A comprehensive review of heart rate variability as an indicator in the regulation of the autonomic nervous system by acupuncture:a bibliometric analysis

This study sought to conduct a bibliometric analysis of acupuncture studies focusing on heart rate variability(HRV)and to investigate the correlation between various acupoints and their effects on HRV by utilizing association rule mining and network analysis.A total of 536 publications on the topic of acupuncture studies based on HRV.The disease keyword analysis revealed that HRV-related acupuncture studies were mainly related to pain,inflammation,emotional disorders,gastrointestinal function,and hypertension.A separate analysis was conducted on acupuncture prescriptions,and Neiguan(PC6)and Zusanli(ST36)were the most frequently used acupoints.The core acupoints for HRV regulation were identified as PC6,ST36,Shenmen(HT7),Hegu(LI4),Sanyinjiao(SP6),Jianshi(PC5),Taichong(LR3),Quchi(LI11),Guanyuan(CV4),Baihui(GV20),and Taixi(KI3).Additionally,the research encompassed 46 reports on acupuncture animal experiments conducted on HRV,with ST36 being the most frequently utilized acupoint.The research presented in this study offers valuable insights into the global research trend and hotspots in acupuncture-based HRV studies,as well as identifying frequently used combinations of acupoints.The findings may be helpful for further research in this field and provide valuable information about the potential use of acupuncture for improving HRV in both humans and animals.

Sympathetic nervous system activation and heart failure:Current state of evidence and the pathophysiology in the light of novel biomarkers

Heart failure(HF)is a complex clinical syndrome characterized by the activation of at least several neurohumoral pathways that have a common role in maintaining cardiac output and adequate perfusion pressure of target organs and tissues.The sympathetic nervous system(SNS)is upregulated in HF as evident in dysfunctional baroreceptor and chemoreceptor reflexes,circulating and neuronal catecholamine spillover,attenuated parasympathetic response,and augmented sympathetic outflow to the heart,kidneys and skeletal muscles.When these sympathoexcitatory effects on the cardiovascular system are sustained chronically they initiate the vicious circle of HF progression and become associated with cardiomyocyte apoptosis,maladaptive ventricular and vascular remodeling,arrhythmogenesis,and poor prognosis in patients with HF.These detrimental effects of SNS activity on outcomes in HF warrant adequate diagnostic and treatment modalities.Therefore,this review summarizes basic physiological concepts about the interaction of SNS with the cardiovascular system and highlights key pathophysiological mechanisms of SNS derangement in HF.Finally,special emphasis in this review is placed on the integrative and up-to-date overview of diagnostic modalities such as SNS imaging methods and novel laboratory biomarkers that could aid in the assessment of the degree of SNS activation and provide reliable prognostic information among patients with HF.

Assessment of the autonomic nervous system is an appropriate biological marker for the well-being in erectile dysfunction

Aim： To investigate whether the autonomic nervous system （ANS） components are suitable biological markers for representing well-being in patients with erectile dysfunction （ED）. Methods： The present study included 74 male patients who had applied for check-ups in the cardiology outpatient clinic at Kirikkale University （Kirikkale, Turkey） and who had been diagnosed as having hyperlipidemia. Of these patients, 26 had an additional diagnosis of ED and made up the patient group. The remaining 48 patients formed the control group. Well-being was assessed with shortform 36 （SF-36）. The International Index of Erectile Function （IIEF） was used as a measure of libido and erectile function. Quantitative assessment of the ANS was made based on the analysis of heart rate variability by means of 24-h holter monitorization. Results： Comparisons between the ED and control groups showed significant differences only in energy scale of SF-36. The ED group also had significantly higher values of sympathetic activity. Except for the general health score of SF-36, which was found to be correlated with parasympathetic activity only in ED group, there were similar correlation patterns within the groups. Although well-being and sympathetic activity were correlated negatively, parasympathetic activity and well-being were correlated positively. Conclusion： Quantitative assessment of the ANS by heart rate variability analysis might be a suitable marker for well-being of patients with ED.

Effect of Autonomic Nervous System on the Transmural Dispersion of Ventricular Repolarization in Intact Canine

The effect of the autonomic nerves on the transmural dispersion of ventricular repolarization in intact canine was investigated. By using the monophasic action potential (MAP) recording technique, monophasic action potentials (MAPs) of the epicardium (Epi), midmyocardium (Mid) and endocardium (Endo) were recorded simultaneously by specially designed plunge needle electrodes at the left ventricular free wall in 12 open chest dogs. MAPD 90 and transmural dispersion of repolarization among three myocardial layers as well as the incidence of the EAD before autonomic nervous stimulation and during autonomic nervous stimulation were compared. The results showed that the MAPD 90 of Epi, Mid and Endo before autonomic nervous stimulation were 278±11 ms, 316±16 ms and 270±12 ms respectively, the MAPD 90 of Mid was significantly longer than that of Epi or Endo ( P <0.01). MAPD 90 of Epi, Mid and Endo were shortened by 19±4 ms, 45±6 ms, 18±3 ms respectively during sympathetic stimulation. Compared with that of the control, the transmural dispersion of repolarization during sympathetic stimulation was shortened from 44±4 ms to 15±3 ms ( P <0.01), but early afterdepolarizations were elicited in the Mid of 5 dogs (41 %) during sympathetic stimulation. Parasympathetic stimulation did not significantly affect the MAPD 90 in the three layers. It is concluded that there is the transmural dispersion of ventricular repolarization in intact canine. Sympathetic stimulation can reduce transmural dispersion of repolarization, but it can produce early afterdepolarizations in the Mid. Parasympathetic stimulation does not significantly affect the transmural dispersion of ventricular repolarization.

Experimental Study of the Effect of Autonomic Nervous System on the Transmural Dispersion of Ventricular Repolarization under Acute Myocardial Ischemia in Vivo

The effect of the autonomic nerves on the transmural dispersion of ventricular repolarization(TDR)under acute myocardial ischemia in intact canine was investigated.Using the monophasic action potential(MAP)recording technique,MAPs of the epicardium(Epi),midmyocardium(Mid)and endocardium(Endo)were recorded simultaneously by specially designed plunge-needle electrodes at the left ventricular free wall under acute myocardial ischemia in 12 open-chest dogs.MAPD 90 and TDR among three myocardial layers as well as the incidence of the early afterdepolarization(EAD)before autonomic nervous stimulation and during autonomic nervous stimulation were compared.It was found that 10 min after acute myocardial ischemia,TDR was increased from 55±8 ms to 86±15 ms during sympathetic stimulation(P<0.01).The TDR(53±9 ms)during parasympathetic stimulation was not significantly different from that of the control(55±8 ms)(P>0.05).The EAD was elicited in the Mid of 2 dogs(16%)10 min after acute myocardial ischemia,but the EAD were elicited in the Mid of 7 dogs(58%)during sympathetic stimulation(P<0.01).It was concluded that:(1)Sympathetic stimulation can increase the transmural dispersion of repolari-zation and induce early afterdepolarizations in the Mid under acute myocardial ischemia,which provide the opportunity for the ventricular arrhythmia developing;(2)Parasympathetic stimulation has no significant effect on the transmural dispersion of repolarization under myocardial ischemia.

Changes in Autonomic Nervous System Activity and Mood of Healthy People after Mindfulness Art Therapy Short Version

The aim of this study was to investigate changes in autonomic nervous system (ANS) activity and mood caused by Mindfulness Art Therapy Short version (MATS). The participants were 20 Japanese college students who were separated into high and low risk groups based on the median score of the General Health Questionnaire (GHQ). MATS consisted of mindfulness exercise and making of art in one session. ANS activity (TP: total energy, LF/HF: sympathetic nervous, HF: parasympathetic nervous system, LF: both sympathetic and parasympathetic) and mood (TA: tension arousal, EA: energy arousal) were measured psychologically before and after MATS. In the high risk group, TP significantly decreased and LF, HF, and LF/HF did not change significantly;while TA significantly decreased and EA significantly increased. In the low risk group, TP and LF significantly increased and HF and LF/HF did not change significantly;while TA significantly decreased and EA showed a non-significant increase. These results suggest that MATS affects the ANS differently for participants with different states of mental health, and particularly promotes activity in low-risk participants. Psychologically, MATS decreased tension or anxiety and increased energy. These findings justify further use of this therapy.

Effect of 528 Hz Music on the Endocrine System and Autonomic Nervous System

This study examined the stress-reducing effect on the endocrine system and the autonomic nervous system of music with a frequency of 528 Hz, which has recently attracted attention as a “healing” type of music. Nine healthy participants (one man and eight women, aged 26 - 37 years) listened to 528 Hz and standard 440 Hz music on separate days. We measured salivary biomarkers of stress (cortisol, chromogranin A, and oxytocin) before and after exposure to music, and continuously recorded the activity of the autonomic nervous system. The Profile of Mood State, 2nd edition, was also administered as a subjective indicator of stress. In the 528 Hz condition, mean levels of cortisol significantly decreased, chromogranin A tended to decrease, and oxytocin significantly increased after music exposure. However, no significant change was observed in any salivary biomarkers in the 440 Hz condition. The ratio of low frequency to high frequency autonomic nervous system activity significantly decreased after exposure to both types of music, and the coefficient of variation of R-R intervals also significantly decreased, but only after exposure to 528 Hz music. Tension-anxiety and Total Mood Disturbance scores were significantly reduced after exposure to 528 Hz music, while there was no significant difference following 440 Hz music. These results suggest that the influence of music on the autonomic nervous system and endocrine system varies depending on the frequency of the music, and furthermore, that 528 Hz music has an especially strong stress-reducing effect, even following only five minutes of exposure.

Can the early bird catch the worm? Effects of early rising on leukocyte subsets via modification of autonomic nervous system and the effect on glucose levels

The importance of sleep has been described in proverbs such as “the early bird catches the worm”. However, there are few scientific reports on the effects of early rising. Therefore, early risers (Group E) and late risers (Group L) were compared and the number and ratio of leukocytes, body temperature, glucose and its associated hormones were studied. Furthermore, each group was divided into two groups by the duration of sleep and the following four groups were compared: early risers with short sleep (Group E-S);early risers with long sleep (Group E-L);late risers with short sleep (Group L-S);and late risers with long sleep (Group L-L). Then, compared with Group L, Group E showed lower numbers and ratio of granulocytes and a higher ratio of lymphocytes showing parasympathetic nerve dominance. Group E showed higher levels of glucose and its related hormones than Group L, indicating sympathetic nerve dominance. Compared with Groups E-S and L-S, Groups E-L and L-L showed lower glucose and cortisol levels, respectively. These results indicated that early rising might affect leukocyte subsets, and adequate duration of sleep could decrease levels of glucose via modification of the autonomic nervous system.

Nadi Yantra: a robust system design to capture the signals from the radial artery for assessment of the autonomic nervous system non-invasively

Ayurvedic and other alternative medical practi-tioners throughout the world have been using pulse diagnosis to detect disease and the organ at distress by feeling the palpations at three close yet precise positions of the radial artery. This paper presents a robust electro-mechanical system, ‘Nadi Yantra’ which uses piezoelectric based pressure sensors to capture the signals from the radial artery. Morphology of the waveforms obtained from our system concurs with standard physiological arterial signals. Reproducibility and stability of the system has been verified. Signal processing techniques were applied to obtain features such as amplitude, power spectral density, bandpower and spectral centroid to reflect variations in signals from the three channels. Further, wavelet based techniques were used to process the pressure signals and percussion peaks were identified. The interval between the percussion peaks was used to calculate Heart Rate Varibility (HRV), a useful tool for assessing the status of the autonomic nervous system of the human body non-invasively. Time domain indices were calculated from direct measurement of peak-peak (PP) intervals and from differences between the PP intervals. Frequency domain indices such as very low frequency (VLF) power, low frequency (LF) power, high frequency (HF) power, LF/HF ratio were also calculated. Thereafter, nonlinear Poincare analysis was carried out. A map of consecutive PP intervals was fitted to an ellipse using least squares method. Results from 7 datasets are depicted in this paper. A novel pressure pulse recording instrument is deve loped for the objective assessment of the ancient sci-ence of pulse diagnosis. The features calculated using multi resolution wavelet analysis show potential in the evaluation of the autonomic nervous system of the human body.

The Influence of a Posture on the Autonomic Nervous System and Stress Hormones in Saliva

Humans and animals give several impressions to their recipients with their postures. In this study, the influence of postures on a body was examined through the perspective of the endocrine system and the autonomic nervous system. The subjects were 18 healthy adults (7 males and 11 females). A slouching posture like arching back was defined as a low power pose (LP), and a posture straightening back and throwing out chest is defined as a high power pose (HP). Starting at rest, the subjects took LP posture and changed to HP posture, and their autonomic nervous functions were measured and their saliva was collected before and after taking each posture. In taking LP posture, the decrease of the parasympathetic nervous activity, the increase of the pathetic nervous activity and the increase of chromogranin A in saliva were observed. The increase of the autonomic nervous activity, and the decrease of chromogranin A which had been increased by taking LP posture were observed by taking HP posture. There was no influence on cortisol by taking either of the postures. This study suggested that bad postures such as curving back affected stress reactions through the perspective of the endocrine system and the automatic nervous system.

Effect of Endurance Training on the Autonomic Nervous System Function of Young Male

In this study, healthy young males were randomized into groups with moderate intensity training (n = 24), high intensity training (n = 24) and utmost intensity training (n = 24). At the end of 8-week training period, HRV measurements demonstrated a marked increase of RMSSD (P = 0.003), PNN50 (P = 0.002), HF (P = 0.002), SDNN (P = 0.002) and LF (P = 0.003) in the moderate intensity group and a decreasing tendency in LFn and LF/HF;however, in the utmost intensity group HFn (P = 0.012) decreased prominently while its LF (P = 0.032), LFn (P = 0.039) and LF/HF (P = 0.015) increased significantly. Nevertheless marked changes were not found in the above indexes of the high intensity group. While resting HR of the three groups declined significantly at the end of 8 weeks (P was 0.001, 0.0001 and 0.001 respectively);RMSSD, PNN50, HF, LF and SDNN were significantly higher in the moderate intensity group than in the other two groups (P P = 0.012) was significantly lower but its LFn and LF/HF were markedly higher (P was 0.025 and 0.015 respectively);LF/HF of both the high and utmost intensity group was significantly higher (P was 0.033 and 0.037 respectively). Despite a significant reduction of plasma NE in all the three groups at the end of 8-week training period (P was 0.016, 0, 0.031 respectively), plasma NE level of moderate and high intensity group was much lower than that of the utmost intensity group (P was 0.001, 0 respectively). Utmost and moderate endurance training results in altered sympathetic and parasympathetic balance towards sympathetic dominance and parasympathetic dominance respectively;whereas high intensity endurance training almost has no effect on ANS function. CPT and HUTT reveal the potential danger posed by utmost intensity endurance training.

The Effects of Green Kiwifruit Ingestion on Digestive Health, Blood Flow, Skin Health, and the Autonomic Nervous System

We aimed to assess the impact of consuming two Zespri Hayward green kiwifruit a day on 11 healthy women subjects over a period of 4 consecutive weeks. We analyzed the effects of kiwifruit consumption on intestinal, abdominal, and bowel movement related discomfort, bowel movement frequency, peripheral blood flow, skin health, and autonomic nervous system activity. This study was a randomized control trial, consisting of a four-week intervention period. Participants were divided to ensure equal age distributions and then randomly placed into two intervention groups: a kiwifruit consumption group (n = 11) and a control group (no kiwifruit consumption) (n = 5). The kiwifruit consumption group was instructed to consume two kiwifruit a day during the 4-week intervention period, while subjects in the control group were instructed not to consume kiwifruit for the duration of the study. Besides a restriction from eating yogurt and other fruits, subjects were requested to eat their meals as per usual. The results of this study showed a significant decrease in intestinal, abdominal, and bowel movement discomfort, and a significant increase in bowel movement frequency, at 4 weeks of kiwifruit consumption compared to before consumption. In addition, subjects in the kiwifruit consumption group experienced a significant increase in blood flow, particularly in the index and middle finger at 2 and 4 weeks of kiwifruit consumption. Furthermore, subjects in the kiwifruit consumption group experienced a significant increase in skin brightness at 4 weeks of kiwifruit consumption compared to before consumption. The results of this study suggest that kiwifruit appears to be a delicious and safe option for intestinal, abdominal, and bowel movement discomfort interventions for healthy women. In addition, kiwifruit may aid in increasing bowel movement frequency, peripheral blood flow, and brightness of skin among healthy women as well.

The Influence of Behavioral and Psychological Symptoms of Dementia on the Autonomic Nervous System

Stress is one of the most potent of many factors that can cause expression of behavioral and psychological symptoms of dementia (BPSD). Stress can also increase autonomic nervous activity. This study aimed to examine the relationships between BPSD and autonomic function in the elderly with dementia. We recruited 35 participants diagnosed with dementia from nearby geriatric health service facilities. The Neuropsychiatric Inventory was used for the evaluation of BPSD, and a TAS 9 VIEW (manufactured by YKC) was used for the heart rate variability analysis to measure autonomic nervous system activity. We constructed a model in which the autonomic nervous system comprised a category and performed a structural equation modeling analysis to calculate the standardization coefficient and correlation coefficient for each factor. The results showed that the influence of BPSD resulted in suppression of sympathetic and enhancement of parasympathetic nervous system activity.

The Effect of Brief, Low-Intensity Stretching Gymnastics on Autonomic Nervous System Activity and Cognitive Function

Purpose: Stretching exercise and gymnastics both have beneficial effects, such as improvement of autonomic nervous system activity and mood. Additionally, studies on the effects of exercise on cognitive function have been conducted covering a wide range of age groups and have attracted much attention. However, conventional studies have set up programs with implementation times of 20 to 30 minutes. Therefore, shorter stretching programs are needed in order to fit them more easily into one’s free time. We examined the effects of a short 7-minute stretching gymnastics regime on the autonomic nervous system activity and cognitive function in 21 healthy participants. Methods: In this study, the participants performed a 10-minute cognitive task, followed by either Stretch Well Gymnastics, Stretch Band Gymnastics, or Radio Gymnastics sessions on different days. The participants then performed the cognitive task again. Heart rate was measured continuously throughout the experiment and we analyzed the heart rate variability. The cognitive tasks completed by all of the participants were evaluated for inhibitory control and cognitive flexibility. Results: A significant increase was shown in the sympathetic nerve activity during the Stretch Well Gymnastics, compared to the Radio Gymnastics and Stretch Band Gymnastics. Parasympathetic nerve levels were significantly increased after the gymnastics, compared to during the gymnastics, although there were no significant differences between any of the tasks. Additionally, in both the Stroop task and the number-Letter task, reaction times were faster in all of the sessions. In particular, the Stroop task showed the highest values for the Radio Gymnastics sessions, with marginally significantly lower scores for the Stretch Well Gymnastics sessions. Conclusion: The results showed that these heart rate variability responses supported the effects of autonomic activity associated with conventional low-intensity exercise. Additionally, stretching gymnastics for less than 10 minutes showed a positive effect on inhibitory function and cognitive flexibility.

Stress prevention by modulation of autonomic nervous system (heart rate variability): A preliminary study using transcranial direct current stimulation

Introduction: Transcranial Direct Current Stimulation (tDCS) is a non-invasive, technique for brain stimulation. Anodal stimulation causes neuronal depolarisation and long-term potentiation, while cathodal stimulation causes hyperpolarisation and long-term depression. Stressors are associated with an increase in sympathetic cardiac control, a decrease in parasympathetic control, or both. Associated with these reactions is a frequently reported increase in Low Frequency (LF) Heart Rate Variability (HRV), a decrease in High Frequency (HF) power, and/or an increase in the LF/HF ratio. Objectives and aims: The present work aims to explore the tDCS potential in the modulation of the Autonomic Nervous System (ANS), through indirect stimulation of Anterior Cingulate Cortex (ACC). Methods: Two subjects, a 39 year old female and a 49 year old male, gave informed consent. Saline soaked synthetic sponges involving two, thick, metalic (stainless steel) rectangles, with an area of 25 cm2 each have been used as electrodes, connected to Iomed Phoresor II Auto device. It has been delivered a 2 mA current, for 20 minutes, over the left Dorsolateral Prefrontal Cortex (DLPFC) (Anode). Spectrum analysis (cStress software) of HRV has been performed before and after tDCS administration. Results: The female/male subject results of LF power, HF power and LF/HF ratio, before tDCS administration, were, respectively: 50.1 nu/60 nu, 46.1 nu/21.7 nu and 1.087/2.771;and, after tDCS administration, respectively: 33.5 nu/52.7 nu, 47.6 nu/ 22.8 nu and 0.704/2.312. Conclusions: tDCS over the left DLPFC (left ACC) increased parasympathetic activity and decreased sympathetic activity, suggesting the importance of tDCS in the management of stress-related disorders.

Relationship between autonomic nervous system function and acute mountain sickness

Objective: To elucidate the role of the autonomic nervous system (ANS) in acute mountain sickness (AMS) during the initial phase at acute high-altitude exposure. Methods: Ninety-nine healthy sea-level residents rapidly ascended to Tibet plateau (3 675 m altitude) by airplane from Chengdu plain (560 m altitude). ANS function was tested in plain and day 2–4 in Tibet by heart rate variability (HRV), cold pressor test (CPT). AMS was evaluated by clinic symptomatic scores. All subjects were divided into non-AMS group (57, scores≤4) and AMS group (42, scores>4). Results: Compared with non-AMS group, AMS group had higher standard deviation of normal to normal intervals (SDNN), root mean square of delta RR (rMSSD), low-frequency (LF) power, and normalized low-frequency (LFnu) power in plain (P<0.05). After arrival at 3 675 m altitude, AMS group had greater reduction in percentage of delta RR>50 ms(PNN50), rMSSD (P<0.01) and SDNN, LF, total power (TP) (P<0.05). Although no significant differences in the increase of SP and DP during CPT were found between 2 groups in plain, the SP increase during CPT of AMS group was less than non-AMS group (P<0.05) at 3 675 m altitude. AMS symptomatic scores was not only positively correlated with SDNN, rMSSD, LF/HF in plain (P<0.05), but also negatively correlated with HFnu in plain (P<0.05). Conclusion: During the initial high altitude exposure, ANS modulation is generally blunted, but the relatively predominant sympathetic control is enhanced, and this characteristic change of ANS function is positively correlated with the development of AMS.

Positive effects of music therapist's selected auditory stimulation on the autonomic nervous system of patients with disorder of consciousness: a randomized controlled trial

The current randomized controlled trial was performed at the China Rehabilitation Science Institute, China to test the hypothesis that musical auditory stimulation has positive effects on the autonomic nervous system of patients with disorder of consciousness.Although past studies have recommended that patients with disorder of consciousness listen to patient-preferred music, this practice is not universally accepted by researchers.Twenty patients with severe disorder of consciousness listened to either therapist-selected(n = 10, 6 males and 4 females;43.33 ± 18.76 years old) or patient-preferred(n = 10, 5 males and 5 females, 48.83 ± 18.79 years old) musical therapy, 30 minutes/day, 5 times/week for 6 weeks.The results showed no obvious differences in heart rate variability-related parameters including heart rate, standard deviation of normal-to-normal R-R intervals, and the root-mean-square of successive heartbeat interval differences of successive heartbeat intervals between the two groups of patients.However, percentage of differences exceeding 50 ms between adjacent normal number of intervals, low-frequency power/high-frequency power, high-frequency power norm, low-frequency power norm, and total power were higher in patients receiving therapist-selected music than in patients receiving their own preferred music.In contrast, this relationship was reversed for the high-frequency power and very-low-frequency band.These results suggest that compared with preferred musical stimulation, therapist-selected musical stimulation resulted in higher interactive activity of the autonomic nervous system.Therefore, therapist-selected musical stimulation should be used to arouse the autonomic nervous system of patients with disorder of consciousness.This study was approved by the Institutional Ethics Committee of China Rehabilitation Research Center, China(approval No.2018-022-1) on March 12, 2018 and registered with the Chinese Clinical Trial Registry(registration number Chi CTR1800017809) on August 15, 2018.

The relationship between sleep condition and autonomic nervous function in women in their 70s with type 2 diabetes mellitus

The aim of this study was to determine the relationship between sleep condition and autonomic nervous function of women in their 70s with type 2 diabetes mellitus by analyzing the activity counts (AC) on actigraphs and heart rate variability (HRV). Ten healthy women in their 30s to 40s as control and four women patients with type 2 diabetes in their 70s wore the electrocardiograph and an actigraph for 24 hours while keeping a diary of activities, including their sleep and food intake. The Pittsburgh Sleep Quality Index was used to assess subjective sleep conditions. The subjective sleeping results were significantly correlated with those measured by the AC and HRV. However, AC and HRV correlation pattern showed different activity in the patients with type 2 diabetes mellitus. The quality of sleep of those with chronic diabetes was not good even if their HbA1c was well controlled. Furthermore, their automatic nervous function was different from the control group. The sleeping hours of patients with type 2 diabetes were shorter or longer than those of healthy women. Ultimately, this study maintains that it is important to examine automatic nervous functions using objective examination index during the early stage of diabetes mellitus.

Analogs of microgravity: the function of Schlemm's canal, intraocular pressure and autonomic nervous during the head-down tilt test in healthy subjects

AIM:To evaluate the ocular outcomes and to elucidate possible mechanisms underlying intraocular pressure(IOP)change following the head-down tilt(HDT)test.METHODS:The study included 21 participants at the Department of Ophthalmology of Tongji Hospital.Subjects received the test of I-care tonometry,enhanced depth imaging optical coherence tomography and heart rate variability(HRV)analysis before and after 15 min HDT test.The lumen area of Schlemm’s canal(SCAR),IOP,HRV were calculated.RESULTS:IOP increased significantly after 20°head down position from 14.0±3.0 to 17.0±3.3 mm Hg(P<0.001).SCAR decreased from 13449.0±5454.9μm^(2) at sitting condition to 9576.6±4130.9μm^(2) post 15 min HDT test.High frequency(HF)indices increased significantly from 1462±865 Hz at baseline to 2128±824 Hz.Heart rate(HR)decreased significantly from 76±11.48 to 70±11.52 bpm after the HDT.The linear regression analysis showed that the difference of HF and SCAR significantly correlated with each other during the HDT(R^(2)=20%,P=0.04).CONCLUSION:These outcomes perform the first evidence of the activation of autonomic nervous system of HDT may cause the collapse of Schlemm’s canal lumen,which in turn leading to the increased IOP.