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.

Quran memorisation and heart rate variability:How do they correlate?

BACKGROUND Heart rate variability(HRV)was shown to be affected by performing religious activities.AIM To examine the relationship between the level of Quran(the holy book of Muslims)memorisation and HRV among teenagers.METHODS This experimental study included 16 Tahfiz students and 16 non-Tahfiz students(n=32).The HRV was measured in three tasks:Recalling familiar verses,memorising new verses,and recalling the newly memorised verses of the Quran.HRV analysis was done using these parameters:Standard deviation of N-N(heartbeat peak)interval;low frequency(LF);high frequency(HF)and LF/HF ratio.RESULTS There were significant differences between tasks for all parameters(P<0.05).However,between the groups,only the LF/HF ratio had significant differences,with F=5.04,P<0.05.Pearson correlation showed a moderate positive correlation between the number of pages memorised and the LF/HF ratio(r=0.61,P<0.05).CONCLUSION Quran memorisation increased the HRV and our results suggested that this activity could be developed as an effective sympathovagal modulation training activity.

Assessment of autonomic function in untreated adult coeliac disease

AIM: Some recent studies showed that alteration of upper-gut motility in coeliac disease may be related to dysfunction of autonomic nervous system. The aim of our study was to investigate whether autonomic nervous system was altered in untreated and unselected coeliac disease patients.METHODS: We studied 8 untreated and consecutive coeliac disease patients (2 males and 6 females, age range 37±14.5 years). Histological evaluation of duodenal mucosa, anti-gliadin antibodies (AGA), antiendomysial antibodies (EMA) and anti-tTG antibodies and sorbitol H2 breath test were performed in all patients. Extrinsic autonomic neuropathy was assessed by the standardized measurement of cardiovascular reflexes (lying-to-standing,Valsalva manoeuvre, deep breathing, sustained handgrip).The results obtained were compared with a healthy,asymptomatic control group (6 males and 7females, age range 42.3±13.5 years).RESULTS: Coeliac patients exhibited a lower increase of PAS as a response to isometric effort, a reduction of spectral power LF as a response to clinostatic position,but without statistical significance. Also they showed a lower tolerance to orthostatic position, associated with a latent disequilibrium of sympathetic-vagal balance, a relative prevalence of parasympathetic component of the autonomic function. However, these results were not statistically significant when compared with control group(P = n.s.). And they were unchanged after 6 and 12 mo of gluten-free diet.CONCLUSION: This study failed to confirm a significant correlation between autonomic dysfunction and coeliac disease, yet we could not exclude a role of autonomic dysfunction in the genesis of systemic symptoms in some coeliacs.

Does heart rate variability correlate with long-term prognosis in myocardial infarction patients treated by early revascularization?

AIMTo assess the prevalence of depressed heart rate variability (HRV) after an acute myocardial infarction (MI), and to evaluate its prognostic significance in the present era of immediate reperfusion.METHODSTime-domain HRV (obtained from 24-h Holter recordings) was assessed in 326 patients (63.5 ± 12.1 years old; 80% males), two weeks after a complicated MI treated by early reperfusion: 208 ST-elevation myocardial infarction (STEMI) patients (in which reperfusion was successfully obtained within 6 h of symptoms in 94% of cases) and 118 non-ST-elevation myocardial infarction (NSTEMI) patients (percutaneous coronary intervention was performed within 24 h and successful in 73% of cases). Follow-up of the patients was performed via telephone interviews a median of 25 mo after the index event (95%CI of the mean 23.3-28.0). Primary end-point was occurrence of all-cause or cardiac death; secondary end-point was occurrence of major clinical events (MCE, defined as mortality or readmission for new MI, new revascularization, episodes of heart failure or stroke). Possible correlations between HRV parameters (mainly the standard deviation of all normal RR intervals, SDNN), clinical features (age, sex, type of MI, history of diabetes, left ventricle ejection fraction), angiographic characteristics (number of coronary arteries with critical stenoses, success and completeness of revascularization) and long-term outcomes were analysed.RESULTSMarkedly depressed HRV parameters were present in a relatively small percentage of patients: SDNN < 70 ms was found in 16% and SDNN < 50 ms in 4% of cases. No significant differences were present between STEMI and NSTEMI cases as regards to their distribution among quartiles of SDNN (χ2 =1.536, P = 0.674). Female sex and history of diabetes maintained a significant correlation with lower values of SDNN at multivariate Cox regression analysis (respectively: P = 0.008 and P = 0.008), while no correlation was found between depressed SDNN and history of previous MI (P = 0.999) or number of diseased coronary arteries (P = 0.428) or unsuccessful percutaneous coronary intervention (PCI) (P = 0.691). Patients with left ventricle ejection fraction (LVEF) < 40% presented more often SDNN values in the lowest quartile (P < 0.001). After > 2 years from infarction, a total of 10 patients (3.1%) were lost to follow-up. Overall incidence of MCE at follow-up was similar between STEMI and NSTEMI (P = 0.141), although all-cause and cardiac mortality were higher among NSTEMI cases (respectively: 14% vs 2%, P = 0.001; and 10% vs 1.5%, P = 0.001). The Kaplan-Meier survival curves for all-cause mortality and for cardiac deaths did not reveal significant differences between patients with SDNN in the lowest quartile and other quartiles of SDNN (respectively: P = 0.137 and P = 0.527). Also the MCE-free survival curves were similar between the group of patients with SDNN in the lowest quartile vs the patients of the other SDNN quartiles (P = 0.540), with no difference for STEMI (P = 0.180) or NSTEMI patients (P = 0.541). By the contrary, events-free survival was worse if patients presented with LVEF < 40% (P = 0.001).CONCLUSIONIn our group of patients with a recent complicated MI, abnormal autonomic parameters have been found with a prevalence that was similar for STEMI and NSTEMI cases, and substantially unchanged in comparison to what reported in the pre-primary-PCI era. Long-term outcomes did not correlate with level of depression of HRV parameters recorded in the subacute phase of the disease, both in STEMI and in NSTEMI patients. These results support lack of prognostic significance of traditional HRV parameters when immediate coronary reperfusion is utilised.

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.

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.

Changes of autonomic nervous system function in healthy young men during initial phase at acute high-altitude exposure

Objective: To investigate the changes of autonomic nervous system (ANS) function during the initial phase at acute high-altitude exposure. Methods: Ninety-nine healthy sea-level male residents were studied in Chengdu plain and then Tibet plateau. Heart rate variability (HRV), cold pressor test (CPT), resting heart rate (HR) and blood pressure (BP) were measured at baseline (560 m altitude) and in 2 to 4 d after arriving at Tibet plateau (3 675 m altitude) to assess the ANS function. Results: Compared with baseline, on day 2 in Tibet the standard deviation of normal to normal intervals (SDNN), high-frequency (HF) power, total power (TP), root mean square of delta RR (rMSSD), percentage of delta RR>50 ms (PNN50), normalized high-frequency (HFnu) and fractal dimension (FD) decreased significantly (SDNN, HF, TP P<0.01, rMSSD, PNN50, HFnu, FD P<0.05), while the normalized low-frequency (LFnu) and LF/HF increased significantly (P<0.01). During day 3–4 in Tibet, SDNN, rMSSD, HF, TP and HFnu tended to rebound while LFnu and LF/HF decreased towards baseline day by day. In addition, in Tibet the increase in systolic pressure (SP) and diastolic pressure (DP) during CPT decreased significantly (P<0.01, 0.05), but resting HR increased compared with baseline (P<0.01). Conclusion: ANS modulation is generally blunted, and the relatively predominant sympathetic control is enhanced originally, then it reverts to the sea level states gradually during the initial days of acute high-altitude exposure.

A Study into Blood Flow, Heart Rate Variability, and Body Surface Temperature While Listening to Music

In this study we examined the relaxing effects of listening to music on a total of 12 women aged from their 20s to their 40s by measuring their blood flow, heart rate variability, and their body surface temperature. As a result, We found that there was a tendency for the volume of blood flow to the fingertips to significantly increase when listening to classical music, but there was a variety of changes in blood flow between each age group for healing music and J-Pop music. When measuring heart rate it was found that the LF/HF value, which is an index for the autonomic nervous system which shows tension and stress, fell significantly when listening to each type of music. Lastly, there was a trend for body surface temperature to rise when listening to classical or healing music, a rise which was particularly significant when listening to healing music. This study shows that a relaxing effect can be expected for all indices when listening to classical music. However, for healing music and J-Pop, personal musical preferences seemed to have an effect and the results were varied.

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.

Measurement and Evaluation of the Autonomic Nervous Function in Daily Life

We developed a smart-phone based system to measure the activities of autonomic nervous system during everyday life. Using commonly marketed smart phones, by touching your fingertips on the phone’s camera over a short time of about 30 seconds, it will detect changes in the brightness of the blood flow and in turn analyze your heart rate variability. By using this system, about 100,000 cases were measured and from this large amount of data regarding heart rate variability, we evaluated the autonomic nervous function in their daily life. As a result, for the correlation between autonomic nervous system and age, we found that as the increase of age, the total power becomes decreased and the sympathetic nervous system tends to increase between thirties and fifties. For the correlation between autonomic nervous system and BMI (Body Mass Index), it is found that in general, the higher the BMI, the lower the total power and the stronger the sympathetic nervous system. In other words, people who are fat are lower about the total power and stronger about the sympathetic nervous system. In addition, for the correlation between autonomic nervous system and one day life, it is found that total power and sympathetic function tend to increase, while as evening approaches, sympathetic function tends to become suppressed.

Modeling of Heart Rate Variability Using Time-Frequency Representations

The heart rate variability signal is highly correlated with the respiration even at high workload exercise.It is also known that this phenomenon still exists during increasing exercise.In the current study,we managed to model this correlation during increasing exercise using the time varying integral pulse frequency modulation(TVIPFM)model that relates the mechanical modulation(MM)to the respiration and the cardiac rhythm.This modulation of the autonomic nervous system(ANS)is able to simultaneously decrease sympathetic and increase parasympathetic activity.The TVIPFM model takes into consideration the effect of the increasing exercise test,where the effect of a time-varying threshold on the heart period is studied.Our motivation is to analyze the heart rate variability(HRV)acquired by time varying integral pulse frequency modulation using time frequency representations.The estimated autonomic nervous system(ANS)modulating signal is filtered throughout the respiration using a time varying filtering,during exercise stress testing.And after summing power of the filtered signal,we compare the power of the filtered modulation of the ANS obtained with different time frequency representations:smoothed pseudo Wigner–Ville representation,spectrogram and their reassignments.After that,we used a student t-test p<0.01 to compare the power of heart rate variability in the frequency band of respiration and elsewhere.

Long-Term Monitoring and Analysis of Age-Related Changes on Autonomic Nervous Function

This study used a small wearable heart rate sensor to monitor the daily autonomic function of 600 subjects from across all age groups over a prolonged period of time. The results indicated that the LF/HF ratio (Heart Rate Variability, LF: frequencies between 0.04 Hz - 0.15 Hz, HF: frequencies between 0.15 Hz - 0.4 Hz) an indicator of balance in the autonomic nervous system, tended to peak for subjects in their 40’s and decline thereafter. This conceivably may be partially due to the causes for concern and stress changing and/or declining for the group aged 50-plus. A decline in diurnal variation of autonomic nervous activity was also exhibited in subjects aged 50 and up, showing a tendency for decline in the function of rising sympathetic nerve activity particularly in the morning. It is conceivable that this stems from a decline in the responsiveness of the autonomic nervous system. Subjects in the 50-plus group furthermore exhibited a tendency for declining variation in autonomic nervous activity between sleeping and waking hours. This phenomenon was consistent with the tendency for there to be a rise in wake after sleep onset coupled with a decline in slow-wave sleep in middle- to old-age.

Evaluation with Heart Rate Variability for the Treatment Effect of Aminophylline in Patients with Bradycardia after Cervical Spinal Cord Injury: A Preliminary Study

After cervical spinal cord injury (SCI), the autonomic nervous system (ANS) becomes impaired and then, bradycardia can develop. In view of this, we performed to prescribe aminophylline as pharmacotherapy for bradycardia. The study population consisted of 36 patients with cervical SCI. Bradycardia developed in 20 patients (55.6%), of these patients, 8 showed spontaneous recovery. Twelve patients had persistent bradycardia, therefore, aminophylline was administered at 0.5 mg/kg/hr by intravenous infusion. Their average heart rate increased within 24 hours after the start of infusion. In heart rate variability analysis for 7 preliminarily selected patients, the spectral waveforms of “oligowave type” indicating ANS impairment tended to appear in relatively early phase after injury (i.e., 2 days to 2 weeks after injury), whereas “normal type” was observed in the late phase (i.e., at 4 weeks). “Sympathetic block type” was observed throughout the follow-up period (2 days to 4 weeks). “Sympathetic block type” was also observed in a non-bradycardic patient on day 2. These results underscore the importance of treating ANS impairment with aminophylline while keeping in mind that bradycardia can occur even in post-SCI patients without clinical manifestations.

On Human Autonomic Nervous Activity Related to Behavior, Daily and Regional Changes Based on Big Data Measurement via Smartphone

This research uses a large amount of autonomic nervous system data (approximately 100,000 entries) to investigate the relationship between human autonomic nervous activity and behaviors, daily and regional changes. Data were measured via a heart rate variability analysis system that utilizes the camera of smartphones. This system was developed by the authors during previous research. The relations between autonomic nervous system and behaviors, total power and sympathetic nervous activity were found to rise after waking, while during leisure time, the total power rises and sympathetic nervous activity is inhibited. Concerning the relationship between autonomic nervous system and day of the week, it was found that total power decreases from the middle through the latter part of the week (namely, Wednesday, Thursday, and Friday), while it rises on Saturday, while the sympathetic nervous activity is suppressed on Saturday. Regarding the relationship between autonomic nervous system and region, it was found that total power is lower in the Kanto region of Japan than in others. This study also shows statistical proof (using a large amount of measurement data) to ideas held by the public for years. Thus, the data can be considered meaningful to the society, and the authors hope that it helps to improve work-life balance.

On Human Autonomic Nervous Activity Related to Weather Conditions Based on Big Data Measurement via Smartphone

This research uses our previously-developed smartphone camera-based heart rate change analysis system to survey the correlation between weather patterns and the autonomic nervous activity across a big data set of approximately 200,000 entries. The results showed a trend in which a significant decrease was seen in sympathetic nervous activity in both males and females—the higher the temperature. In addition, a significant increase was seen in the sympathetic nervous system in both males and females—the higher the atmospheric pressure. Lastly, a significant decrease was seen in the sympathetic nervous system in both males and females—the more precipitation there was. These results accord with prior research and with human biological phenomena, and we were able to use a data set of approximately 200,000 entries to statistically demonstrate our hypothesis. We believe this represents a valuable set of reference data for use in the health care.

The association of salivary alpha-amylase, heart rate variability, and psychological stress on objectively measured sleep behaviors among college students

Objective:This study aimed to evaluate sleep behaviors among college students,to assess salivary alpha-amylase(sAA)and heart rate variability(HRV)in association with stress,and to investigate sleep-related factors including sAA,HRV,and stress among them.Methods:Saliva samples for sAA assessment and HRV measurements in the supine position were taken between 3 PM and 6 PM.The level of prolonged psychological stress for the previous week was evaluated using the Korean version of the Global Assessment of Recent Stress(GARS-K),and sleep behaviors were assessed using an actigraphy device.Results:A total of 86 healthy college students participated in this study.Sleep behaviors of the college students were not good,with 84%sleep efficiency(SE)and 62.7 min wake after sleep onset(WASO).The average sAA level was 65.8 U/mL in the participants.Although neither the sAA level nor HRV indices were significantly correlated with prolonged psychological stress,decreased normalized high frequency(nHF)on HRV was independently associated with a higher level of stress when adjusted for age and sex.Higher stress(r=-0.276,P=0.011)and lower sAA(r=0.266,P=0.030)had significant correlations with shorter time in bed;however,it was sAA that was independently associated with time in bed(β=0.244,p=0.044).Decreased nHF(β=0.245,P=0.027)and higher body mass index(BMI)(β=-0.224,P=0.043)were independently related to and poorer SE.Conclusions:Poor sleep behaviors were associated with decreased parasympathetic activity,a physiological change to psychological stress,rather than with psychological stress itself among college students.Thus,sAA and HRV should be considered as significant factors for impaired sleep behaviors in relation to psychological stress.

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.

Characteristic Autonomic Nervous Activity of Institutionalized Elders with Dementia

This study clarified the characteristic autonomic nervous activity of institutionalized elders diagnosed with dementia using Hasegawa’s Dementia Scale-Revised. Twenty-six healthy adult persons (HPs) in their 20 s - 40 s met the inclusion criteria, and 16 persons (27.6 ± 8.2 years old) completed the research procedure. Of 70 persons with dementia (PDs) residing at the one geriatric health services facilities, only 24 persons met the inclusion criteria, and only nine (N = 9, 83.44 ± 9.45 years old) completed the procedure. Actigraph and ambulatory electrocardiographic instruments measuring autonomic nervous activity were attached to the subjects for 24 hours. Activities and behaviors of PDs and HPs were observed by clinically experienced staff nurses and care workers. High frequency (HF) power indicating parasympathetic activity and LF/HF ratio indicating sympathetic activity were calculated. When awake, PDs’ LF/HF ratio was significantly lower than HP’s (Z = -2.60, p < 0.01), showing significant differences in the LF/HF ratios between waking and sleeping, more than those of the PDs (p < 0.001). Similarly, when awake, significant positive correlations were observed in the LF/HF ratio and actigraph activity count (AC) in 11 HPs and 3 PDs (range r = 0.17 to 0.49, p < 0.05);however, significant negative correlation was found in HF and AC of 12 HPs and 3 PDs (range r = -0.55 to -0.18, p < 0.05). While sleeping, significant positive correlations were observed in LF/HF and AC of 3 HPs and 1 PD (range r = 0.35 to 0.42, p < 0.05) and significant negative correlation was found in the HF and AC of 1 HP (r= -0.32, p < 0.001) and 1 PD (r = -0.32, p < 0.05). The mean value of LF/HF in a wakeful state was significantly lower for PDs than HPs. Combined results of behavioral observation, actigrapy and heart rate variability (HRV) analyses suggested that PDs showed positive correlations between LF/HF and AC in a wakeful state. Compared to those who showed no positive correlation, they did not require much nursing care.

Effects of Yoga Exercises on Heart Rate Variability Parameters and Perceived Stress in Adolescent Students with High Score in Perceived Stress

Introduction: Hatha Yoga is a widely used form of holistic mind-body therapy for promoting health, and disease prevention like cardiovascular risks and part of treatment for neurological disorders. Objective: The aim of this study was to evaluate the effect of Hatha yoga on the autonomic nervous system by tracking acute changes in the time-domain and frequency-domain metrics of heart rate variability (HRV) in healthy International Baccalaureate students arranged in 3 different groups. Methods: The prospective interventional study was conducted among adolescent students in China. Thirty-six adolescent students were divided in three groups: 12 Hatha yoga experimental group participants;a control group of 12 students without participation in any activity and a recreational sport group of 12 other students. Outcomes measured were HRV parameters such as SDNN, RMSSD LF, HF, and LF/HF. Also, a Competitive State Anxiety Inventory-2 was used to measure stress and anxiety score in terms of Cognitive stress, Somatic Stress and Self Confidence. Results: Compared to baseline values, the Hatha yoga experiment group demonstrated a significant increase in HRV indices: SDNN 87.62 ± 13.89 (>0.0001) and RMSDD 86.61 ± 7.78 (>0.0001) respectively. In contrast it was documented after the 3 weeks of exposure to yoga training a statistically significant decrease in the frequency domain of LF 1911.53 ± 882.15 (0.0464) compared to baseline values. After completion of intervention the yoga experiment group HF (ms2) values were increased 3430.40 ± 858.38 (>0.0001). Decrease and increase in the HF (ms2) in the control and Hatha yoga group were statistically significant after following Hatha yoga. Cognitive anxiety 18.08 ± 6.30 (>0.0001) and Somatic anxiety 17.50 ± 6.33 (>0.0001) decreased after intervention with yoga and self-confidence increased significantly 32.50 ± 1.17 (>0.0001). Conclusions: The investigation showed a significant increase of HRV parameters and cardiac autonomic function as a result of exposure to Yoga practice. Also, there was significant evidence of decrease in cognitive stress and somatic stress;increased values of self-confidence at the end of three weeks yoga exposure in comparison to the baseline values.