked these changes. The BO-induced cardiac dysfunction was associated with increased phospholamban phosphorylation at threonine-17 and serine-16, as well as inhibition of Akt/mTOR signaling and autophagic flux. These data suggest that occlusal disharmony might affect cardiac homeostasis via alteration of the autonomic nervous system.

Suppressed baroreflex peripheral arc overwhelms augmented neural arc and incapacitates baroreflex function in rats with pulmonary arterial hypertension.

What is the central question of this study? The impact of pulmonary arterial hypertension on open-loop baroreflex function, which determines how powerfully and rapidly the baroreflex operates to regulate arterial pressure, remains poorly understood. What is the main finding and its importance? The gain of the baroreflex total arc, indicating the baroreflex pressure-stabilizing function, is markedly attenuated in rats with monocrotaline-induced pulmonary arterial hypertension. This is caused by a rightward shift of the baroreflex neural arc and a downward shift of the peripheral arc. These findings contribute greatly to our understanding of arterial pressure regulation by the sympathetic nervous system in pulmonary arterial hypertension. Sympathoexcitation has been documented in patients with established pulmonary arterial hypertension (PAH). Although the arterial baroreflex is the main negative feedback regulator of sympathetic nerve activity (SNA), the way in which PAH impacts baroreflex function remains poorly understood. In this study, we conducted baroreflex open-loop analysis in a rat model of PAH. Sprague-Dawley rats were injected with monocrotaline (MCT) s.c. to induce PAH (60mgkg-1 ; n=11) or saline as a control group (CTL; n=8). At 3.5weeks after MCT injection, bilateral carotid sinuses were isolated, and intrasinus pressure (CSP) was controlled while SNA at the coeliac ganglia and arterial pressure (AP) were recorded. To examine the static baroreflex function, CSP was increased stepwise while steady-state AP (total arc) and SNA (neural arc) responses to CSP and the AP response to SNA (peripheral arc) were measured. Monocrotaline significantly decreased the static gain of the baroreflex total arc at the operating AP compared with CTL (-0.80±0.31 versus -0.22±0.22, P<0.05). Given that MCT markedly increased plasma noradrenaline, an index of SNA, by approximately 3.6-fold compared with CTL, calibrating SNA by plasma noradrenaline revealed that MCT shifted the neural arc to a higher SNA level and shifted the peripheral arc downwards. Monocrotaline also decreased the dynamic gain of the baroreflex total arc (-0.79±0.16 versus -0.35±0.17, P<0.05), while the corner frequencies that reflect the speed of the baroreflex remained unchanged (0.06±0.02 versus 0.08±0.02Hz, n.s.). In rats with MCT-induced PAH, the suppressed baroreflex peripheral arc overwhelms the augmented neural arc and, in turn, attenuates the gain of the total arc, which determines the pressure-stabilizing capacity of the baroreflex.

Instability of nocturnal parasympathetic nerve function in patients with chronic lung disease with or without nocturnal desaturation

Objective/backgroundThis study was performed to evaluate the association of nocturnal autonomic nerve (AN) dysfunction, especially parasympathetic nerve (PN) function instability, and nocturnal oxygen desaturation (NOD) in patients with chronic lung diseases (CLD).Patients and methodsTwenty-nine stable CLD patients with irreversible pulmonary dysfunction and mild-to-moderate daytime hypoxemia, 13 CLD patients receiving long-term oxygen therapy (LTOT) with maintained SpO2 >90%, and 17 senior healthy volunteers underwent two-night examinations of nocturnal AN function by pulse rate variability (PRV) instead of heart rate variation using a photoelectrical plethysmograph simultaneously monitoring SpO2 and the presence of sleep disordered breathing at home. AN function was examined by instantaneous time–frequency analysis of PRV using a complex demodulation method.ResultsThere were no significant differences in mean low frequency/high frequency (HF) ratio (index of sympathetic nerve activity) or mean HF amplitude (index of PN activity) among controls and CLD patients with and without NOD (defined as SpO2 <90% for at least 3% of total recording time at night). However, the relative times over which the same main HF peak was sustained for at least 20 seconds (%HF20sec) and 5 minutes in total recording time, indexes of PN function stability, were significantly reduced in CLD patients compared with controls, and further decreased in CLD patients with NOD compared with non-NOD. %HF20sec was significantly higher in the LTOT group than the NOD group. Furthermore, PaO2 at rest and nocturnal hypoxia were significantly correlated with PN function instability in CLD patients.ConclusionPN function is unstable at night associated with nocturnal hypoxemia in CLD patients, which may reflect poor quality of sleep.

Mozart's and Bach's music yielded little relaxation effect as indicated HR, BP, and autonomic nervous activity

BackgroundSince the Mozart effect was first reported in 1993, it has been commonly proposed that listening to music has beneficial effects on physical and mental health. The putative relaxation effect of Mozart's music has been exploited for commercial purposes. Moreover, it has been reported that Bach's music has a relaxation similar to Mozart's music. Despite these widespread claims, few scientific or clinical investigations have shown compelling evidence demonstrating relaxation effects of Mozart's and/or Bach's music.ObjectiveThe purpose of this study was to evaluate the effects of Mozart's Sonata for Four Hands in D‐major (K448) and Bach's Brandenburg Concerto No.4 in G‐major (BWV1049) on heart rate (HR), blood pressure (BP), and autonomic nervous activity in healthy young adults.MethodsWe enrolled seventeen healthy young adults with an average age of 21.9 ± 0.9 years in our study. After 10 minutes of rest, all volunteers underwent three tasks in a randomized order: an examination to induce a mental work load and two 8‐minute intervals of music listening. The control group underwent two 8‐minute periods of silence rather than music. We assessed the electrocardiogram continuously from the start of each experiment to completion. Spectral analysis was performed to determine the low frequency (LF, 0.04–0.15 Hz) and high frequency (HF, 0.15–0.40 Hz) spectral components of heart late variability (HRV). The HF component was used as an index of parasympathetic nervous activity, and the ratio of LF to HF components (LF/HF) was used as an index of sympathetic nervous activity. Additionally, we measured BP before and after each workload‐inducing examination, and after each music‐listening or silence period. The selected music consisted of K448 and BWV1049. All data are expressed as mean ± SE. One‐way repeated‐measures ANOVA and multiple comparison tests were performed to compare each index. A value of P &lt; 0.05 was considered significant.ResultsThere were significant decrease in HR and diastolic blood pressure (DBP) upon listening to K448 and BWV1049, or during silence in the case of control, but no significant change in systolic blood pressure (SBP) in any condition. HF spectral components of HRV showed insignificant changes in BWV1049 and control; however, it was significantly decreased in K448. LF/HF was not significantly lower after the examination compared to other task conditions in the K448, BWV1049, or control groups. There were no significant differences in the rate of change in HR, SBP, DBP, HF, and LF/HF during K448, BWV1049, or silence (control).ConclusionWe did not identify significant changes in HR, BP, or LF/HF in healthy young adults while they listened to K448 or BWV1049. However, HF did decrease after listening to K448. Overall, our findings suggested that Mozart's and Bach's music yielded little relaxation effect as indicated HR, BP, and autonomic nervous activity.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Change in Autonomic Nervous Activity during Ingestion of Soft Food in Older Nursing Home Residents.

The deterioration in masticatory function often seen in older adults rules out the consumption of hard foods, while a common decline in autonomic nervous response often observed in older adults may result in maladjustment to environmental stresses. The purpose of this study was to investigate whether autonomic nervous activity in older adults increased during the mastication of soft foods compared to at rest. The participants comprised 9 volunteer nursing home residents aged 78 to 100 years. All consumed soft rice as a grain dish and coarsely chopped food as side dishes. The coefficient of variation of R-R intervals (CVRR) and high-frequency (HF) power on electrocardiograph (ECG) served as indices of parasympathetic nervous activity, while the low-frequency (LF)/HF ratio served as an index of sympathetic nervous activity. Total power, reflecting the level of autonomic nervous activity, was also measured. We measured autonomic nervous activity while nursing home residents were eating lunch. HF was 3,457.4±3,037.5 ms2 at rest and 4,085.1±3,697.7 ms2 during mastication. The CVRR was 26.8±16.9% at rest and 26.1±16.1% during mastication. No significant difference was observed in HF or CVRR. On the other hand, the LF/HF ratio was 0.77±0.24 ms2 at rest and 31.0±3.77 ms2 during mastication (p=0.011). A significant difference was observed in the LF/HF ratio between the resting and masticating conditions. Total power was 6,244.1±5,752.5 ms2 at rest and 8,417.7±7,266.4 ms2 during mastication (p=0.038). A significant difference was also observed in total power between resting and masticating conditions. These results suggest that mastication of soft foods stimulates autonomic nervous activity in older adults. In conclusion, autonomic nervous activity increased during chewing soft foods compared to that during the resting level in older adults.

Effect of chewing or compressing food on autonomic nervous activity in older adults

To determine if autonomic nervous activity increases in older people during mastication and how this activity is related to the softness of food. We hypothesised that the coefficient of variation of R-R intervals (CVRR), high-frequency (HF) power, low-frequency (LF) power, LF/HF ratio and total power increase during chewing foods within the range of softness from moderate food to extremely soft food in older adults. Participants were 20 older volunteers (71-90year old). CVRR and HF on the electrocardiogram (ECG) were used as indices of parasympathetic nervous activity. LF and the LF/HF ratio on the ECG were used as indices of sympathetic nervous activity. Total power, reflecting the level of autonomic nervous activity, was also measured. Participants were asked to chew gum with three different degrees of softness, or to compress extremely soft gum between their palate and tongue. There were significant differences in HF between at resting and all chewing/compressing conditions, but no significant differences relating to food softness. There were significant differences in total power between at resting and all chewing/compressing conditions, but no significant differences relating to food softness. There were no significant differences in LF, LF/HF and CVRR among all conditions. Autonomic nervous activity, especially parasympathetic activity in older adults, increased during chewing and compressing food when compared to activity while at rest. Within the range of food's softness from moderate to extreme soft, food's softness had no measurable effect on autonomic nervous activity.

Pedometer‐determined physical activities of daily living can affect blood pressure regulation in healthy young adults after postural change

BackgroundNumerous studies have examined the effects of physical activity (PA) on blood pressure (BP) or autonomic function through exercise interventions. However, few studies have used non‐intervention methods to observe the association between pedometer‐determined physical activities of daily living and BP and autonomic function in healthy young adults.ObjectiveThe purpose of this study was to examine whether the differences in pedometer‐determined physical activities of daily living cause the variation in BP and autonomic nerve activity in healthy young adults.MethodsFourteen Japanese healthy young adults aged 20–24 years participated in this study. A pedometer was used to measure the step count and to calculate other indexes of physical activity for 1 week. It was determined that 5 individuals comprised the high PA group (≥23 METs ■ hr/wk) and 9 individuals comprised the low PA group (&lt;23 METs ■ hr/wk). Weight, height, BMI, muscle mass, body fat percentage, and basal metabolic rates were measured using a body composition analyzer. Then, we measured BP and heart rate variability at rest and during the postural change from the supine position to the sitting position. The ratio of low frequency (LF) components (0.04–0.15 Hz) to high frequency (HF) components (0.15–0.40 Hz) was used as an index of sympathetic nerve activity. HF was used as an index of parasympathetic nerve activity.ResultsThe high PA group exhibited significantly higher calorie consumption (P &lt; 0.01) and fat combustion (P &lt; 0.01). The mean diastolic blood pressure value in the sitting position (P &lt; 0.02) for the high PA group was significantly higher than that of the low PA group. After a postural change from the supine position to the sitting position, although there were no significant changes in LF/HF and HF in both groups, systolic blood pressure (SBP) in the high PA group increased significantly (P &lt; 0.05); however, the low PA group had a significant subsequent decrease in SBP after changing from the supine position to the sitting position (P &lt; 0.01).ConclusionsThrough the measurement of pedometer‐determined physical activities of daily living in healthy adults, we concluded that individuals who performed more pedometer‐determined physical activities of daily living can maintain normal responses in blood pressure after a postural change, compared to individuals who performed fewer pedometer‐determined physical activities of daily living.Support or Funding InformationThis work was supported, in part, by a Grant‐in‐aid for Scientific Research (B) (25305018) from the Japan Society for the Promotion of Science.

Does Mozart's music have a relaxation effect?

BackgroundPrevious studies have suggested that Mozart's music has a relaxation effect. In contrast, several studies have also reported that Mozart's music has an effect on enhancing the ability to focus. There is currently no consistent evidence demonstrating the effects of Mozart's music.ObjectiveThe purpose of this study was to evaluate the effects of Eine Kleine Nachatmusik (K.525), a piece representative of Mozart's music, on heart rate (HR), blood pressure (BP), and autonomic nerve activity.MethodWe performed electrocardiographic (ECG) measurements in 15 healthy young Japanese adults, aged between 19 and 24 years. None of the participants had received a specialized music education. We investigated BP and heart rate variability (HRV) in a resting state, when taking a reading‐span‐test (RST), and when listening to music. We used high frequency (HF, 0.15–0.40 Hz) components as an index of parasympathetic nerve activity and the ratio of low frequency (LF, 0.04–0.15 Hz) to HF components (LF/HF) as an index of sympathetic nerve activity. After 5 minutes at rest, a reading‐span‐test (RST) was used to place a load on participants. Then, participants used headphones to listen to K.525 and a favorite song chosen from 6 pieces of popular Japanese music in randomized order. Both K.525 and the chosen favorite song were approximately 6 minutes long. After listening to music, ECG measurement continued for 5 minutes. All data are expressed as mean ± SE. One‐way repeated‐measures ANOVA and multiple comparison tests were performed to compare each index. A value of P &lt; 0.05 was considered significant.ResultsThere was a significant decrease in HR but no significant changes in BP or LF/HF after listening to both K.525 and the favorite song. HF showed a significant increase when listening to the favorite song, whereas K.525 had no notable effect.ConclusionWe found that Mozart's music has no relaxation effect. We suggest that a favorite song has a greater activation effect on parasympathetic nerve activity.Support or Funding InformationThis work was supported, in part, by a Grant‐in‐aid for Scientific Research (B) (25305018) from the Japan Society for the Promotion of Science.

Effects of L- and N-Type Ca Channel Blocker Cilnidipine on Changes in Heart Rate and QT Interval During Dialysis

Background/Aims: Hemodialysis patients have poor prognosis due to increased prevalence of cardiovascular diseases. Treatment to suppress increases in sympathetic nerve activity and QT prolongation may have the potential to reduce the occurrence of these events. The L/N-type Calcium (Ca) channel blocker cilnidipine has unique inhibitory action to inhibit sympathetic nerve activity and in a canine model ameliorates QT prolongation. In this study, we investigated whether cilnidipine has inhibitory effects on heart rate, an index of sympathetic nerve activity, and QT prolongation in patients undergoing dialysis. Methods: An L-type Ca channel blocker amlodipine was administered for 4 weeks followed by cilnidipine treatment for 4 weeks. On the last day of each period, heart rate and corrected QT interval were estimated and compared between the two periods. Results: Cilnidipine showed greater suppression of heart rate during dialysis than did amlodipine. The corrected QT interval in one dialysis session was significantly increased, and 3 of 17 patients showed prominent QT prolongation during administration of amlodipine but not cilnidipine. Conclusion: These data suggested that cilnidipine may inhibit increases in heart rate and QT interval. Cilnidipine may have beneficial effects in reducing cardiovascular events, resulting from increased sympathetic nerve activity and lethal arrhythmias in hemodialysis patients.

Elevated HbA1c Levels Are Associated with the Blunted Autonomic Response Assessed by Heart Rate Variability during Blood Volume Reduction.

A high glycemic status increases the risk for autonomic dysfunction and cardiovascular failure. The aim of this study was to investigate time-dependent changes in the autonomic response and cardiovascular dynamics and the association between the level of hemoglobin A1c (HbA1c) and autonomic response during blood volume reduction. The study population consisted of 26 preoperative participants who were scheduled for autologous blood donation (200-400 mL of whole blood) for intraoperative or postoperative use. These participants without circulatory, respiratory, or brain disease and diabetes mellitus were grouped according to their HbA1c levels: < 6.5% (n = 18) and ≥ 6.5% (n = 8). We measured blood pressure (BP) and analyzed heart rate variability (HRV) to quantify cardiac autonomic regulation throughout blood donation. During blood volume reduction, which was about 10% of the circulating blood volume, the BP and heart rate varied within normal ranges in both groups. The high-frequency (HF) component, an index of parasympathetic nerve activity, and the ratio of low-frequency (LF) to HF components (LF/HF), an index of sympathetic nerve activity, significantly decreased and increased with the progression of blood volume reduction, respectively, in the HbA1c < 6.5% group. In contrast, in the HbA1c ≥ 6.5% group, the HF component did not significantly change, and the increase in the LF/HF ratio was delayed. Time-dependent changes in HRV were related to blood volume reduction only in the HbA1c < 6.5% group. Thus, elevated HbA1c levels are associated with the decrease in the autonomic response induced by blood volume reduction.

Blunted Autonomic Responses and Low-Grade Inflammation in Mongolian Adults Born at Low Birth Weight.

Low birth weight (LBW) has been considered as a risk factor for adult hypertension that is associated with deterioration of autonomic functions and low-grade inflammation. To explore the above effects of LBW, we measured blood pressure (BP) and heart rate variability during postural change from a supine position to a sitting position in 21 healthy Mongolian adults aged 23-34 years: 4 with LBW (birth weight < 2,500 g), 13 with normal birth weight (NBW, 2,500 g ≤ birth weight < 4,000 g), and 4 with high birth weight (HBW, ≥ 4,000 g). Mongolian population is known to have higher prevalence of hypertension. The ratio of low frequency (LF, 0.04-0.15 Hz) to high frequency components (HF, 0.15-0.40 Hz) was used as an index of sympathetic nerve activity, and HF was used as an index of parasympathetic nerve activity. In contrast to the NBW group, the LBW and HBW groups showed no significant increase in heart rate, systolic BP and LF/HF following postural change. We also measured blood cell counts and other blood parameters related to inflammation. After adjusting for age, BMI, sex and family history of hypertension, LBW was retained as an independent predictor only for higher counts of leukocytes (β = -0.51, p < 0.05), basophils (β = -0.62, p < 0.01), eosinophils (β = -0.83, p < 0.001), and platelets (β = -0.61, p < 0.05). We propose that LBW leads to blunted autonomic responses and low-grade inflammation in seemingly healthy Mongolian adults.

Physiological and psychological relaxing effects of visual stimulation with foliage plants in high school students

With lifestyles in modern society becoming increasingly stressful, there is growing interest in the physiological relaxing effects of the natural environment. Particular interest has been paid to the physiological effects of indoor plants, however, no studies have revealed the effects of such visual stimulation on minors. In this study 85 (41 male and 44 female; 16.5±0.9 years; mean±SD) students were exposed, or not as control, to a typical foliage plant, dracaena ( Dracaena deremensis ; Lemon Lime), for 3 min. Physiological indices included heart rate variability (HRV) and pulse rate, using an accelerated plethysmography at the fingertip, were collected continuously during the experiments. The results indicated that the high-frequency component (HF), a general index of parasympathetic nervous activity, was significantly higher; the low-frequency component [LF/(LF+HF)], a general index of sympathetic nervous activity, was significantly lower; and the pulse rate was significantly lower. After exposure, or not, the subjects completed a questionnaire as psychological evaluation. A 13-point rating scale was used for following parameters: comfortable-uncomfortable, relaxed-awakening, and natural-artificial. Results of the study showed that subjects felt more comfortable, relaxed and natural after visualizing the dracaena plants. Overall, the physiological and psychological relaxing effects of visual stimulation with foliage plants in high school students is confirmed.

Relationship of Heart Rate Variability to Sleepiness in Patients with Obstructive Sleep Apnea with and without Heart Failure

Many patients with severe obstructive sleep apnea (OSA) do not complain of excessive daytime sleepiness (EDS), possibly due to increased sympathetic nervous activity (SNA) and accompanying heightened alertness. We hypothesized that in patients with OSA, those without subjective EDS (Epworth Sleepiness Scale, ESS score < 11) would have higher very low frequency (VLF) heart rate variability (HRV) during sleep, reflecting greater sympathetic heart rate modulation than patients with an ESS score ≥ 11. Patients with severe OSA (AHI ≥ 30: 26 with and 65 without heart failure) were divided into those with and without EDS. Heart rate (HR) signals were acquired in stage 2 sleep during periods of recurrent apneas and hypopneas and submitted to coarse graining spectral analysis, which extracts harmonic, neurally mediated contributions to HRV from total spectral power. Because the apnea-hyperpnea cycle entrains muscle SNA at VLF (0 to 0.04 Hz), VLF power was our principal between-group comparison. Subjects without EDS had higher harmonic VLF power (944 ± 839 vs 447 ± 461 msec(2), p = 0.003) than those with EDS, irrespective of the presence or absence of heart failure (1218 ± 944 vs 426 ± 299 msec(2), p = 0.043, and 1029 ± 873 vs 503 ± 533 msec(2), p = 0.003, respectively). ESS scores correlated inversely with VLF power in all (r = -0.294, p = 0.005) and in heart failure subjects (r = -0.468, p = 0.016). Patients with severe OSA but without EDS have higher VLF-HRV than those with EDS. This finding suggests that patients with severe OSA but without EDS have greater sympathetic modulation of HRV than those with EDS that may reflect elevated adrenergically mediated alertness. Taranto Montemurro L; Floras JS; Picton P; Kasai T; Alshaer H; Gabriel JM; Bradley TD. Relationship of heart rate variability to sleepiness in patients with obstructive sleep apnea with and without heart failure.

Consciously controlled breathing decreases the high-frequency component of heart rate variability by inhibiting cardiac parasympathetic nerve activity.

Heart rate variability (HRV), the beat-to-beat alterations in heart rate, comprises sympathetic and parasympathetic nerve activities of the heart. HRV analysis is used to quantify cardiac autonomic regulation. Since respiration could be a confounding factor in HRV evaluation, some studies recommend consciously controlled breathing to standardize the method. However, it remains unclear whether controlled breathing affects HRV measurement. We compared the effects of controlled breathing on HRV with those of spontaneous breathing. In 20 healthy volunteers, we measured respiratory frequency (f), tidal volume, and blood pressure (BP) and recorded electrocardiograms during spontaneous breathing (14.8 ± 0.7 breaths/min) and controlled breathing at 15 (0.25 Hz) and 6 (0.10 Hz) breaths/min. Compared to spontaneous breathing, controlled breathing at 0.25 Hz showed a higher heart rate and a lower high-frequency (HF) component, an index of parasympathetic nerve activity, although the f was the same. During controlled breathing at 0.10 Hz, the ratio of the low frequency (LF) to HF components (LF/HF), an index of sympathetic nerve activity, increased greatly and HF decreased, while heart rate and BP remained almost unchanged. Thus, controlled breathing at 0.25 Hz, which requires mental concentration, might inhibit parasympathetic nerve activity. During controlled breathing at 0.10 Hz, LF/HF increases because some HF subcomponents are synchronized with f and probably move into the LF band. This increment leads to misinterpretation of the true autonomic nervous regulation. We recommend that the respiratory pattern of participants should be evaluated before spectral HRV analysis to correctly understand changes in autonomic nervous regulation.

Abstract 9455: Change of Heart Rate Variability and Correlation With Cardiac Function During Development Process of Chronic Heart Failure in Large Animal Model

Introduction; Heart rate variability (HRV) is conceived to have a close relationship with prognosis of heart failure (HF). However, there is few study on HRV during diagnostic and treating process of HF in clinical settings. By investigating this process, HRV may become a more useful approach for non-invasive estimation of cardiac function. In this study, we examined the change of HRV and its correlation with cardiac function throughout the entire course of progressing HF in newly developed large animal chronic heart failure (CHF) models created by combination of micro-embolization and rapid pacing. Methods; CHF was introduced in 12 adult goats (60.9±4.1 kg) by coronary microsphere embolization (50μm, 0.201±0.014 million) to the left anterior descending artery and subsequent rapid ventricular pacing (HR[[Unable to Display Character: &amp;#8786;]]200) for 5 weeks. Electrocardiogram was recorded continuously for 24 hours under pacing off per week. HRV was analyzed by Memcalc/CHIRAM (Suwa Trust, GMS Inc.), which calculated time-domain index (SDNN etc.) and frequency domain index (LF, HF etc.), evaluated correlation with left ventricle ejection fraction (EF) and cardiac output (CO). Results; Ten goats survived and developed CHF successfully, showing decreased EF (from 90.4±4.1% to 48.3±5.6%) and CO (from 5.6±0.5L/min to 4.0±0.6 L/min). All indexes of HRV were decreased along with progress of HF (SDNN decreased from 166.1±39.1msec to 51.9±33.3msec). LF/HF which is the index of sympathetic nerve activity increased from 1.4±0.9 to 10.7±8.3. A strong correlation was observed between SDNN and cardiac function (Fig). Two cases of sudden death in course showed significant decrease of HRV as compared with the surviving cases. Conclusions; HRV was decreased along with progress of HF, strongly indicating aggravation of sympathetic nerve activity. These findings suggest that HRV analysis has a potential to become a useful and reliable approach for non-invasive estimation of cardiac function and severity of HF.

Renal denervation: a potential new treatment modality for polycystic ovary syndrome?

Polycystic ovary syndrome (PCOS) is associated with sympathetic nervous system activation, insulin resistance, and blood pressure elevation. Renal nerve ablation has been demonstrated to reduce sympathetic outflow and improve blood pressure control. Here we report on the effects of renal denervation on hemodynamic, metabolic, and renal parameters in two obese PCOS patients with hypertension. Sympathetic nerve activity was assessed at baseline using microneurography and norepinephrine spillover measurements. Insulin sensitivity was assessed by euglycemic hyperinsulinemic clamp. Measurements of cystatin-C, creatinine clearance, and urinary albumin-creatinine ratio were also obtained. All measurements were repeated 3 months after bilateral renal denervation achieved via percutaneous endovascular radiofrequency ablation. Muscle sympathetic nerve activity and whole body norepinephrine spillover were substantially elevated at baseline in both patients by approximately 2.5-3-fold. Bilateral renal nerve ablation reduced both indices of sympathetic nerve activity. This was associated with moderate reductions in blood pressure and a substantial improvement in insulin sensitivity by approximately 17.5% in the absence of weight changes at 3-month follow-up. Glomerular hyperfiltration and urinary albumin excretion were also reduced. These findings corroborate the relevance of sympathetic activation in PCOS and suggest that renal denervation exerts beneficial effects not only on blood pressure control but also on insulin sensitivity, renal, and endocrine abnormalities characteristic of PCOS.

Hypertension: its effect on the stimulated release of dopamine-beta-hydroxylase in the rat.

Plasma dopamine-beta-hydroxylase (DBH) concentrations have been postulated as providing an index of sympathetic nerve activity. Using a microspectrophotometric assay system, plasma DBH concentrations have been measured in emergent blood from autoperfused heart, spleen and mesentery of normotensive, deoxycorticosterone (doca)/NaCl-treated, Goldblatt (1 kidney) renal and spontaneously hypertensive rats following sympathetic nerve outflow stimulation. Changes in plasma DBH concentrations as a result of sympathetic nerve outflow stimulation rates of 1--25 Hz for the mesentery and spleen and 1--4 Hz for the heart, were found to be frequency-dependent in all groups. Significantly greater amounts of DBH were found in the perfusate from the spleen (1--25 Hz) and mesentery (3--25 Hz) but not the heart (0.5--4Hz) of renal hypertensive rats compared with normotensive controls. Significantly greater concentrations of DBH were released from the spleen but not the mesentery in all hypertensive groups following high stimulation frequencies of 12 and 25 Hz. It is concluded that there is a relation between plasma DBH concentrations and sympathetic nerve activity. Furthermore, greater amounts of the enzyme are released from the spleen and mesentery of chronic renal hypertensive rats following sympathetic nerve stimulation.