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1.
No modulation of postprandial metabolism by transcutaneous auricular vagus nerve stimulation: a cross-over study in 15 healthy men.
Vosseler, A, Zhao, D, Fritsche, L, Lehmann, R, Kantartzis, K, Small, DM, Peter, A, Häring, HU, Birkenfeld, AL, Fritsche, A, et al
Scientific reports. 2020;(1):20466
Abstract
Experimental evidence suggests a crucial role of the autonomic nervous system in whole body metabolism with major regulatory effects of the parasympathetic branch in postprandial adaptation. However, the relative contribution of this mechanism is still not fully clear in humans. We therefore compared the effects of transcutaneous auricular vagus nerve stimulation (taVNS, Cerbomed Nemos) with sham stimulation during an oral glucose tolerance test in a randomized, single-blind, cross-over design in 15 healthy lean men. Stimulation was performed for 150 min, 30 min before and during the entire oral glucose tolerance test with stimulation cycles of 30 s of on-phase and 30 s of off-phase and a 25 Hz impulse. Heart rate variability and plasma catecholamine levels were assessed as proxies of autonomic tone in the periphery. Neither analyzed heart rate variability parameters nor plasma catecholamine levels were significantly different between the two conditions. Plasma glucose, insulin sensitivity and insulin secretion were also comparable between conditions. Thus, the applied taVNS device or protocol was unable to achieve significant effects on autonomic innervation in peripheral organs. Accordingly, glucose metabolism remained unaltered. Therefore, alternative approaches are necessary to investigate the importance of the autonomic nervous system in postprandial human metabolism.
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2.
Risk Factors Associated with Cardiac Autonomic Modulation in Obese Individuals.
Oliveira, C, Silveira, EA, Rosa, L, Santos, A, Rodrigues, AP, Mendonça, C, Silva, L, Gentil, P, Rebelo, AC
Journal of obesity. 2020;:7185249
Abstract
Obesity leads to an imbalance in the autonomic nervous system, especially in increased sympathetic modulation and decreased vagal tone, and some anthropometric, metabolic, and lifestyle variables may increase the risk of developing cardiovascular disease. Objective. To analyze the association between cardiovascular autonomic modulation and biochemical and anthropometric markers, food intake, and physical activity level in severely obese individuals. Methodology. The present study is a cutout of a randomized clinical trial "Effect of nutritional intervention and olive oil in severe obesity" (DieTBra Trial), where the baseline data were analyzed. Anthropometric data, biochemical exams, heart rate variability (HRV), accelerometry, and 24 h recall (R24H) of obese patients (body mass index BMI ≥35 kg/m2) were collected. Results. 64 obese patients were analyzed, with a mean age of 39.10 ± 7.74 years (27 to 58 years). By HRV analysis, in the frequency domain, the obese had a higher predominance of sympathetic autonomic modulation (low frequency (LF) 56.44 ± 20.31 nu) and lower parasympathetic modulation (high frequency (HF) 42.52 ± 19.18 nu). A negative association was observed between the variables Homeostasis Evaluation Model (HOMA-IR) and HF (p = 0.049). In the physical activity analysis, there was a negative association between moderate to vigorous physical activity and the sympathetic component (p = 0.043), and for sedentary time (ST), there was a negative association with HF (p = 0.049) and LF/HF (p = 0.036) and a positive association with LF (p = 0.014). For multiple linear regression, waist circumference (WC) and HOMA-IR values were negatively associated with HF (β = -0.685, p = 0.010; β = -14.989, p = 0.010; respectively). HOMA-IR (β = 0.141, p = 0.003) and the percentage of lipids ingested (β = -0.030, p = 0.043) were negatively associated with LF/HF. Conclusion. Among the cardiovascular risk variables studied, insulin resistance and central adiposity showed the greatest influence on cardiac autonomic modulation of obese, increasing the risk for cardiovascular disease.
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3.
Avocado (Persea americana) pulp improves cardiovascular and autonomic recovery following submaximal running: a crossover, randomized, double-blind and placebo-controlled trial.
Sousa, FH, Valenti, VE, Pereira, LC, Bueno, RR, Prates, S, Akimoto, AN, Kaviani, M, Garner, DM, Amaral, JAT, de Abreu, LC
Scientific reports. 2020;(1):10703
Abstract
Previous studies have demonstrated that regular avocado consumption presents advantageous effects on cardiovascular system. However, little attention has been paid to the use of avocado as a dietary supplement, in particular, for individuals involved in physical exercise training. Therefore, this study aims to evaluate the effect of acute avocado pulp intake on cardiovascular and autonomic recovery subsequent to moderate exercise. Using a crossover, randomized, double-blind and placebo-controlled trial design, 16 healthy female adults underwent two protocols: Avocado pulp (600 mg in capsule) and placebo (600 mg starch in capsule). After the ingestion of Avocado pulp or placebo, the subjects were seated for 60 min at rest, followed by running on a treadmill at a submaximal level and then remained seated for 60 min during recovery from the exercise. Heart rate (HR), heart rate variability (HRV) [rMSSD, SD1, HF (ms2)] and skin conductance were evaluated before and during exercise, as well as during recovery. HR, systolic blood pressure, HRV and skin conductance recovered faster when subjects were given avocado pulp prior to exercise. In conclusion, avocado pulp improved cardiovascular and autonomic recovery after exercise, suggesting a reduced risk of cardiovascular events after exertion. The current results support the beneficial effects of ingestion of avocado prior to submaximal treadmill running.
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4.
Ameliorating Effects and Autonomic Mechanisms of Transcutaneous Electrical Acustimulation in Patients With Gastroesophageal Reflux Disease.
Hu, Y, Zhang, B, Shi, X, Ning, B, Shi, J, Zeng, X, Liu, F, Chen, JD, Xie, WF
Neuromodulation : journal of the International Neuromodulation Society. 2020;(8):1207-1214
Abstract
BACKGROUND/AIM: Gastric dysmotility is one of pathophysiologies of gastroesophageal reflux disease (GERD). The aim of this study was to investigate the effects of transcutaneous electrical acustimulation (TEA) on gastric accommodation and gastric slow waves, and evaluate possible mechanisms in patients with GERD. METHODS Thirty patients were studied in two randomized sessions of sham-TEA and TEA with the measurements of esophageal high-resolution manometry (HRM), gastric accommodation assessed by a nutrient-drinking test, electrogastrogram (EGG), electrocardiogram (ECG), and postprandial dyspeptic symptoms. RESULTS Compared with sham-TEA, TEA improved nutrient drinking-induced fullness (42.0 ± 3.3 vs. 31.0 ± 3.5, P = 0.003) at 10 min after the drink, and belching right after the drink (22.0 ± 4.6 vs. 11.7 ± 3.1, P = 0.012) and at 10 min (16.0 ± 3.8 vs. 3.0 ± 1.5, P = 0.002) after the drink. TEA also improved gastric accommodation (954 ± 37 mL vs. 857 ± 47 mL, P = 0.001) and normalized maximal drink-induced impairment in gastric slow waves. Concurrently, TEA enhanced vagal activity assessed from spectral analysis of heart rate variability in the postprandial state (0.42 ± 0.03 vs. 0.49 ± 0.04, P = 0.039). The vagal activity was positively correlated with the percentage of normal slow waves (r = 0.528; P = 0.003) and negatively correlated with the regurgitation score (r = -0.408, P = 0.025). CONCLUSIONS Acute TEA increases gastric accommodation, improves gastric slow waves, and reduces postprandial fullness and belching, possibly mediated via the vagal mechanisms.
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5.
Cardiac pacemaker channel (HCN4) inhibition and atrial arrhythmogenesis after releasing cardiac sympathetic activation.
Chobanyan-Jürgens, K, Heusser, K, Duncker, D, Veltmann, C, May, M, Mehling, H, Luft, FC, Schröder, C, Jordan, J, Tank, J
Scientific reports. 2018;(1):7748
Abstract
Clinical trials and studies with ivabradine implicate cardiac pacemaker channels (HCN4) in the pathogenesis of atrial arrhythmias. Because acute changes in cardiac autonomic tone predispose to atrial arrhythmias, we studied humans in whom profound cardiac sympathetic activation was rapidly relieved to test influences of HCN4 inhibition with ivabradine on atrial arrhythmias. We tested 19 healthy participants with ivabradine, metoprolol, or placebo in a double blind, randomized, cross-over fashion on top of selective norepinephrine reuptake inhibition with reboxetine. Subjects underwent combined head up tilt plus lower body negative pressure testing followed by rapid return to the supine position. In the current secondary analysis with predefined endpoints before data unblinding, continuous finger blood pressure and ECG recordings were analyzed by two experienced cardiac electrophysiologists and a physician, blinded for treatment assignment. The total atrial premature activity (referred to as atrial events) at baseline did not differ between treatments. After backwards tilting, atrial events were significantly higher with ivabradine compared with metoprolol or with placebo. Unlike beta-adrenoreceptor blockade, HCN4 inhibition while lowering heart rate does not protect from atrial arrhythmias under conditions of experimental cardiac sympathetic activation. The model in addition to providing insight in the role of HCN4 in human atrial arrhythmogenesis may have utility in gauging potential atrial pro-arrhythmic drug properties.
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6.
Effect of an aerobic exercise intervention on cardiac autonomic regulation: A worksite RCT among cleaners.
Hallman, DM, Holtermann, A, Søgaard, K, Krustrup, P, Kristiansen, J, Korshøj, M
Physiology & behavior. 2017;:90-97
Abstract
OBJECTIVE The aim of this randomized controlled trial (RCT) was to determine whether aerobic exercise during work hours affects cardiac autonomic regulation in cleaners characterized by high levels of occupational physical activity and poor cardiorespiratory fitness. METHOD Eligible cleaners (n=116) were randomized to an aerobic exercise group (n=59) or a reference group (n=57) with lectures. The intervention group received two 30-min sessions per week of supervised aerobic exercise over 4months. Diurnal measurements of heart rate variability (HRV) and physical activity (accelerometry) were obtained at baseline and at 4-month follow-up. Time and frequency domain indices of HRV were derived during work, leisure time and sleep to evaluate cardiac autonomic regulation. Linear mixed models were used to determine the effect of the intervention on HRV indices, with adjustment for age, gender and daily use of antihypertensive and/or heart medication. RESULTS Compared with the reference group, the exercise group increased all HRV indices apart from a reduction in LF/HF ratio from baseline to follow-up both during work (p<0.05) and leisure (p<0.05). In contrast, during sleep, the HRV indices tended to decrease in the exercise group compared with the reference group from baseline to follow-up, being significant for the HF spectral component (p=0.03). CONCLUSION Among cleaners, a worksite aerobic exercise intervention improved cardiac autonomic regulation during work and leisure, but not during sleep. The health effect of this contrasting change in autonomic regulation needs further investigation.
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7.
Cardiac Autonomic Changes After Thoracic Sympathectomy: A Prospective, Randomized Study.
Fiorelli, A, Messina, G, Chiodini, P, Costanzo, S, Viggiano, A, Monda, M, Vicidomini, G, Santini, M
The Annals of thoracic surgery. 2017;(1):216-224
Abstract
BACKGROUND We evaluated whether cardiac autonomic changes could be associated with different extent of sympathetic nerve resection in the management of essential palmar hyperhidrosis. METHODS Sixty patients with essential palmar hyperhidrosis were randomly allocated to undergo excision of T3 ganglia (sympathicectomy group; n = 30) or to interruption of sympathetic chain at the T2 to T3 level with ganglion sparing (sympathicotomy group; n = 30). Time and frequency domains were measured with a 24-Holter monitor during daytime, nighttime, and 24-hour periods at different interval points (7 days before operation; 24 hours; and 1, 3, and 6 months later), and the differences were statistically compared. Clinical outcomes were also evaluated. RESULTS Twenty-eight of 30 patients of the sympathectomy and 29 of 30 patients of the sympathicotomy group completed the study. In both groups, we observed a significant increase (p < 0.05) of vagal activity measurements as root mean square of the successive differences of heart period; proportion of adjacent normal R-R intervals >50 ms; high frequency; and a significant decrease (p < 0.05) of adrenergic activity variables as heart rate, low frequency, and the ratio between low frequency and high frequency during daytime, nighttime, and 24-hour periods. These changes were significantly more evident (p < 0.05) in the sympathectomy group than in the sympathicotomy group. Clinical outcomes were similar between the two groups. CONCLUSIONS Endoscopic thoracic sympathectomy caused a shift of sympathovagal balance toward parasympathetic tone that seems to be associated with the extent of denervation. This trial was registered at clinicaltrials.gov as NCT02733497.
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8.
[Long-term HRV analysis shows stress reduction by magnesium intake].
Wienecke, E, Nolden, C
MMW Fortschritte der Medizin. 2016;(Suppl 6):12-16
Abstract
BACKGROUND Mental pressure and stress represent an ever-increasing socio-political challenge. The heart rate variability (HRV) measurement, which has its origin in the cardiac function diagnosis, gives information on the neurovegetative activity. A low HRV shows an imbalance of the sympathetic and parasympathetic efferents and thus is an indicator of stress. METHOD A randomized, controlled, two-armed parallel study with 100 participants and a period of 90 days was performed. Main object of investigation was to what extent the mineral magnesium, which is also a high-quality natural calcium antagonist in cardiology, can influence the sympathovagal balance, when given in combination with a strength-endurance training. The effect on intracellular magnesium concentration was investigated as an additional parameter. RESULTS In the group with daily supplementation of 400 mg of magnesium, HRV parameters clearly increased: pNN50 - an indicator of parasympathetic activity - increased. LF-HF ratio as well as stress index - low values for each represent a good balance of the vegetative nervous system - decreased. In the control group no positive changes in HRV parameters could be shown. Vagus activity, and thus the adaptive and regenerative capacity of the body, veritably increased by magnesium supplementation. No effect on the intracellular magnesium concentration could be shown in the study. CONCLUSIONS The results of this study point out that persons with mental and physical stress can benefit from a daily intake of magnesium. This might lead to an improved physiological regulation of the sympathetic and parasympathetic efferents and, furthermore, prevent magnesium deficiency and diseases such as, for example, restlessness, irritability, lack of concentration, sleep disorder or depression.
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9.
Effects of 4 month exercise on left ventricular remodeling and autonomic nervous system in hypertensive patients.
Zheng, H, Xie, N, Xu, H, Huang, J, Xie, X, Luo, M
Panminerva medica. 2016;(1):1-7
Abstract
BACKGROUND We sought to investigate effects of supervised exercise training on left ventricular remodeling, left ventricular function and autonomic nervous system of hypertensive patients without medication. METHODS Fifty borderline and mildly hypertensive patients were enrolled and randomly divided into 2 groups (25 in each). Exercise group received a 4 months' exercise program, prescribed according to their first cardiopulmonary exercise tests, while the control group received routine dietary recommendation. All patients underwent noradrenalin assay, cardiopulmonary exercise tests and echocardiographic studies at enrollment and 4 month follow-up. RESULTS At baseline no statistically difference between the two groups were observed in clinical characteristics, echographic variants or cardiopulmonary test index. Four months later, exercise group showed higher values of VO2peak, Powermax (max workload), AT (anaerobic threshold), VO2AT (VO2 at anaerobic threshold), tAT (time from beginning to anaerobic threshold) and heart rate recovery compared to the control group (P<0.05). Additionally, systolic/diastolic blood pressure decreased significantly in the exercise group compared to the control group (P<0.05). Moreover, there was significant reduction in left ventricular mass index in the exercise group (P<0.01), and there was also an inverse correlation between changes in left ventricular mass index and heart rate recovery (r=-0.52, P<0.01). CONCLUSIONS Four-month exercise training in borderline and mildly hypertensive patients not only decreased their blood pressure levels, but also induced an improvement of exercise capability, left ventricular remodeling and heart rate recovery. Heart rate recovery improvement was significantly associated with decrease of left ventricular mass index, which indicated that favorable adjustment in autonomic nervous system of exercise training might be an important pathway to reverse left ventricular remodeling.
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10.
Aerobic exercise improves cardiac autonomic modulation in women with polycystic ovary syndrome.
Sá, JC, Costa, EC, da Silva, E, Tamburús, NY, Porta, A, Medeiros, LF, Lemos, TM, Soares, EM, Azevedo, GD
International journal of cardiology. 2016;:356-61
Abstract
BACKGROUND This study aimed to evaluate the effects of aerobic exercise on cardiac autonomic modulation in women with polycystic ovary syndrome (PCOS). METHODS Thirty women with PCOS (25.8±4.8 years old; body mass index, BMI≥25 kg/m2) were divided into two groups; exercise group (n=15) and control group (n=15). R-R interval was recorded during 15-min at rest in the supine position. Heart rate variability (HRV) was analyzed by linear (rMSSD, SDNN, LF, HF, LFnu, HFnu, and LF/HF) and nonlinear methods (Shannon entropy, SE; symbolic analyses, 0 V%, 1 V%, 2LV%, and 2UV%) at baseline and after 16 weeks. The multivariate analysis of covariance was used to analyze the effects of exercise on HRV indexes, adjusted for changes in BMI, fasting insulin, and testosterone level. RESULTS The exercise group increased parasympathetic modulation (rMSSD, HF, HFnu, 2UV%; (p<0.05)) and decreased sympathetic modulation (LF, LFnu, 0 V%; (p<0.05)) independently of changes in BMI, fasting insulin, and testosterone level. Moreover, the exercise group decreased resting HR and systolic blood pressure (p<0.05). All parameters remained unchanged in the control group. CONCLUSIONS Aerobic exercise increased vagal modulation and decreased sympathetic modulation in women with PCOS. This finding reinforces the recommendations for exercise during the clinical management of these patients.