scholarly journals Combined moderate and high intensity exercise with dietary restriction improves cardiac autonomic function associated with a reduction in central and systemic arterial stiffness in obese adults: a clinical trial

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3900 ◽  
Author(s):  
Min Hu ◽  
Shen Wang ◽  
Dan Wang ◽  
Qinhao Lai ◽  
Xiaoying Chen ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Stiffness ◽  
Low Frequency ◽  
Obese Adults ◽  
Diet And Exercise ◽  
Low Frequency Power ◽  
Normalized Units ◽  
Frequency Power ◽  
Cardiac Autonomic Activity

Objective The present study aimed to assess the effects of exercise with dietary restriction on cardiac autonomic activity, arterial stiffness, and cardiovascular biomarkers in obese individuals. Methods Seventeen obese adults completed an 8-week exercise and dietary program. Anthropometry, body composition, and multiple biochemical markers were measured. We used carotid-femoral pulse wave velocity (cfPWV), brachial-ankle pulse wave velocity (baPWV), central blood pressure, and augmentation index (AIx) to assess arterial stiffness. To determine cardiac autonomic activity, heart rate variability (HRV) was analyzed by standard deviation of normal-to-normal intervals (SDNN), square root of the mean squared differences of successive normal-to-normal intervals (RMSSD), total power (TF), low-frequency power in normalized units (LFnu), high-frequency power in normalized units (HFnu), and low-frequency power/high-frequency power (LF/HF). Results Following the exercise and diet intervention, obese subjects had significant reductions in body weight, body mass index, body fat percentage, brachial systolic blood pressure, and resting heart rate, and they had shown improvements in blood chemistry markers such as lipid profiles, insulin, and high-sensitivity C-reactive protein. There was a significant reduction in both cfPWV and baPWV following the intervention when compared to baseline levels. Moreover, the AIx and aortic systolic blood pressure were significantly reduced after the intervention. The diet and exercise intervention significantly increased cardiac autonomic modulation (determined by improved SDNN, RMSSD, TP LF, HF, and LF/HF), which was partly due to changes in heart rate, insulin resistance, and the inflammatory pattern. Furthermore, we observed a correlation between enhanced cardiac autonomic modulation (LF/HF) and decreased arterial stiffness, as measured by central cfPWV and systemic baPWV. Discussion An 8-week combined intervention of diet and exercise is effective in improving cardiac autonomic function in obese adults, with an associated decrease in central and systemic arterial stiffness.

Preeclamptic pregnancy is associated with increased sympathetic and decreased parasympathetic control of HR

2000 ◽  
Vol 278 (4) ◽  
pp. H1269-H1273 ◽  
Author(s):  
Cheryl C. H. Yang ◽  
Te-Chang Chao ◽  
Terry B. J. Kuo ◽  
Chang-Sheng Yin ◽  
Hsing I. Chen
Keyword(s):  
Heart Rate ◽  
Low Frequency ◽  
Normal Pregnancy ◽  
Frequency Domain Analysis ◽  
Natural Logarithm ◽  
Sympathetic Regulation ◽  
History Of ◽  
Low Frequency Power ◽  
Normalized Units ◽  
Frequency Power

Previous work from our laboratory using heart rate variability (HRV) has demonstrated that women before menopause have a more dominant parasympathetic and less effective sympathetic regulations of heart rate compared with men. Because it is still not clear whether normal or preeclamptic pregnancy coincides with alternations in the autonomic functions, we evaluated the changes of HRV in 17 nonpregnant, 17 normotensive pregnant, and 11 preeclamptic women who were clinically diagnosed without history of diabetic neuropathy, cardiac arrhythmia, and other cardiovascular diseases. Frequency-domain analysis of short-term, stationary R-R intervals was performed to evaluate the total variance, low-frequency power (LF; 0.04–0.15 Hz), high-frequency power (HF; 0.15–0.40 Hz), ratio of LF to HF (LF/HF), and LF in normalized units (LF%). Natural logarithm transformation was applied to variance, LF, HF, and LF/HF for the adjustment of the skewness of distribution. We found that the normal pregnant group had a lower R-R value and HF but had a higher LF/HF and LF% compared with the nonpregnant group. The preeclamptic group had lower HF but higher LF/HF compared with either the normal pregnant or nonpregnant group. Our results suggest that normal pregnancy is associated with a facilitation of sympathetic regulation and an attenuation of parasympathetic influence of heart rate, and such alterations are enhanced in preeclamptic pregnancy.

Cardiovascular variability after arousal from sleep: time-varying spectral analysis

2003 ◽  
Vol 95 (4) ◽  
pp. 1394-1404 ◽  
Author(s):  
Anna Blasi ◽  
Javier Jo ◽  
Edwin Valladares ◽  
Barbara J. Morgan ◽  
James B. Skatrud ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
High Frequency ◽  
Low Frequency ◽  
Sleep Time ◽  
Respiratory Pattern ◽  
Time Varying ◽  
High Frequency Power ◽  
Low Frequency Power ◽  
Frequency Power

We performed time-varying spectral analyses of heart rate variability (HRV) and blood pressure variability (BPV) recorded from 16 normal humans during acoustically induced arousals from sleep. Time-varying autoregressive modeling was employed to estimate the time courses of high-frequency HRV power, low-frequency HRV power, the ratio between low-frequency and high-frequency HRV power, and low-frequency power of systolic BPV. To delineate the influence of respiration on HRV, we also computed respiratory airflow high-frequency power, the modified ratio of low-frequency to high-frequency HRV power, and the average transfer gain between respiration and heart rate. During cortical arousal, muscle sympathetic nerve activity and heart rate increased and returned rapidly to baseline, but systolic blood pressure, the ratio between low-frequency and high-frequency HRV power, low-frequency HRV power, the modified ratio of low-frequency to high-frequency HRV power, and low-frequency power of systolic BPV displayed increases that remained above baseline up to 40 s after arousal. High-frequency HRV power and airflow high-frequency power showed concommitant decreases to levels below baseline, whereas the average transfer gain between respiration and heart rate remained unchanged. These findings suggest that 1) arousal-induced changes in parasympathetic activity are strongly coupled to respiratory pattern and 2) the sympathoexcitatory cardiovascular effects of arousal are relatively long lasting and may accumulate if repetitive arousals occur in close succession.

Heart rate response and parasympathetic modulation during recovery from exercise in boys and men

2014 ◽  
Vol 39 (8) ◽  
pp. 969-975 ◽  
Author(s):  
Justin P. Guilkey ◽  
Matthew Overstreet ◽  
Bo Fernhall ◽  
Anthony D. Mahon
Keyword(s):  
Heart Rate ◽  
Maximal Exercise ◽  
Ventilatory Threshold ◽  
Heart Rate Recovery ◽  
Low Frequency ◽  
Cycle Ergometer ◽  
Submaximal Exercise ◽  
Frequency Domains ◽  
Low Frequency Power ◽  
Frequency Power

The purpose of this study was to examine the influence of postexercise parasympathetic modulation, measured by heart rate variability (HRV), on heart rate recovery (HRR) in boys (n = 13, 10.1 ± 0.8 years) and men (n = 13, 23.9 ± 1.5 years) following maximal and submaximal exercise. Subjects completed 10 min of supine rest, followed by graded exercise on a cycle ergometer to maximal effort. On a separate day, subjects exercised at an intensity equivalent to ventilatory threshold. Immediately following both exercise bouts, 1-min HRR was assessed in the supine position. HRV was analyzed under controlled breathing during the final 5 min of rest and recovery in the time and frequency domains and transformed to natural log (ln) values. Boys had a greater 1-min HRR than men following maximal (58 ± 8 vs. 47 ± 11 beats·min−1) and submaximal (59 ± 8 vs. 47 ± 15 beats·min−1) exercise (p < 0.05). Following maximal exercise, boys had greater ln root mean square successive differences in R-R intervals (2.52 ± 0.95 ms), ln standard deviation of NN intervals (3.34 ± 0.57 ms), ln high-frequency power (4.32 ± 2.00 ms2), and ln low-frequency power (4.98 ± 1.17 ms2) than men (1.33 ± 0.37 ms, 2.52 ± 0.24 ms, 1.32 ± 1.06 ms2 and 2.80 ± 0.74 ms2, respectively) (p < 0.05). There were no differences in any HRV variables between groups following submaximal exercise (p > 0.05). In conclusion, it appears that greater parasympathetic modulation accounts for greater HRR following maximal exercise in boys versus men. Although submaximal HRR was greater in boys, parasympathetic responses were similar between groups.

scholarly journals Heart Rate Variability-Derived Features Based on Deep Neural Network for Distinguishing Different Anaesthesia States

2020 ◽  
Author(s):  
Jian Zhan ◽  
Zuo-xi Wu ◽  
Zhen-xin Duan ◽  
Gui-ying Yang ◽  
Zhi-yong Du ◽  
...  
Keyword(s):  
Neural Network ◽  
Heart Rate ◽  
Support Vector Machine ◽  
Logistic Regression ◽  
Decision Tree ◽  
Deep Neural Network ◽  
Low Frequency ◽  
Support Vector ◽  
Low Frequency Power ◽  
Frequency Power

Abstract Background: Estimating the depth of anaesthesia (DoA) is critical in modern anaesthetic practice. Multiple DoA monitors based on electroencephalograms (EEGs) have been widely used for DoA monitoring; however, these monitors may be inaccurate under certain conditions. In this work, the hypothesis that heart rate variability (HRV)-derived features based on a deep neural network can distinguish different anaesthesia states was investigated.Methods: A novel method of distinguishing different anaesthesia states was developed based on four HRV-derived time and frequency domain features combined with a deep neural network. Four features were extracted from an electrocardiogram, including the HRV high-frequency power, low-frequency power, high-to-low-frequency power ratio, and sample entropy. Next, these features were used as inputs for the deep neural network, which used the expert assessment of consciousness level as the reference output. Finally, the deep neural network was compared with the logistic regression, support vector machine, and decision tree models. The datasets of 23 anaesthesia patients were used to assess the proposed method.Results: The accuracies of the four models, in distinguishing the anaesthesia states, were 86.2% (logistic regression), 87.5% (support vector machine), 87.2% (decision tree), and 90.1% (deep neural network). The accuracy of deep neural network was higher than those of the logistic regression (p < 0.05), support vector machine (p < 0.05), and decision tree (p < 0.05) approaches. Our method outperformed the logistic regression, support vector machine, and decision tree methods.Conclusions: The incorporation of four HRV-derived time and frequency domain features and a deep neural network could accurately distinguish between different anaesthesia states; however, this study is a pilot of a feasibility study, providing a method to supplement DoA monitoring based on EEG features to improve the accuracy of DoA estimation.

Normalized Low Frequency Power of Heart Rate Variability Correlates Negatively With the SOFA Score in Severe Sepsis and Septic Shock

CHEST Journal ◽  
2011 ◽  
Vol 140 (4) ◽  
pp. 427A
Author(s):  
Subhasis Behera ◽  
Samuel Brown ◽  
Jason Jones ◽  
Michael Lanspa ◽  
Kathryn Kuttler ◽  
...  
Keyword(s):  
Heart Rate ◽  
Septic Shock ◽  
Heart Rate Variability ◽  
Severe Sepsis ◽  
Sofa Score ◽  
Low Frequency ◽  
Low Frequency Power ◽  
Sepsis And Septic Shock ◽  
Frequency Power

scholarly journals 0461 Blunted Baroreflex Sensitivity and Reduced Morning Parasympathetic Activity in Sleep-Onset Insomnia

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A177-A177
Author(s):  
H Tsai ◽  
T Kuo ◽  
C Yang
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Cardiovascular Events ◽  
Blood Pressure Variability ◽  
Baroreflex Sensitivity ◽  
Sleep Onset ◽  
Low Frequency ◽  
Sleep Structure ◽  
Frequency Power

Abstract Introduction Insomnia is a risk factor for hypertension and cardiovascular events, and this association is strongest for sleep-onset insomnia. However, little is known about insomnia on cardiovascular modulation, especially soon after morning awakening, the peak period of time for cardiovascular incidents. This study explored morning cardiovascular function in individuals with sleep-onset insomnia by analysing heart rate variability, blood pressure variability, and baroreflex sensitivity. Methods Sleep structure of the participants (15 good sleepers and 13 individuals with sleep-onset insomnia) was measured by laboratory polysomnography, followed by continuous recordings of the participant’s blood pressure and heart rate for 10 min in the morning. Results When compared to the good sleepers, the insomnia group showed significant reductions in total sleep time, a longer sleep-onset latency, and reduced sleep efficiency. The sleep structure, including durations of sleep stages, numbers of awakenings and arousal index did not differ between the groups. After morning awakening (averaged time: 12.33 ± 10.48 min), the shorter R-R intervals, lower total power, and lower high-frequency power of heart rate variability were observed among individuals with sleep-onset insomnia, compared with good sleepers. Elevated slopes of systolic and diastolic blood pressure, as well as lower baroreflex sensitivity, were also shown in the insomnia group. Indices of sympathetic activity, including low-frequency percentage of heart rate variability or low-frequency power of blood pressure variability, did not differ between the groups. Conclusion Weak vagal activity and blunted baroreflex sensitivity were evident among sleep-onset insomnia. These findings indicate difficulty in initiating sleep, without significant sleep fragmentation, can independently affect morning cardiovascular function. This study provides a possible link between sleep-onset insomnia and risk of cardiovascular events. Support N/A

Supine low-frequency power of heart rate variability reflects baroreflex function, not cardiac sympathetic innervation

2009 ◽  
Vol 76 (4 suppl 2) ◽  
pp. S51-S59 ◽  
Author(s):  
Jeffrey P. Moak ◽  
David S. Goldstein ◽  
Basil A. Eldadah ◽  
Ahmed Saleem ◽  
Courtney Holmes ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Sympathetic Innervation ◽  
Low Frequency ◽  
Cardiac Sympathetic Innervation ◽  
Baroreflex Function ◽  
Low Frequency Power ◽  
Frequency Power

Reproducibility of Heart Rate Variability Measures in Patients with Chronic Heart Failure

1996 ◽  
Vol 91 (4) ◽  
pp. 391-398 ◽  
Author(s):  
Piotr Ponikowski ◽  
Massimo Piepoli ◽  
Aham A. Amadi ◽  
Tuan Peng Chua ◽  
Derek Harrington ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Chronic Heart Failure ◽  
Time Domain ◽  
Low Frequency ◽  
Variation Coefficient ◽  
Very Low Frequency ◽  
Low Frequency Power ◽  
Frequency Power

1. In patients with chronic heart failure, heart rate variability is reduced with relative preservation of very-low-frequency power (< 0.04 Hz). Heart rate variability has been measured without acceptable information on its stability and the optimal recording periods for enhancing this reproducibility. 2. To this aim and to establish the optimal length of recording for the evaluation of the very-low-frequency power, we analysed 40, 20, 10 and 5 min ECG recordings obtained on two separate occasions in 16 patients with chronic heart failure. The repeatability coefficient and the variation coefficient were calculated for the heart rate variability parameters, in the time-domain (mean RR, SDRR and pNN50), and in the frequency-domain: very low frequency (< 0.04 Hz), low frequency (0.04–0.15 Hz), high frequency (0.15–0.40 Hz), total power (0–0.5 Hz). 3. Mean RR remained virtually identical over time (variation coefficient 8%). The reproducibility of time-domain (variation coefficient 25–139%) and of spectral measures (variation coefficient 45–111%) was very low. The stability of the heart rate variability parameters was only apparently improved after square root and after log transformation. 4. Very-low-frequency values derived from 5 and 10 min intervals were significantly lower than those calculated from 40 and 20 min intervals (P < 0.005). Discrete very-low-frequency peaks were detected in 11 out of 16 patients on the first 40, 20 and 10 min recording, but only in seven out of 16 when 5 min segments were analysed. 5. The reproducibility of both time or frequency-domain measures of heart rate variability in patients with chronic heart failure may vary significantly. Square root or log-transformed parameters may be considered rather than absolute units in studies assessing the influence of management on heart rate variability profile. Recordings of at least 20 min in stable, controlled conditions are to be recommended to optimize signal acquisition in patients with chronic heart failure, if very-low-frequency power in particular is to be studied.

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