Rhythm Of Heart Rate Variability Research Articles

Effects of long-term transcutaneous auricular vagus nerve stimulation on circadian vagal activity in people with Prader-Willi Syndrome: A case-series

BackgroundPrader-Willi Syndrome (PWS) is a genetic neurodevelopmental disorder marked by disruptions in circadian rhythms and autonomic nervous system (ANS) activity, hyperphagia, and episodes of emotional outbursts. Previous trials suggest that both invasive and non-invasive vagus nerve stimulation (VNS) can reduce emotional outbursts in PWS, potentially through its effects on vagal activity. AimThis case series investigated the effects of transcutaneous auricular VNS (taVNS) on cardiac markers of circadian vagal activity, specifically heart rate variability (HRV) and heart rate (HR), and their potential links to improvements in emotional outbursts. MethodsFive individuals with PWS (mean age: 26.9 years; 3 males, 2 females) received four hours of daily taVNS for 12 months, followed by one month of two-hour daily sessions. Outcome measures included daily recording of emotional outbursts and every three months 24-h HRV and HR recordings. Mixed cosinor models were applied to analyze changes in circadian rhythms of HRV and HR. A linear mixed model was used to assess the predictive value of cardiac vagal activity on emotional outbursts. ResultsCircadian amplitudes of HRV and HR were significantly higher at the end of the treatment compared to baseline (all p’s < .01). There was a significant increase in the rhythm-adjusted mean of HRV (p < .01), while the rhythm-adjusted HR mean significantly decreased, both indicating increased cardiac vagal activity. Higher rhythm-adjusted mean HRV predicted a lower number of emotional outbursts. ConclusionThe results suggest that taVNS may be effective by targeting ANS activity in individuals with PWS, contributing to improvements in behavioral regulation.

Abnormal circadian rhythm of heart rate variability and their association with symptoms in patients with major depressive disorder

BackgroundHeart rate variability (HRV) is often reduced in patients with major depressive disorder (MDD) and is linked to symptoms. However, prior studies have mainly focused on short-term HRV, with limited exploration of the 24-h HRV circadian rhythm, despite its ability to comprehensively capture overall HRV distribution and dynamic fluctuations. In this study, we investigated the circadian rhythms of 24-h HRV indices in patients with MDD and their associations with symptom severity. MethodsWe recorded 24-h electrocardiograms in 73 patients with MDD (53 in major depressive episode and 20 in remission period) and 31 healthy controls. An extended cosine model was used to model the circadian rhythm of six HRV indices by five parameters: the mesor, amplitude, duty cycle, curve smoothness, and acrophase. Symptom severity was evaluated using the Hamilton Depression Scale and Hamilton Anxiety Scale. ResultsCompared with the control group, patients with MDD had a significantly smaller SampEn mesor, higher HF duty cycle, and lower heart rate (HR) duty cycle. They also had a significantly higher curve smoothness for HR, RMSSD, and HF. The mesor for SampEn, along with the curve smoothness for HR and ln RMSSD, were associated with certain symptoms in patients with MDD.Limitations.The cross-sectional design and psychiatric treatment of most patients with MDD limited our findings. ConclusionPatients with MDD exhibit abnormal HRV circadian rhythms that are associated with symptoms. Moreover, 24-h ECG monitoring may potentially serve as an adjunct value to objectively evaluate clinical symptoms in these patients.

Effects of chronotype on sleep, mood and cardiovascular circadian rhythms in rotating night shift medical workers.

Whether chronotype affects the health outcomes of night shift work populations is unknown. This study aimed to assess the influence of different chronotypes in the rotating night shift population on sleep status, mood, blood pressure (BP), and heart rate variability (HRV), as well as the circadian rhythm of BP and HRV. A total of 208 rotating night shift workers were included. All participants completed structured questionnaires to assess chronotype, mood and sleep status. During their daily lives outside of the night shift, they underwent 24-hour Holter electrocardiogram monitoring and 24-hour ambulatory blood pressure monitoring. Day-time and night-time BP and BP dipping were obtained. Day-time and night-time HRV values (SDNN, RMSSD, LF, HF, LF nu, SD1, SD2 and SD2/SD1) were calculated and fitted to the cosine period curve. Three circandian parameters (mesor, amplitude and acrophase) were extracted to quantify the circadian rhythm of the HRV indices. Among all three groups, E-type showed more fatigue and sleepiness. In addition, E-type showed blunted diastolic BP dipping. Notably, E-type showed association with higher RMSSD, LF, HF and SD1 in the night time, and higher mesors of RMSSD and LF and amplitude of SD2/SD1 in circadian analysis. Chronotype is a factor affecting fatigue, sleepiness and cardiovascular circadian rhythms of rotating night shift workers. Chronotype should be taken into consideration for managing night-shift rotation to promote occupational health.

The value of circadian heart rate variability for the estimation of obstructive sleep apnea severity in adult males.

Heart rate variability (HRV) is becoming more prevalent as a measurable parameter in wearable sleep-monitoring devices, which are simple and effective instruments for illness evaluation. Currently, most studies on investigating OSA severity and HRV have measured heart rates during wakefulness or sleep. Therefore, the objective of this study was to investigate the circadian rhythm of HRV in male patients with OSA and its value for the estimation of OSA severity using group-based trajectory modeling. Patients with complaints of snoring were enrolled from the Sleep Center of Shandong Qianfoshan Hospital. Patients were divided into 3 groups according to apnea hypopnea index (AHI inevents/h), as follows: (<15, 15≤AHI<30, and ≥30). HRV parameters were calculated using 24 h Holter monitoring, which included time-domain and frequency-domain indices. Circadian differences in the standard deviation of normal to normal (SDNN) were evaluated for OSA severity using analysis of variance, trajectory analysis, and multinomial logistic regression. A total of 228 patients were enrolled, 47 with mild OSA, 48 moderate, and 133 severe.Patients with severe OSA exhibited reduced triangular index and higher very low frequency than those in the other groups. Circadian HRV showed that nocturnal SDNN was considerably higher than daytime SDNN in patients with severe OSA. The difference among the OSA groups was significant at 23, 24, 2, and 3 o'clock sharp between the severe and moderate OSA groups (all P<0.05). The heterogeneity of circadian HRV trajectories in OSA was strongly associated with OSA severity, including sleep structure and hypoxia-related parameters. Among the low-to-low, low-to-high, high-to-low, and high-to-high groups, OSA severity in the low-to-high group was the most severe, especially compared with the low-to-low and high-to-low SDNN groups, respectively. Circadian HRV in patients with OSA emerged as low daytime and high nocturnal in SDNN, particularly in men with severe OSA. The heterogeneity of circadian HRV revealed that trajectories with low daytime and significantly high nighttime were more strongly associated with severe OSA. Thus, circadian HRV trajectories may be useful to identify the severity of OSA.

Correlation of Circadian Rhythms of Heart Rate Variability Indices with Stress, Mood, and Sleep Status in Female Medical Workers with Night Shifts.

PurposeHeart rate variability (HRV) indices have been used as stress indicators. Rare studies investigated the associations of circadian rhythms of the HRV indices with the stress, mood, and sleep conditions in populations under stress.MethodsIn total 257 female participants (203 shift workers and 54 non-shift workers) were included. All the participants completed a structured questionnaire to assess the stress, mood, and sleep conditions and performed 24-hour Holter electrocardiogram monitoring on the day away from shifts. Using epochs of 1-min or 5-min beat-to-beat intervals, the HRV indices (SDNN, RMSSD, LF, HF, LF/HF, and LFnu, SD1, SD2, SD1/SD2) were plotted as a function of time and fitted into cosine periodic curves, respectively. Three mathematical parameters based on the cosine periodic curves were extracted, MESOR (M, overall averages of the cosine curve), amplitude (A, amplitude of the peak of the cosine curve), and acrophase (θ, latency to the peak) to quantify the circadian rhythms of the HRV indices. Multivariable linear regression models were used to reveal the associations of these parameters with the clinical assessments of stress, mood, or sleep conditions, as well as with the 24-h averages of the HRV indices.ResultsThe parameters M and A of SDNN, RMSSD, LF, and HF, and θ of LF/HF and LFnu significantly differ between shift and non-shift workers. The parameter θ of LF/HF positively correlates with the severity of stress and anxiety. The parameter A of LF/HF and LFnu also positively correlates with daytime sleepiness and sleep fragmentation. In addition, the parameters M and A instead of θ of SDNN, RMSSD, LF, LF/HF, and LFnu significantly correlate with the 24-h averages of HRV indices.ConclusionThe circadian rhythms of the HRV indices over 24 hours can, to some extent, predict the severity of stress, emotion and sleep conditions in female populations under stress.

Heart Rate Variability as an Indicator of Autonomic Nervous System Disturbance in Behcet's Disease.

BackgroundBehçet’s disease (BD) is a multisystemic vasculiti where cardiac involvement is not common. Previous studies have shown that the incidence of ventricular arrhythmia and sudden cardiac death (SCD) is higher in patients with BD than in the healthy population. Among various possible explanations, autonomic nervous system (ANS) dysfunction has been suggested. Few studies have evaluated ANS function in patients with BD, and the results obtained are controversial.ObjectiveWe aimed to assess cardiac autonomic function by heart rate variability (HRV) in patients with BD; to evaluate circadian changes in HRV; and to study the relationship between HRV parameters and disease parameters.MethodsThirty-six patients with Behçet’s disease (median age 42 years, 28 men) and 36 age- and sex-matched healthy volunteers were included. HRV analyses were performed in the time and frequency domains for the entire 24-hour period and for the daytime and nighttime periods. BD activity was studied with Behcet’s disease current activity form (BDCAF).ResultsPatients with BD had significantly lower values of SDNN compared to controls. PNN50, RMSSD, and HF components mean values were significantly reduced in patients than in controls implying parasympathetic impairment. LF was comparable between the two groups, whereas LF/HF ratio was significantly higher in BD group. The circadian rhythm of HRV was preserved in patient group. There was no significant correlation of CRP or disease duration with HRV indices in Behçet’s subjects. BDCAF score was found to be negatively correlated with LF/HF.ConclusionPatients with BD, despite no cardiovascular involvement, have reduced parasympathetic activity compared with controls. However, circadian rhythms of autonomic function were preserved. As known, there is strong evidence for the role of the ANS in the pathogenesis of ventricular arrhythmias. Thus, being a practical tool, HRV can be an interesting approach for the rhythmic follow-up of BD patients.

Effect of short-term exposure to particulate air pollution on heart rate variability in normal-weight and obese adults

BackgroundThe adverse effects of particulate air pollution on heart rate variability (HRV) have been reported. However, it remains unclear whether they differ by the weight status as well as between wake and sleep.MethodsA repeated-measure study was conducted in 97 young adults in Beijing, China, and they were classified by body mass index (BMI) as normal-weight (BMI, 18.5–24.0 kg/m2) and obese (BMI ≥ 28.0 kg/m2) groups. Personal exposures to fine particulate matter (PM2.5) and black carbon (BC) were measured with portable exposure monitors, and the ambient PM2.5/BC concentrations were obtained from the fixed monitoring sites near the subjects’ residences. HRV and heart rate (HR) were monitored by 24-h Holter electrocardiography. The study period was divided into waking and sleeping hours according to time-activity diaries. Linear mixed-effects models were used to investigate the effects of PM2.5/BC on HRV and HR in both groups during wake and sleep.ResultsThe effects of short-term exposure to PM2.5/BC on HRV were more pronounced among obese participants. In the normal-weight group, the positive association between personal PM2.5/BC exposure and high-frequency power (HF) as well as the ratio of low-frequency power to high-frequency power (LF/HF) was observed during wakefulness. In the obese group, personal PM2.5/BC exposure was negatively associated with HF but positively associated with LF/HF during wakefulness, whereas it was negatively correlated to total power and standard deviation of all NN intervals (SDNN) during sleep. An interquartile range (IQR) increase in BC at 2-h moving average was associated with 37.64% (95% confidence interval [CI]: 25.03, 51.51%) increases in LF/HF during wakefulness and associated with 6.28% (95% CI: − 17.26, 6.15%) decreases in SDNN during sleep in obese individuals, and the interaction terms between BC and obesity in LF/HF and SDNN were both statistically significant (p < 0.05). The results also suggested that the effects of PM2.5/BC exposure on several HRV indices and HR differed in magnitude or direction between wake and sleep.ConclusionsShort-term exposure to PM2.5/BC is associated with HRV and HR, especially in obese individuals. The circadian rhythm of HRV should be considered in future studies when HRV is applied.Graphical abstract

Ultradian rhythms in heart rate variability and distal body temperature anticipate onset of\xa0the luteinizing hormone surge

The menstrual cycle is characterized by predictable patterns of physiological change across timescales. Although patterns of reproductive hormones across the menstrual cycle, particularly ultradian rhythms, are well described, monitoring these measures repeatedly to predict the preovulatory luteinizing hormone (LH) surge is not practical. In the present study, we explored whether non-invasive measures coupled to the reproductive system: high frequency distal body temperature (DBT), sleeping heart rate (HR), sleeping heart rate variability (HRV), and sleep timing, could be used to anticipate the preovulatory LH surge in women. To test this possibility, we used signal processing to examine these measures in 45 premenopausal and 10 perimenopausal cycles alongside dates of supra-surge threshold LH and menstruation. Additionally, urinary estradiol and progesterone metabolites were measured daily surrounding the LH surge in 20 cycles. Wavelet analysis revealed a consistent pattern of DBT and HRV ultradian rhythm (2–5 h) power that uniquely enabled anticipation of the LH surge at least 2 days prior to its onset in 100% of individuals. Together, the present findings reveal fluctuations in distal body temperature and heart rate variability that consistently anticipate the LH surge, suggesting that automated ultradian rhythm monitoring may provide a novel and convenient method for non-invasive fertility assessment.

Influence of ageing on circadian rhythm of heart rate variability in healthy subjects

The analysis of the circadian rhythm of heart rate variability (HRV) represents a relevant physiological tool to assess the vagal system. However, the influence of age (mostly >75 years) on HRV is not widely known. The aim of this study was to evaluate the influence of age on HRV, particularly in the elderly and to identify a model of this relationship. The study was carried out by examining linear and nonlinear parameters extracted from HRV, including individuals over 75 years for which there is no research available. Data from 140 healthy subjects were sex matched and divided into young (young group: 15-39 years old), adult (adult group: 40-64 years old) and senior (senior group: 65-90 years old) groups. 24-h Holter monitoring was used and several HRV parameters were extracted from time, and spectral and nonlinear analyses were examined. Time-domain parameters, mainly standard deviation of the NN interval (SDNN) and number of successive differences of intervals which differ by more than 50 ms, presented significant differences between the young group and the other two groups during the 24-h period, while normalized spectral parameters (LFn, HFn and low frequency/high frequency), as well as nonlinear parameters, mainly β exponent and fractal dimension, showed significant difference between the senior group and the other two groups. All these parameters showed a similar circadian rhythm with significant differences between the mean day and night values, especially in young and adult group cohorts. Moreover, a parabolic relationship between these parameters and age was highlighted with an opposite trend over about 60 years compared with younger people. A progressive physiological autonomic imbalance is present in ageing. The inverse trend in the relation between HRV parameters and age found in the senior group could be mainly due to a faster fluctuation of RR. This should be considered when studying changes in the cardiac autonomic nervous control.

AGE AND GENDER PECULIARITIES OF HEART RATE VARIABILITY IN HEALTHY ADOLESCENTS

Introduction. The aim of the study was to find out gender and age peculiarities of the circadian rhythm of heart rate variability in healthy adolescents. Materials and methods: holter-ECG (spectral and temporal parameters of heart rate variability). 354 healthy adolescents were recruited to participate in this study. Results: adolescent girls have higher impact of parasympathetic nervous system to the heart rate modulation in comparison with boys. Relative power of the high-frequency band increased at night in girls and didn't significantly change in boys. Relative power of the low-frequency band decreased at night both in girls and in boys. Conclusion. The activity of divisions of autonomic nervous system in adolescents has circadian profile and differ in children of different sex and age.

The analysis of circadian rhythm of heart rate variability in patients with drug-resistant epilepsy

ObjectiveThe aim of this study was to investigate the variations and the circadian rhythm of multi-domain parameters of heart rate variability (HRV) in patients with drug-resistant epilepsy. MethodsTime domain HRV parameters of 24-hour data, frequency and non-linear domain HRV parameters were calculated using a 24-hour ambulatory electrocardiogram (ECG) from subjects in a resting and awake state (5-min data from 9:00-10:00 a.m.). Circadian fluctuation (24 one-hour segments) and the night (00:00 - 05:00)/ day (07:30 - 09:30) ratio of each HRV parameter were measured in (i) refractory epilepsy (n = 51) and (ii) healthy, age and sex matched controls (n = 50). Cosinor fit method was used to quantify the pattern of the circadian rhythm of HRV. ResultsCompared to healthy controls, patients with drug-resistant epilepsy had significantly decreased time domain (mean_RR, STDRR, RMSSD, pNN50, HRV_triangular_index), frequency domain (VLF_power, LF_power, HF_power, Total_power) and non-linear domain (Poincaré SD1, SD2, D2) HRV measurements. There were also overall reductions in amplitude and the baseline of circadian curves of HRV parameter in the patients group, especially nocturnal inhibition of cardiac autonomic modulations was stronger than that in daytime. The majority of differences in HRV values between the two groups reached a maximum in early morning (usually 5:00 or 6:00 a.m.). No significant differences were found in the night/day ratios of multi-domain HRV measurements between patients and healthy controls (p = 0.862). ConclusionsThe significant suppression of HRV parameters in patients with refractory epilepsy may reflect the inhibitions of both sympathetic and parasympathetic activities. This is notably the first time that marked circadian diversity of HRV measurments between the patient and control groups were found and quantified by cosinor fit method. The difference in amplitude increased during night with peak occurrence between 5:00 or 6:00 a.m. These findings may be linked to cardiac autonomic dysfunction and subsequent sudden unexpected death in epilepsy (SUDEP), which is reported to often occur during night or early morning. Taken together, HRV parameters may be potential bio-markers for predicting SUDEP.

Identification of a Group's Physiological Synchronization with Earth's Magnetic Field.

A new analysis technique for the evaluation of the degree of synchronization between the physiological state of a group of people and changes in the Earth’s magnetic field based on their cardiac inter-beat intervals was developed and validated. The new analysis method was then used to identify clusters of similar synchronization patterns in a group of 20 individuals over a two-week period. The algorithm for the identification of slow wave dynamics for every person was constructed in order to determine meaningful interrelationships between the participants and the local magnetic field data. The results support the hypothesis that the slow wave rhythms in heart rate variability can synchronize with changes in local magnetic field data, and that the degree of synchronization is affected by the quality of interpersonal relationships.

Synchronization of Human Autonomic Nervous System Rhythms with Geomagnetic Activity in Human Subjects.

A coupling between geomagnetic activity and the human nervous system’s function was identified by virtue of continuous monitoring of heart rate variability (HRV) and the time-varying geomagnetic field over a 31-day period in a group of 10 individuals who went about their normal day-to-day lives. A time series correlation analysis identified a response of the group’s autonomic nervous systems to various dynamic changes in the solar, cosmic ray, and ambient magnetic field. Correlation coefficients and p values were calculated between the HRV variables and environmental measures during three distinct time periods of environmental activity. There were significant correlations between the group’s HRV and solar wind speed, Kp, Ap, solar radio flux, cosmic ray counts, Schumann resonance power, and the total variations in the magnetic field. In addition, the time series data were time synchronized and normalized, after which all circadian rhythms were removed. It was found that the participants’ HRV rhythms synchronized across the 31-day period at a period of approximately 2.5 days, even though all participants were in separate locations. Overall, this suggests that daily autonomic nervous system activity not only responds to changes in solar and geomagnetic activity, but is synchronized with the time-varying magnetic fields associated with geomagnetic field-line resonances and Schumann resonances.

The circadian rhythm of heart rate variability

Purpose: In recent years, the measurement of heart rate variability (HRV) has gained ground even outside research settings in everyday clinical and outpatient practice and in health promotion. Methods: Using the search terms “heart rate variability”, “hrv” and “circadian”, a systematic review was carried out in the PubMed database to find original work that analysed the course of HRV parameters over a 24-h period. Results: A total of 26 original studies were found. Almost all the studies detected a circadian rhythm for the HRV parameters analysed. HRV increased during the night in particular and a nighttime peak during the second half of the night was identified. Conclusions: HRV follows a circadian rhythm. But until today, there isn′t any possibility to make quantitative statements about changes over the course of the day for planning short-term measurements. More qualitative studies must be carried in order to close this knowledge gaps.

Heart Rate Variability: New Perspectives on Physiological Mechanisms, Assessment of Self-regulatory Capacity, and Health risk.

Heart rate variability, the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operates on different time scales to adapt to environmental and psychological challenges. This article briefly reviews neural regulation of the heart and offers some new perspectives on mechanisms underlying the very low frequency rhythm of heart rate variability. Interpretation of heart rate variability rhythms in the context of health risk and physiological and psychological self-regulatory capacity assessment is discussed. The cardiovascular regulatory centers in the spinal cord and medulla integrate inputs from higher brain centers with afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. We also discuss the intrinsic cardiac nervous system and the heart-brain connection pathways, through which afferent information can influence activity in the subcortical, frontocortical, and motor cortex areas. In addition, the use of real-time HRV feedback to increase self-regulatory capacity is reviewed. We conclude that the heart's rhythms are characterized by both complexity and stability over longer time scales that reflect both physiological and psychological functional status of these internal self-regulatory systems.

Circadian variation of heart rate variability during different sleep stages

Introduction Heart rate (HR) and heart rate variability (HRV) have been shown to be influenced by the circadian system during wakefulness and to be affected by sleep. The aim of the present study was to assess the effects of sleep stages on the circadian variation of HRV. Materials and methods Fifteen healthy subjects (12 men, 3 women in follicular phase; mean age ± SD: 24.6 ± 4.5 years) entered the laboratory for an 8-h baseline nocturnal sleep episode during which sleep disorders were ruled out. Upon awakening, they underwent a 72-h ultradian sleep–wake cycle (USW) procedure consisting of 60-min wake episodes in dim light ( 10 lux) alternating with 60-min nap opportunities in darkness. HR was monitored, high and low frequencies (HF, LF), and the LF:HF ratio were calculated as indexes of HRV. Core body temperature (CBT) and polysomnographic sleep recordings were collected throughout the experiment.Circadian phase was determined based on CBT min (0°) and HRV data was analyzed based on circadian phase and its corresponding sleep stage using non-linear mixed models. Results A significant circadian rhythm was observed for HR during each sleep stage (P = 0.002); for HF power during each sleep stage (P = 0.05) except REM sleep; for LF power during each sleep stage (P = 0.02) except slow wave sleep (SWS) and REM sleep; and for the LF:HF ratio only during wake epochs during naps and REM sleep (P = 0.003).During stage 2 sleep and SWS, HR minimum occurred at the beginning of the night, advanced relative to the CBT minimum (P ⩽ 0.03).During REM sleep, HR was maximal around the time of habitual awakening (10:13 ± 0:42).The acrophase of HF and LF power rhythms measured during sleep was aligned with CBT min.There was a trend for the HF power acrophase during SWS to be advanced relative to the CBT min (P = 0.07).The acrophase of the LF:HF ratio during REM sleep occurred in the early morning, significantly advanced compared to that of wake episodes (P 0.001). Conclusion A significant circadian rhythm in parasympathetic cardiac modulation was observed during non-REM sleep with an acrophase around 02:00.Sympathovagal cardiac balance also followed a circadian pattern during REM sleep, with maximal sympathetic cardiac dominance occurring in the early morning.The temporal relationship between sleep stage-specific circadian rhythms in HRV and the diurnal distribution of adverse cardiovascular events lends support to the theory that autonomic balance modulates cardiovascular risks throughout the day. Acknowledgements Research was supported by the Canadian Institutes of Health Research (CIHR). P. Boudreau was supported by Institut de recherche Robert-Sauve en sante et en securite du travail (IRSST).

Circadian Rhythm of Autonomic Cardiovascular Control During Mars500 Simulated Mission to Mars

The Mars500 project was conceived to gather knowledge about the psychological and physiological effects of living in an enclosed environment during 520 d as would be required for a real mission to Mars. Our objective was to investigate the circadian profile of heart rate variability (HRV) in the context of the Mars500 study. Before, during, and after confinement, 24-h EKG records were obtained from the six crewmembers who participated in the mission. Autonomic activity was evaluated through time and frequency domain indexes of HRV analysis. Circadian rhythmicity was assessed both by averaging hourly HRV along wake and sleep scheduled periods and by fitting a 24-h harmonic to the hourly means. During confinement, wake HRV showed (mean +/- SE) a progressive increase in mean RR interval (from 778 +/- 24 ms to 916 +/- 42 ms), and in the amplitude (values are wavelet power coefficients) of very low (from 13.3 +/- 0.3 to 14.1 +/- 0.2) and high (from 7.8 +/- 0.4 to 8.3 +/- 0.3) frequency components. During sleep, the relative amplitude of the high frequency component of HRV decreased (from 11.8 +/- 1.6 to 9.4 +/- 1.8 normalized units). Overall, sleep-wake differences of HRV showed a progressive decrease of the relative amplitude of the high frequency component. Also, circadian HRV rhythms were dampened during confinement. Data revealed diminished amplitude of the rest-activity pattern of the autonomic nervous system parasympathetic function. Reduced daylight exposure and mood changes could account for this observation.

Improvement of Circadian Rhythm of Heart Rate Variability by Eurythmy Therapy Training

Background. Impairment of circadian rhythm is associated with various clinical problems. It not only has a negative impact on quality of life but can also be associated with a significantly poorer prognosis. Eurythmy therapy (EYT) is an anthroposophic movement therapy aimed at reducing fatigue symptoms and stress levels. Objective. This analysis of healthy subjects was conducted to examine whether the improvement in fatigue symptoms was accompanied by improvements in the circadian rhythm of heart rate variability (HRV). Design. Twenty-three women performed 10 hours of EYT over six weeks. Electrocardiograms (ECGs) were recorded before and after the EYT trial. HRV was quantified by parameters of the frequency and time domains and the nonlinear parameters of symbolic dynamics. Results. The day-night contrast with predominance of vagal activity at night becomes more pronounced after the EYT training, and with decreased Ultralow and very low frequencies, the HRV shows evidence of calmer sleep. During the night, the complexity of the HRV is significantly increased indicated by nonlinear parameters. Conclusion. The analysis of the circadian patterns of cardiophysiological parameters before and after EYT shows significant improvements in HRV in terms of greater day-night contrast caused by an increase of vagal activity and calmer and more complex HRV patterns during sleep.

Circadian rhythm of heart-rate variability and autonomic cardiovascular regulation in Parkinson's disease

Circadian rhythm of heart-rate variability and autonomic cardiovascular regulation in Parkinson's disease

P5-1 Evaluation of circadian rhythm of heart-rate variability and autonomic cardiovascular function in Parkinson's disease

P5-1 Evaluation of circadian rhythm of heart-rate variability and autonomic cardiovascular function in Parkinson's disease