Frequency-dependent baroreflex modulation of blood pressure and heart rate variability in conscious mice

2005 ◽  
Vol 289 (5) ◽  
pp. H1968-H1975 ◽  
Author(s):  
Rubens Fazan ◽  
Mauro de Oliveira ◽  
Valdo José Dias da Silva ◽  
Luis Fernando Joaquim ◽  
Nicola Montano ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
High Frequency ◽  
Low Frequency ◽  
Systolic Arterial Pressure ◽  
Pulse Interval ◽  
Sham Surgery ◽  
Cardiac Receptors

The goal of this study was to determine the baroreflex influence on systolic arterial pressure (SAP) and pulse interval (PI) variability in conscious mice. SAP and PI were measured in C57Bl/6J mice subjected to sinoaortic deafferentation (SAD, n = 21) or sham surgery ( n = 20). Average SAP and PI did not differ in SAD or control mice. In contrast, SAP variance was enhanced (21 ± 4 vs. 9.5 ± 1 mmHg2) and PI variance reduced (8.8 ± 2 vs. 26 ± 6 ms2) in SAD vs. control mice. High-frequency (HF: 1–5 Hz) SAP variability quantified by spectral analysis was greater in SAD (8.5 ± 2.0 mmHg2) compared with control (2.5 ± 0.2 mmHg2) mice, whereas low-frequency (LF: 0.1–1 Hz) SAP variability did not differ between the groups. Conversely, LF PI variability was markedly reduced in SAD mice (0.5 ± 0.1 vs. 10.8 ± 3.4 ms2). LF oscillations in SAP and PI were coherent in control mice (coherence = 0.68 ± 0.05), with changes in SAP leading changes in PI (phase = −1.41 ± 0.06 radians), but were not coherent in SAD mice (coherence = 0.08 ± 0.03). Blockade of parasympathetic drive with atropine decreased average PI, PI variance, and LF and HF PI variability in control ( n = 10) but had no effect in SAD ( n = 6) mice. In control mice, blockade of sympathetic cardiac receptors with propranolol increased average PI and decreased PI variance and LF PI variability ( n = 6). In SAD mice, propranolol increased average PI ( n = 6). In conclusion, baroreflex modulation of PI contributes to LF, but not HF PI variability, and is mediated by both sympathetic and parasympathetic drives in conscious mice.

scholarly journals Power spectral analysis of heart rate variability in Bangladeshi healthy male and female

2016 ◽  
Vol 43 (3) ◽  
pp. 146-150
Author(s):  
Qazi Farzana Akhter ◽  
Qazi Shamima Akhter ◽  
Farhana Rahman ◽  
Sybilla Ferdousi ◽  
Susmita Sinha
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
High Frequency ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Autonomic Nerve ◽  
Age Group ◽  
Power Spectral

Heart rate variability (HRV) has been considered as an indicator of autonomic nerve function status. We aimed to find out the reference values of heart rate variability by power spectral analysis in our healthy population of both sex. This cross sectional study was conducted in the Department of Physiology, Dhaka Medical College, Dhaka from the period of July 2012 to June 2013. For this, 180 subjects were selected with the age ranging from 15-60 years. All the study subjects were divided into 3 different groups according to age (Group A: 15-30 years; Group B: 31-45 years; Group C: 46-60 years). Each group contained 60 subjects of which 30 were male and 30 were female. Analysis of HRV parameters were done in Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka. Systolic blood pressure, diastolic blood pressure, low frequency normalized unit, low frequency / high frequency ratio were significantly higher in male than female. Again high frequency power, high frequency normalized unit were significantly higher in female than male of same age group. This study concludes that male showed higher cardiac sympathetic activities while female showed higher cardiac parasympathetic activities in different age groups.Bangladesh Med J. 2014 Sep; 43 (3): 146-150

scholarly journals Effect of moderate physical exercises on the relationship of variability of the heart rhythm with the level of blood pressure and hemodynamic functions in women with essential hypertension

2020 ◽  
pp. 64-73
Author(s):  
Б.И. Кузник ◽  
Ю.Н. Смоляков ◽  
Е.С. Гусева ◽  
С.О. Давыдов ◽  
И.В. Файн
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Heart Rate Variability ◽  
Essential Hypertension ◽  
High Frequency ◽  
Low Frequency ◽  
Mean Square ◽  
Positive Correlations ◽  
The Relationship

Цель исследования - выявление взаимосвязи между показателями вариабельности сердечного ритма (ВСР), кровяным давлением и гемодинамическими функциями у женщин, страдающих гипертонической болезнью (ГБ) и находящихся на медикаментозной терапии (ГБ-1), либо в дополнение к этому, проходящих регулярные курсы кинезитерапии (ГБ-2). Методика. Наблюдения проведены на 72 женщинах, страдающих артериальной гипертензией II стадии. В группу ГБ-1 вошли 37 женщин с ГБ, находящихся на медикаментозной терапии, в группу ГБ-2 - 35 женщин с ГБ, которые, помимо медикаментозной терапии, регулярно проходили на протяжении 2-3 лет по 3-4 полуторамесячных курса кинезитерапии (управляемые умеренные физические нагрузки). Для изучения гемодинамики был использован датчик динамического рассеяния света (miniature Dynamic Light Scattering - mDLS) от Elfi-Tech (Rehovot, Israel), измеряющий сигналы, инициированные кожным кровотоком, и использующий методику разложения сигнала на частотные компоненты, связанные с разными гемодинамическими источниками. Из пульсовой компоненты mDLS сигнала извлекалась информация о вариабельности RR-интервалов и рассчитывались индикаторы вариабельности сердечного ритма. Введен показатель «гемодинамический индекс» (Hemodynamic Index - HI). Зависимость HI от скорости сдвига интерпретируется путем сопоставления каждой полосе частот определенной скорости сдвига (HI1 - низкочастотный, HI2 - промежуточный, HI3 - высокочастотный). Использованы следующие относительные (RHI, Relative Hemodynamic Index) и осцилляторные (OHI, Oscillatory Hemodynamic Indexes) гемодинамические индексы: нейрологический (NEUR), Майера (MAYER), дыхательный (RESP) и пульсовой (PULSE). ВСР показатели включали: HR (Heart Rate), PWR (Power) - общую мощность колебаний, LF (Low Frequency), HF (High Frequency), SDNN (Standard Deviation of the Normal-to-Normal), RMSSD (Root Mean Square of the Successive Differences), а также индексы: CVI (Cardiac Vagal Index) и CSI (Cardiac Sympathetic Index). Результаты. У женщин, находящихся исключительно на медикаментозной терапии (ГБ-1), выявляются отрицательные взаимосвязи LF и LF/HF с систолическим, средним и пульсовым давлением. При ГБ-2 проявляются отрицательные связи PWR, LF, HF с пульсовым давлением. При ГБ-1 обнаружены положительные взаимосвязи между HR и гемодинамическими индексами HI1, RHI2 и отрицательная взаимосвязь с RHI3, а также между RMSSD и RHI3 и между HF и HI1/HI3. У пациенток ГБ-2 обнаружена отрицательная корреляция SDNN и RHI1, а также PWR и RHI1; положительные взаимосвязи между PWR и HI2, HI3, RHI2, HF и RHI3 и LF/HF с HI1/HI3; отрицательные связи HF c HI1/HI3 и с RHI1, а также между LF/HF и RHI3, CSI и RHI3. У больных ГБ-1 имеются прямые связи между SDNN, PWR, LF, HF, CVI и NEUR_HI1, что свидетельствует о действии этих факторов на эндотелиальный кровоток (HI1). В группе ГБ-2 установлено наличие лишь положительных связей между LF, HF и NEUR_HI3. У больных ГБ-1 на уровень АД влияют все без исключения осцилляторные ритмы, которые могут оказывать как отрицательное (с MAYER_HI1, PULSE_HI2), так и положительное (MAYER_HI2, RESP_HI3) влияние. У больных ГБ-2 взаимосвязи АД с осцилляторными индексами не обнаружены. Заключение. Уменьшение в группе ГБ-2 по сравнению с больными группы ГБ-1 числа факторов, влияющих на АД и гемодинамику, носит более совершенный и благоприятный характер, что и обеспечивает более быструю и устойчивую нормализацию артериального давления. Aim. To study the relationship between heart rate variability (HRV), blood pressure and hemodynamic functions in women with essential hypertension (EH) receiving a drug therapy alone (EH-1) or in combination with regular courses of kinesitherapy (EH-2). Methods. The study included 72 women with EH. The EH-1 group consisted of 37 women with stage II arterial hypertension. The EH-2 group consisted of 35 women with stage II arterial hypertension who underwent 3-4 1.5-month courses of kinesitherapy (controlled moderate physical activity) on a regular basis for 2-3 years. Hemodynamics was studied with a miniature Dynamic Light Scattering (mDLS) sensor from Elfi-Tech (Rehovot, Israel), which measures signals initiated by the skin blood flow by decomposing the signal into frequency components associated with different hemodynamic sources. Information on the RR interval variability was extracted from the pulse component of mDLS signal, and indicators of heart rate variability were calculated. A Hemodynamic Index (HI) was introduced. The HI dependence on shear rate was interpreted by matching each frequency band with a specific shear rate (HI1, low-frequency; HI2, intermediate; HI3, high-frequency). The following relative (RHI, Relative Hemodynamic Index) and oscillatory (OHI, Oscillatory Hemodynamic Indexes) indexes were used: neurological (NEUR), Mayer (MAYER), respiratory (RESP), and pulse (PULSE) ones. The HRV indexes included HR (Heart Rate), PWR (Power, total oscillation power), LF (Low Frequency), HF (High Frequency), SDNN (Standard Deviation of the Normal-to-Normal), RMSSD (Root Mean Square of the Successive Differences). CVI (Cardiac Vagal Index), and CSI (Cardiac Sympathetic Index). Results. In women who were on drug therapy alone (EH-1), negative relationships were found for LF and LF/HF with systolic, mean and pulse pressure. For EH-2, PWR, LF, and HF negatively correlated with pulse pressure. For EH-1, HR positively correlated with the hemodynamic indices HI1 and RHI2 and negatively correlated with RHI3; RMSSD negatively correlated with RHI3; and HF negatively correlated with HI1/HI3. For patients with EH-2, negative correlations were observed for SDNN and RHI1, PWR and RHI1; positive correlations were found between PWR and HI2; HI3, RHI2, HF and RHI3; and between LF/HF and HI1/HI3. HF negatively correlated with HI1/HI3 and with RHI1. LF/HF negatively correlated with RHI3, and CSI negatively correlated with RHI3. In patients with EH-1, SDNN, PWR, LF, HF, CVI, and NEUR_HI1 were directly related, which indicated an effect of these factors on the endothelial blood flow (HI1). In the EH-2 group, only positive correlations were found between LF, HF, and NEUR_HI3. In EH-1 patients, all oscillatory rhythms influenced BP; this influence could be both negative (for MAYER_HI1, PULSE_HI2) and positive (for MAYER_HI2, RESP_HI3). In EH-2 patients, no relationship was found between blood pressure and oscillatory indices. Conclusion. The smaller number of factors influencing blood pressure and hemodynamics in the EH-2 group compared to the EH-1 group was more beneficial and favorable, which ensured faster and steadier normalization of blood pressure.

“The immediate effect of neutral spinal compress on heart rate variability in hypertensive individuals”

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Poornima Bansal ◽  
Sujatha Kannarpady Janardan ◽  
Prashanth Shetty
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Conventional Medicine ◽  
Medical Condition ◽  
Low Frequency ◽  
Chronic Medical Condition ◽  
Clinical Trial Registry ◽  
And Shifts

Abstract Objectives Hypertension (HTN) is considered as chronic medical condition. Because of the increased complications associated with the conventional medicine, the effects of naturopathic modalities were emphasized to prevent and minimize those adverse effects. This study was done to assess the immediate effect of neutral spinal compress on heart rate variability and blood pressure and thereby to substantiate the clinical understanding of its effect in hypertensive individuals. Methods Hundred hypertensive individuals were recruited for the study. Subjects were assessed for Blood Pressure (BP) and Heart Rate Variability (HRV) before and immediately after the intervention of 20 min. Results Result shows significant reduction in mean Heart Rate (HR) (p<0.001), Low Frequency (LF) (p<0.001), Low Frequency/High Frequency (LF/HF) (p<0.001), Systolic blood pressure (SBP) (p<0.001) and Diastolic blood pressure (DBP) (p<0.001) and significant increase in mean R-R interval (Mean RR) (p<0.001) and High frequency (HF) (p<0.001) components of Heart Rate Variability after neutral spinal compress intervention. Conclusions The results of the study reported that full neutral spinal compress reduces the sympathetic tone and shifts the Sympatho-vagal balance in favor of parasympathetic dominance and hence it can be concluded that neutral spinal compress can be effectively used in the management of hypertension. Trial registration Clinical Trial Registry- India (CTRI); CTRI Reg. No- CTRI/2020/01/022639.

Differential Effects of Propofol and Sevoflurane on Heart Rate Variability

2003 ◽  
Vol 98 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Noriaki Kanaya ◽  
Naoyuki Hirata ◽  
Saori Kurosawa ◽  
Masayasu Nakayama ◽  
Akiyoshi Namiki
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Maximum Entropy Method ◽  
Low Frequency ◽  
Entropy Method ◽  
Dependent Manner ◽  
Different Depths ◽  
Parasympathetic Tone

Background Propofol is reported to reduce both sympathetic and parasympathetic tone; however, it is not clear whether the changes in heart rate variability are associated with depth of anesthesia. The purposes of the present study were (1) to evaluate the changes in heart rate variability at different depths of hypnosis and (2) to compare the effects of propofol on heart rate variability with that of sevoflurane. Methods Thirty patients were randomly allocated into the propofol or sevoflurane for induction of anesthesia. The depth of hypnosis was monitored by the Bispectral Index (BIS). Spectral analysis of heart rate variability using a maximum-entropy method resulted in a characteristic power spectrum with two main regions, a high frequency (HF) and a low frequency (LF). Hemodynamics, entropy, LF, HF, and LF/HF were monitored when the patients were awake and after induction of anesthesia. Results Both propofol and sevoflurane decreased blood pressure in a BIS-dependent manner, whereas heart rate showed no significant changes during the study period. In the propofol group, entropy and HF decreased with a reduction in the BIS value. Although LF decreased after induction of anesthesia, propofol caused no further decrease in LF in spite of a reduction in the BIS value. In the sevoflurane group, LF decreased with a reduction in the BIS value. Entropy and HF decreased after induction of anesthesia (BIS at 80); however, no further decreases were observed in spite of a reduction in the BIS value. Conclusions Induction of anesthesia with propofol decreased blood pressure, entropy, and HF in a BIS-dependent manner, indicating that propofol reduces cardiac parasympathetic tone depending on the depth of hypnosis. Conversely, sevoflurane did not show the BIS-dependent decreases in heart rate, blood pressure, HF, and entropy, indicating that sevoflurane has little or no effect on cardiac parasympathetic tone.

Coarse-graining spectral analysis: new method for studying heart rate variability

1991 ◽  
Vol 71 (3) ◽  
pp. 1143-1150 ◽  
Author(s):  
Y. Yamamoto ◽  
R. L. Hughson
Keyword(s):  
Heart Rate ◽  
Time Series ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
High Frequency ◽  
Low Frequency ◽  
Scale Invariant ◽  
Very Low Frequency ◽  
Frequency Components ◽  
Harmonic Components

Heart rate variability (HRV) spectra are typically analyzed for the components related to low- (less than 0.15 Hz) and high- (greater than 0.15 Hz) frequency variations. However, there are very-low-frequency components with periods up to hours in HRV signals, which might smear short-term spectra. We developed a method of spectral analysis suitable for selectively extracting very-low-frequency components, leaving intact the low- and high-frequency components of interest in HRV spectral analysis. Computer simulations showed that those low-frequency components were well characterized by fractional Brownian motions (FBMs). If the scale invariant, or self-similar, property of FBMs is considered a new time series (x′) was constructed by sampling only every other point (course graining) of the original time series (x). Evaluation of the cross-power spectra between these two (Sxx′) showed that the power of the FBM components was preserved, whereas that of the harmonic components vanished. Subtraction of magnitude of Sxx from the autopower spectra of the original sequence emphasized only the harmonic components. Application of this method to HRV spectral analyses indicated that it might enable one to observe more clearly the low- and high-frequency components characteristic of autonomic control of heart rate.

Effect of hot arm and foot bath on heart rate variability and blood pressure in healthy volunteers

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Samruddhi Chintaman Vyas ◽  
A. Mooventhan ◽  
N. K. Manjunath
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Volunteers ◽  
High Frequency ◽  
Low Frequency ◽  
Healthy Male ◽  
Before And After ◽  
Instantaneous Heart Rate ◽  
The Mean

AbstractBackgroundThough hot arm and foot bath (HAFB) is widely used, a precise physiological response is not reported. Hence, the present study was conducted to evaluate the effect of HAFB on heart rate variability (HRV) and blood pressure (BP) in healthy volunteers.Materials and MethodsSixteen healthy male volunteers’ aged 23.81 ± 5.27 (mean ± standard deviation) years were recruited. All the subjects underwent only one session of HAFB (104-degree Fahrenheit) for the duration of 20 min. Assessments such as Electrocardiography and BP were taken before and after the intervention.ResultsResults of this study showed a significant reduction in systolic-BP (SBP), diastolic-BP (DBP), mean arterial pressure (MAP), the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (RR interval), the number of interval differences of successive NN intervals greater than 50 ms (NN50), the proportion derived by dividing NN50 by the total number of NN intervals (pNN50), and high frequency (HF) band of HRV along with a significant increase in heart rate (HR), low-frequency (LF) band of HRV and LF/HF ratio compared to its baseline.ConclusionsResults of this study suggest that 20 min of HAFB produce a significant increase in HR and a significant reduction in SBP, DBP, and MAP while producing parasympathetic withdrawal.

Impact of Changes in Respiratory Frequency and Posture on Power Spectral Analysis of Heart Rate and Systolic Blood Pressure Variability in Normal Subjects and Patients with Heart Failure

1996 ◽  
Vol 91 (1) ◽  
pp. 35-43 ◽  
Author(s):  
John E. Sanderson ◽  
Leata Y. C. Yeung ◽  
Dickens T. K. Yeung ◽  
Richard L. C. Kay ◽  
Brian Tomlinson ◽  
...  
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Heart Rate ◽  
Spectral Analysis ◽  
High Frequency ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Normal Subjects ◽  
Power Spectral ◽  
Patients With Heart Failure

1. Autonomic dysfunction is a major feature of congestive cardiac failure and may have an important role in determining progression and prognosis. The low-frequency/high-frequency ratio derived from power spectral analysis of heart rate variability has been proposed as a non-invasive method to assess sympatho-vagal balance. However, the effects of different respiratory rates or posture are rarely accounted for, but may be relevant in patients with heart failure in whom clinical improvement is accompanied by a fall in respiratory rate and an increased proportion of the day in the upright position. 2. We have assessed the effect of controlled respiration at different rates (10, 15, 20 breaths/min or 0.17, 0.25 and 0.33 Hz), while supine and standing, on power spectral analysis of heart rate and blood pressure variability in 11 patients with heart failure and 10 normal subjects. 3. Heart rate variance and low-frequency power (normalized units) were reduced in patients with heart failure (absent in six). During controlled breathing while supine, the power of the high-frequency component was significantly greater at 10 breaths/min than at 20 breaths/min in patients with heart failure, whether expressed in absolute units (P = 0.005) or percentage of total power (P = 0.03). 4. On standing, controlled breathing in patients with heart failure produced less change in high-frequency power (P = 0.054), but the low-frequency/high-frequency ratio at lower respiratory rates was reduced (P = 0.05). In normal subjects, as expected, respiratory rate had a highly significant effect on high-frequency power. Also, in normal subjects there was the expected increase in heart rate low-frequency power (P = 0.04) moving from supine to standing with an increase in the low-frequency/high-frequency ratio (P = 0.003), while in the patients with heart failure this was absent, reflecting blunted cardiovascular reflexes. 5. Systolic blood pressure low- and high-frequency components and their ratio were significantly affected by respiration (P > 0.03) and change in posture (P > 0.03) in both patients with heart failure and normal subjects, with a significant increase in the low-frequency/high-frequency ratio (P = 0.03) on standing in patients with heart failure, indicating that autonomic modulation of blood pressure is still operating in heart failure. 6. Thus, respiratory rate and changes in posture have a significant effect on measurements derived from spectral analysis of heart rate and blood pressure variability. Studies that use power spectral analysis as a measure of sympatho-vagal balance should control for these variables.

scholarly journals Even slight movements disturb analysis of cardiovascular dynamics

1999 ◽  
Vol 277 (1) ◽  
pp. H261-H267 ◽  
Author(s):  
Jacques-Olivier Fortrat ◽  
Cédric Formet ◽  
Jean Frutoso ◽  
Claude Gharib
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Low Frequency ◽  
Coarse Graining ◽  
Spectral Exponent ◽  
Spontaneous Movements ◽  
Frequency Components ◽  
Fractal Noise

We hypothesized that spontaneous movements (postural adjustments and ideomotion) disturb analysis of heart rate and blood pressure variability and could explain the discrepancy between studies. We measured R-R intervals and systolic blood pressure in nine healthy sitting subjects during three protocols: 1) no movement allowed, 2) movements allowed but not standing, 3) movements and standing allowed. Heart rate and blood pressure were not altered by movements. Movements with or without standing produced a twofold or greater increase of the overall variability of R-R intervals and of the low-frequency components of spectral analysis of heart rate variability. The spectral exponent β of heart rate variability (1.123 at rest) was changed by movements (1.364), and the percentage of fractal noise (79% at rest) was increased by standing (91%, coarse-graining spectral analysis). Spontaneous movements could induce a plateau in the correlation dimensions of heart rate variability, but they changed its nonlinear predictability. We suggest that future studies on short-term cardiovascular variability should control spontaneous movements.

scholarly journals Effect of Global Postural Reeducation on cardiovascular system of healthy subjects

2014 ◽  
Vol 27 (3) ◽  
pp. 389-397 ◽  
Author(s):  
Elizângela Márcia de Carvalho Abreu ◽  
Tatiana Sousa Cunha ◽  
Alderico Rodrigues de Paula Júnior ◽  
Marco Antonio de Oliveira
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Wavelet Transform ◽  
Cardiovascular System ◽  
High Frequency ◽  
Sympathetic Activity ◽  
Healthy Subjects ◽  
Low Frequency ◽  
Healthy Men

Objective To evaluate the effect of Global Postural Reeducation (GPR) on cardiovascular system by heart rate variability (HRV), blood pressure (BP) and heart rate (HR). Materials and methods Seventeen healthy men (22.47 ± 3.02 years) were submitted to the postures frog on the floor, frog on the air, sitting, standing against the wall and inclined standing, two postures per session. The systolic and diastolic blood pressure (SBP and DBP) and HR were recorded. The intervals between heartbeats were collected during the whole session (Polar S810i). The frequency domain was analyzed (Wavelet Transform), the low frequency (LF) and high frequency (HF) were obtained. The data were analyzed by ANOVA and Tukey (p < 0.05). Results Increased LF/HF ratio was observed in the frog on the floor (1 ± 0.1 vs. 2 ± 0.3 p < 0.05) and on the air postures (1 ± 0.1 vs. 2 ± 0.2 p < 0.01). There was an increase in SBP in the postures frog on the floor (123 ± 2 vs. 136 ± 4 p < 0.05), frog on the air (122 ± 2 vs. 133 ± 3 p < 0.05), standing against the wall (123 ± 2 vs. 136 ± 4 p < 0.05), inclined standing (124 ± 3 vs. 146 ± 5 p < 0.05). There was increase of DBP in the postures frog on the floor (69 ± 2 vs. 81 ± 2 p < 0.01), frog on the air (72 ± 2 vs. 83 ± 3 p < 0.05), sitting (85 ± 2 vs. 102 ± 3 p < 0.01). There was increase in HR in the postures frog on the air (67 ± 2 vs. 77 ± 3 p < 0.05) and inclined standing (88 ± 3.5 vs. 101 ± 3 p < 0.05). Conclusion The increase in LF/HF ratio and also the BP and HR indicates high sympathetic activity, possibly related to the work isometric developed during GPR method. [P]

Autonomic control of heart rate during exercise studied by heart rate variability spectral analysis

1991 ◽  
Vol 71 (3) ◽  
pp. 1136-1142 ◽  
Author(s):  
Y. Yamamoto ◽  
R. L. Hughson ◽  
J. C. Peterson
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
High Frequency ◽  
Parasympathetic Nervous System ◽  
Ventilatory Threshold ◽  
Power Spectra ◽  
Low Frequency ◽  
Exercise Tests ◽  
Alveolar Gas Exchange

Spectral analysis of heart rate variability (HRV) might provide an index of relative sympathetic (SNS) and parasympathetic nervous system (PNS) activity during exercise. Eight subjects completed six 17-min submaximal exercise tests and one resting measurement in the upright sitting position. During submaximal tests, work rate (WR) was increased for the initial 3 min in a ramp fashion until it reached constant WRs of 20 W, or 30, 60, 90, 100, and 110% of the predetermined ventilatory threshold (Tvent). Ventilatory profile and alveolar gas exchange were monitored breath by breath, and beat-to-beat HRV was measured as R-R intervals of an electrocardiogram. Spectral analysis was applied to the HRV from 7 to 17 min. Low-frequency (0–0.15 Hz) and high-frequency (0.15–1.0 Hz) areas under power spectra (LO and HI, respectively) were calculated. The indicator of PNS activity (HI) decreased dramatically (P less than 0.05) when the subjects exercised compared with rest and continued to decrease until the intensity reached 60% Tvent. The indicator of SNS activity (LO/HI) remained unchanged up to 100% Tvent, whereas it increased abruptly (P less than 0.05) at 110% Tvent. The results suggested that (cardiac) PNS activity decreased progressively from rest to a WR equivalent to 60% Tvent, and SNS activity increased only when exercise intensity exceeded Tvent.

Sign in / Sign up

Export Citation Format

Share Document