Association of intra-shift nap duration with heart rate variability in medical night shift workers.

Napping during night shifts effectively reduces disease risk and improves work performance, but few studies have investigated the association between napping and physiological changes, particularly in off-duty daily lives. Changes in the autonomic nervous system precede diseases like cardiovascular disease, diabetes, and obesity. Heart rate variability is a good indicator of autonomic nervous system. This study aimed to investigate the link between night shift nap durations and heart rate variability indices in the daily lives of medical workers. As indicators of chronic and long-term alterations, the circadian patterns of heart rate variability indices were evaluated. We recruited 146 medical workers with regular night shifts and divided them into four groups based on their self-reported nap durations. Heart rate variability circadian parameters (midline-estimating statistic of rhythm, amplitude, and acrophase) were obtained by obtaining 24-h electrocardiogram on a day without night shifts, plotting the data of the heart rate variability indices as a function of time, and fitting them into periodic cosine curves. Using clinical scales, depression, anxiety, stress, fatigue, and sleepiness were assessed. Linear regression analysis revealed a positive relationship between 61-120-min naps and 24-h, daytime, and night-time heart rate variability indices, and the parasympathetic activity oscillation amplitude (indexed by high-frequency power, the square root of the mean of the sum of squares of differences between adjacent normal intervals, standard deviation of short-term R-R-interval variability) within one circadian cycle. This study indicated that napping for 61-120 min during night shifts could benefit medical workers' health, providing physiological evidence to promote nap management.

Association of Heart Rate Variability with Pulmonary Function Impairment and Symptomatology Post-COVID-19 Hospitalization.

The persistence of symptoms beyond three months after COVID-19 infection, often referred to as post-COVID-19 condition (PCC), is commonly experienced. It is hypothesized that PCC results from autonomic dysfunction with decreased vagal nerve activity, which can be indexed by low heart rate variability (HRV). The aim of this study was to assess the association of HRV upon admission with pulmonary function impairment and the number of reported symptoms beyond three months after initial hospitalization for COVID-19 between February and December 2020. Follow-up took place three to five months after discharge and included pulmonary function tests and the assessment of persistent symptoms. HRV analysis was performed on one 10 s electrocardiogram obtained upon admission. Analyses were performed using multivariable and multinomial logistic regression models. Among 171 patients who received follow-up, and with an electrocardiogram at admission, decreased diffusion capacity of the lung for carbon monoxide (DLCO) (41%) was most frequently found. After a median of 119 days (IQR 101-141), 81% of the participants reported at least one symptom. HRV was not associated with pulmonary function impairment or persistent symptoms three to five months after hospitalization for COVID-19.

Low heart rate variability relates to the progression of gastric cancer.

BACKGROUND: Gastric cancer (GC) is one of the most common malignant gastrointestinal tumors with the high morbidity and mortality, affecting the quality of human life. This study aimed to identify the role of heart rate variability (HRV) in patients with GC. METHODS: From January 2010 to June 2014, 383 consecutive patients diagnosed with GC were enrolled in this study. Clinical and pathological information from each patient were retrospectively recorded. HRV, including standard deviation of normal-to-normal RR intervals (SDNN) and root mean square of successive differences (RMSSD), were measured by electrocardiography. RESULTS: The results showed that the SDNN and RMSSD in GC patients were 19.02 ± 13.58 ms and 21.64 ± 17.57 ms, respectively. HRV decreased with advanced clinical stage (P < 0.0001). HRV correlated with tumor size, tumor infiltration, lymph node metastasis and distant metastasis (P < 0.001); however, no correlation with tumor site and metastasis severity was found (P > 0.05). C-reactive protein (CRP) was higher in the low HRV group than that in high HRV group (P = 0.008). CONCLUSIONS: GC patients showed a lower HRV that was correlated with tumor stage. HRV decreased with tumor progression, which may be related to a mechanism involving vagal nerve excitement inhibiting the inflammatory reaction.

Vagal Nerve Activity Predicts Prognosis in Diffused Large B-Cell Lymphoma and Multiple Myeloma.

This study examined the prognostic role of vagal nerve activity in patients with relapsed/refractory diffused large B-cell lymphoma (R/R-DLBCL) treated with chimeric antigen receptor cell therapy (CAR-T) and in patients with multiple myeloma (MM) undergoing an autologous hematopoietic cell transplantation (AutoHCT). Participants included 29 patients with R/R-DLBCL and 37 patients with MM. Inclusion criteria were: (1) age over 18; (2) diagnosed with DLBCL or MM; (3) being treated with CAR-T or AutoHCT; and (4) having an ECG prior to cell transfusion. The predictor was vagal nerve activity indexed by heart rate variability (HRV) and obtained retroactively from 10 s ECGs. The main endpoint for R/R-DLBCL was overall survival (OS), and for MM the endpoint was progression-free survival (PFS). Data of 122 patients were obtained, 66 of whom were included in the study. In DLBCL, HRV significantly predicted OS independently of confounders (e.g., performance status, disease status at cell therapy), hazard ratio (HR), and 95% confidence interval (HR = 0.20; 95%CI: 0.06-0.69). The prognostic role of disease severity was moderated by HRV: among severely disease patients, 100% died with low HRV, while only 37.5% died with high HRV. In MM, HRV significantly predicted PFS (HR = 0.19; 95%CI: 0.04-0.90) independently of confounders. Vagal nerve activity independently predicts prognosis in patients with R/R-DLBCL and with MM undergoing cell therapy. High vagal activity overrides the prognostic role of disease severity. Testing the effects of vagal nerve activation on prognosis in blood cancers is recommended.

Temporal relationships among changes in the RR-interval and the powers of the low- and high-frequency components of heart rate variability in normal subjects.

Spectral analysis of heart rate variability (HRV) is widely used as a non-invasive method to assess the cardiovascular autonomic function. Of the two main frequency components of HRV, namely low-frequency (LF, 0.04-0.15 Hz) and high-frequency (HF, 0.15-0.4 Hz) components, it is generally accepted that the HF power reflects modulation of heart rate which is mediated by cardiac parasympathetic (vagal) nerve activity. In contrast, the origin and functional correlates of the LF component are still controversial. Although several lines of evidence have indicated a close correlation between LF power and the baroreflex modulation of autonomic outflows, the detailed mechanisms underlying the genesis of the LF component remain unclarified. In this study, we conducted an ultra-short-term (UST) spectral analysis of R-R interval (RRI) time series using Fast Fourier Transform (FFT) with 5- and 25-s windows to clarify the temporal relationships among transient changes in the RRI and, LF and HF powers in healthy subjects. We found that during active standing, transient RRI increases occurred sporadically. The UST spectral analysis revealed that this RRI increase was associated with a simultaneous increase in HF power which was closely linked to the prominent LF power increase. These results indicate that during active standing, increases in LF and HF powers occur simultaneously, and they may reflect enhanced cardiac vagal activity which generates transient bradycardia.

Effects of Meditation on Mental Health and Cardiovascular Balance in Caregivers.

BACKGROUND: Caring for a loved one can be rewarding but is also associated with substantial caregiver burden, developing mental outcomes and affecting happiness. The aim of this study was to determine the effects of a four-week, 16-h presential meditation program on physiological and psychological parameters and vagal nerve activity in high-burden caregivers, as compared to a control group. METHODS: A non-randomized repeated-measures controlled clinical trial was conducted. RESULTS: According to the ANCOVA results, the global happiness score (F = 297.42, p < 0.001) and the scores for all subscales were significantly higher in the experimental group than in the control group at 5 weeks. Anxiety levels were also significantly reduced in the experimental group (F = 24.92, p < 0.001), systolic (F = 16.23, p < 0.001) and diastolic blood (F = 34.39, p < 0.001) pressures, and the resting heart rate (F = 17.90, p < 0.05). HRV results revealed significant between-group differences in the HRV Index (F = 8.40, p < 0.05), SDNN (F = 13.59, p < 0.05), and RMSSD (F = 10.72, p < 0.05) in the time domain, and HF (F = 4.82 p < 0.05)) in the frequency domain, which were all improved in the experimental group after the meditation program. CONCLUSIONS: Meditation can be a useful therapy to enhance the mental health and autonomic nervous system balance of informal caregivers, improving symptoms of physical and mental overload.

Analysis of Human Acupoint Biological Information and Neural Electric Activity Based on Ultrasonographic Image.

To find out the bioelectric signal discriminative features of different acupoints at the same time and at the same acupoint, and then analyze these differences to determine the type of acupuncture points and assist in judging the patient's condition, a hardware system was designed that can collect subcutaneous potential information of acupoints. Then, the changes of ultrasonic images were analyzed after acupuncture at Zu San Li, as well as the influence of acupuncture at Zu San Li on vagal nerve activity. The hardware system is composed of 4 parts: an analog circuit module, a digital circuit module, a power module, and a host personal computer. The power module adopted dual-module power supply mode, which was composed of MC78M05CT and LM2576 and their related peripheral circuits to ensure the stability of the circuit. The analog circuit module collected the electric signals from the 2 acupoints of Zu San Li and Shang Ju Xu of the volunteers' calves through a multistage electrode probe. In the amplifier module, Butterworth filter and 50 HZ notch are used to reduce the noise of electric signals. The filtered and amplified electric signals are converted into A/D converter in the digital circuit module. Serial communication is used to transmit data to the upper computer of the personal computer to compare the noise reduction effect of acupoint information, multiple sequences of different acupoints, and multiple sequences of the same acupoint. The influence of acupuncture at the Zu San Li acupoint on the muscle tension around the acupoint was investigated by shear wave acoustic elastic imaging technology. The influence of acupuncture at this acupoint was explored on vagal nerve activity. The results show that the wavelet noise reduction method can greatly filter out the interference signals. In the case of artificial stimulation, the signal waveform of each twist shows a big increase, and the comparison shows that there is no significant change in the frequency of other bands. Through ultrasonic image evaluation, it was found that acupuncture at Zu San Li can significantly affect the mean value of Young modulus. After acupuncture at Zu San Li, the vagal activity was increased and the balance ratio of sympathetic vagal activity was reduced. Part of the potential frequency of the acupoint is extremely active, which is the response potential of the subcutaneous induction tissue at the acupoint, which proved the feasibility of collecting electric signals around the acupoints in this kind of hardware system. It is of great significance to diagnose the disease according to the characteristics of acupoint electric signals.

Heart rate variability in the prediction of survival in patients with cancer: A systematic review and meta-analysis.

PURPOSE: Although the predictive value of vagal nerve activity, indexed by heart rate variability (HRV), has been confirmed in a variety of diseases, its value in the prediction of survival in cancer patients still remains controversial. The aim of this meta-analysis was to evaluate the predictive value of HRV in cancer patients in an evidence based manner. METHODS: A systematic review and meta-analysis was conducted through a comprehensive search of the PubMed, EMBASE and the Cochrane Central Library databases for all studies regarding HRV, vagal nerve activity and cancer. Pooled data of overall survival was analyzed. RESULTS: Six studies with 1286 patients were included in our meta analysis. Analysis of the pooled data revealed that overall survival was significantly longer in the higher HRV group than in the lower HRV group (HR 0.70, 95% CI [0.60, 0.82]; P<0.001, I2=27%). CONCLUSION: The current evidence indicates a predictive value of HRV in the survival of patients with cancer and higher vagal nerve activity might predict longer survival, but the results should be applied with caution considering the heterogeneity between included studies.

The serotonin receptor mediates changes in autonomic neurotransmission and gastrointestinal transit induced by heat-killed Lactobacillus brevis SBC8803.

Lactobacilli exhibit several health benefits in mammals, including humans. Our previous reports established that heat-killed Lactobacillus brevis SBC8803 (SBC8803) increased both efferent gastric vagal nerve activity and afferent intestinal vagal nerve activity in rats. We speculated that this strain could be useful for the treatment of gastrointestinal (GI) disorders. In this study, we examined the effects of SBC8803 on peristalsis and the activity of the efferent celiac vagal nerve innervating the intestine in rats. First, we examined the effects of intraduodenal (ID) administration of SBC8803 on efferent celiac vagal nerve activity (efferent CVNA) in urethane-anesthetised rats using electrophysiological studies. The effects of intravenous injection of the serotonin 5-HT3 receptor antagonist granisetron on changes in efferent CVNA due to ID administration of SBC8803 were also investigated. Finally, the effects of oral gavage of SBC8803 on GI transit were analysed using the charcoal propulsion method in conscious rats treated with or without granisetron. ID administration of SBC8803 increased efferent CVNA. Pretreatment with granisetron eliminated SBC8803-dependent changes in efferent CVNA. Furthermore, oral gavage of SBC8803 significantly accelerated GI transit, while pretreatment with granisetron inhibited GI transit. Our findings suggested that SBC8803 increased efferent CVNA and GI transit of charcoal meal via 5-HT3 receptors. Moreover, SBC8803 enhanced the activity of efferent vagal nerve innervating the intestine and promoted peristalsis via 5-HT3 receptors.

RR interval variability during galvanic vestibular stimulation correlates with arterial pressure upon head-up tilt.

RR interval variability (RRIV) in the supine position without and with galvanic vestibular stimulation (GVS (off) and GVS (on), respectively), changes in mean arterial pressure (MAP) at the onset of 60° head-up tilt (HUT) during GVS (off), and their relationship were analyzed in 25 healthy young subjects. MAP decreased by less than 5mmHg or increased upon HUT in 12 subjects (UP), but MAP decreased by more than 5mmHg in 13 subjects (DOWN). Applying sinusoidal GVS of 2mA at a random frequency of 0.2 to 10.0Hz did not change the RR intervals or MAP. However, the high frequency component (HF) of RRIV increased in both UP and DOWN subjects. The increase in DOWN subjects was larger than that in UP subjects. The ratio of the low frequency component to HF (L/H) increased in UP subjects during GVS (on), but did not reach a significant level in DOWN subjects. The changes in the HF were significantly correlated with changes in MAP at the onset of HUT; i.e., the subjects with larger increases in the HF during GVS (on) showed larger decreases in MAP. Thus, GVS or vestibular input during HUT possibly activates the vagal nerves, and the dominance of excitation in sympathetic or vagal nerves during vestibular stimulation is important for controlling MAP at the onset of HUT.

Autonomic nerve activity and blood pressure in ambulatory dogs.

BACKGROUND: The relationship between cardiac autonomic nerve activity and blood pressure (BP) changes in ambulatory dogs is unclear. OBJECTIVE: The purpose of this study was to test the hypotheses that simultaneous termination of stellate ganglion nerve activity (SGNA) and vagal nerve activity (VNA) predisposes to spontaneous orthostatic hypotension and that specific ß2-adrenoceptor blockade prevents the hypotensive episodes. METHODS: We used a radiotransmitter to record SGNA, VNA, and BP in eight ambulatory dogs. Video imaging was used to document postural changes. RESULTS: Of these eight dogs, five showed simultaneous sympathovagal discharges in which the minute-by-minute integrated SGNA correlated with integrated VNA in a linear pattern (group 1). In these dogs, abrupt termination of simultaneous SGNA-VNA at the time of postural changes (as documented by video imaging) was followed by abrupt (>20 mm Hg over four beats) drops in BP. Dogs without simultaneous on/off firing (group 2) did not have drastic drops in pressure. ICI-118,551 (ICI, a specific ß2-blocker) infused at 3 µg/kg/h for 7 days significantly increased BP from 126 mm Hg (95% confidence interval 118-133) to 133 mm Hg (95% confidence interval 125-141; P = .0001). The duration of hypotension (mean systolic BP <100 mm Hg) during baseline accounted for 7.1% of the recording. The percentage was reduced by ICI to 1.3% (P = .01). CONCLUSION: Abrupt simultaneous termination of SGNA-VNA was observed at the time of orthostatic hypotension in ambulatory dogs. Selective ß2-adrenoceptor blockade increased BP and reduced the duration of hypotension in this model.

Myocardial repolarization dispersion and autonomic nerve activity in a canine experimental acute myocardial infarction model.

BACKGROUND: Evidence from a canine experimental acute myocardial infarction (MI) model shows that until the seventh week after MI, the relationship between stellate ganglion nerve activity (SGNA) and vagal nerve activity (VNA) progressively increases. OBJECTIVE: The purpose of this study was to evaluate how autonomic nervous system activity influences temporal myocardial repolarization dispersion at this period. METHODS: We analyzed autonomic nerve activity as well as QT and RR variability from recordings previously obtained in nine dogs. From a total of 48 short-term ECG segments, 24 recorded before and 24 recorded 7 weeks after experimentally-induced MI, we obtained three indices of temporal myocardial repolarization dispersion: QTe (from Q-wave to T-wave end), QTp (from Q-wave to T-wave peak), and Te (from T-wave peak to T-wave end) variability index (QTeVI, QTpVI, TeVI). We also performed heart rate variability power spectral analysis on the same segments. RESULTS: After MI, all the QT variables increased QTeVI (median [interquartile range]) (from -1.76[0.82] to -1.32[0.68]), QTeVI (from -1.90[1.01] to -1.45[0.78]), and TeVI (from -0.72[0.67] to -0.22[1.00]), whereas all RR spectral indices decreased (P <.001 for all). Distinct circadian rhythms in QTeVI (P <.05,) QTpVI (P <.001) and TeVI (P <.05) appeared after MI with circadian variations resembling that of SGNA/VNA. The morning QTpVI and TeVI acrophases approached the SGNA/VNA acrophase. Conversely, the evening QTeVI acrophase coincided with another SGNA/VNA peak. After MI, regression analysis detected a positive relationship between SGNA/VNA and TeVI (R(2): 0.077; ß: 0.278; p< 0.001). CONCLUSION: Temporal myocardial repolarization dispersion shows a circadian variation after MI reaching its peak at a time when sympathetic is highest and vagal activity lowest.

Eucommia ulmoides Oliv.: ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Eucommia ulmoides Oliv. (Family Eucommiaceae), also known as Dù-zhòng (Chinese: ), Tuchong (in Japanese), is the sole species of the genus Eucommia. The leaf, stem, and bark as well as staminate flower of Eucommia ulmoides have been traditionally used to cure many diseases in China, Japan, Korea, among others. The aim of this review is to comprehensively outline the botanical description, ethnopharmacology, phytochemistry, biological activities, and toxicology of Eucommia ulmoides and to discuss possible trends for further study of Eucommia ulmoides. MATERIALS AND METHODS: Information on Eucommia ulmoides was gathered via the internet (using Pub Med, Elsevier, Baidu Scholar, Google Scholar, Medline Plus, ACS, CNKI, and Web of Science) and from books in local libraries. RESULTS: One-hundred twelve compounds of Eucommia ulmoides, including the main active constituents, lignans and iridoids, have been isolated and identified. In vitro and in vivo studies indicated that monomer compounds and extracts from Eucommia ulmoides possess wide-ranging pharmacological actions, especially in treating hypertension, hyperlipemia, diabetes, obesity, sexual dysfunction, osteoporosis, Alzheimer's disease, aging, lupus-like syndrome, and immunoregulation. CONCLUSIONS: Eucommia ulmoides has been used as a source of traditional medicine and as a beneficial health food. Phytochemical and pharmacological studies of Eucommia ulmoides have received much interest, and extracts and active compounds continue to be isolated and proven to exert various effects. Further toxicity and clinical studies are warranted to establish more detailed data on crude extracts and pure compounds, enabling more convenient preparations for patients. Therefore, this review on the ethnopharmacology, phytochemistry, biological activities, and toxicity of Eucommia ulmoides will provide helpful data for further studies as well as the commercial exploitation of this traditional medicine.

Norms of vagal nerve activity, indexed by Heart Rate Variability, in cancer patients.

Recent research has begun to show the role of the activity of the vagus nerve in cancer prognosis. However, it remains unknown whether cancer severity can impair vagal nerve activity. This study combined data (N=657) of five different cancers (colorectal, pancreas, prostate, lung and ovarian) concerning patients' Heart Rate Variability (HRV), a vagal nerve activity index. These data were compared to HRV levels of a healthy sample in another study. In addition, we examined the moderating effects of age, gender and cancer stage on HRV. The mean HRV of the cancer patients sample was significantly lower (HRV=22 ms) compared to the healthy sample (HRV=50 ms) (p<0.000001). While age and gender did not significantly affect HRV, cancer patients with advanced stages had significantly lower HRV than those with early stages (p=0.011). A possible bi-directional relation between cancer and vagal nerve activity is discussed. These findings are of importance for prognostication since they provide researchers and clinicians with expected values of vagal nerve activity in cancer patients.