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Consulta: subjectFacets:"Heart rate variability"
Registros recuperados: 22
Data/hora: 09/06/2017 09:44:07
Circadian cardiac autonomic function in perinatally HIV-infected preschool children
Provedor de dados: 56
Autores: Benchimol-Barbosa,P.R.
The 24-h heart rate variability and QT-interval adaptation was investigated in perinatally HIV-infected preschool children
classified according to immunological status in order to assess autonomic function at early stages of infection. Thirty-five
perinatally HIV-infected and clinically stable children (4.8 ± 0.3 years) were enrolled after approval of the study by the University
Hospital Pedro Ernesto Ethics Committee and written informed parental consent was obtained. The children were classified
according to peripheral CD4+ count (cells/µL) as follows: group 1, N = 11 (≥1000); group 2, N = 7
(≥500 and <1000); group 3, N = 17 (<500). Left ventricular ejection fraction (>55%), 24-h RR interval
variability (RRV) indexes (NN,...
Tipo: Journal article
Palavras-chave: Autonomic nervous system; Circadian rhythm; Heart rate variability; Human immunodeficiency virus infection;
Perinatally HIV-infected children.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000800006
Effects of aerobic exercise training on heart rate variability during wakefulness and sleep and
cardiorespiratory responses of young and middle-aged healthy men
Provedor de dados: 56
Autores: Catai,A.M.; Chacon-Mikahil,M.P.T.; Martinelli,F.S.; Forti,V.A.M.; Silva,E.; Golfetti,R.; Martins,L.E.B.; Szrajer,J.S.;
Wanderley,J.S.; Lima-Filho,E.C.; Milan,L.A.; Marin-Neto,J.A.; Maciel,B.C.; Gallo-Junior,L.
The purpose of the present study was to evaluate the effects of aerobic physical training (APT) on heart rate variability (HRV) and
cardiorespiratory responses at peak condition and ventilatory anaerobic threshold. Ten young (Y: median = 21 years) and seven
middle-aged (MA = 53 years) healthy sedentary men were studied. Dynamic exercise tests were performed on a cycloergometer
using a continuous ramp protocol (12 to 20 W/min) until exhaustion. A dynamic 24-h electrocardiogram was analyzed by time
(TD) (standard deviation of mean R-R intervals) and frequency domain (FD) methods. The power spectral components were
expressed as absolute (a) and normalized units (nu) at low (LF) and high (HF) frequencies and as the LF/HF ratio. Control (C)
condition: HRV in TD...
Tipo: Journal article
Palavras-chave: Heart rate variability; Power spectral density analysis; Anaerobic threshold; Aerobic exercise training;
Autonomic nervous system and aging processes in man.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000600016
Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a
postural change maneuver
Provedor de dados: 56
Autores: Dantas,E.M.; Gonçalves,C.P.; Silva,A.B.T.; Rodrigues,S.L.; Ramos,M.S.; Andreão,R.V.; Pimentel,E.B.; Lunz,W.;
Mill,J.G.
Heart rate variability (HRV) provides important information about cardiac autonomic modulation. Since it is a noninvasive and
inexpensive method, HRV has been used to evaluate several parameters of cardiovascular health. However, the internal
reproducibility of this method has been challenged in some studies. Our aim was to determine the intra-individual reproducibility
of HRV parameters in short-term recordings obtained in supine and orthostatic positions. Electrocardiographic (ECG) recordings
were obtained from 30 healthy subjects (20-49 years, 14 men) using a digital apparatus (sampling ratio = 250 Hz). ECG was
recorded for 10 min in the supine position and for 10 min in the orthostatic position. The procedure was repeated 2-3 h later. Time
and...
Tipo: Journal article
Palavras-chave: Heart rate variability; Power spectral analysis; Reproducibility; Autonomic nervous system.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010001000010
Ovariectomy does not affect the cardiac sympathovagal balance of female SHR but estradiol does
Provedor de dados: 56
Autores: Dias,D.P.M.; Oliveira,M.; Salgado,H.C.; Fazan Jr.,R.
The low incidence of cardiovascular diseases, including hypertension, in premenopausal women has led to the conclusion that
ovarian hormones may have a protective effect on the cardiovascular system. We evaluated the effects of ovariectomy and/or
estradiol on sympathovagal balance and heart rate variability (HRV) in female spontaneously hypertensive rats (SHR) with
tachycardia and compared them to Wistar rats (12 weeks old; N = 8-12). Ovariectomy (OVX) and/or estradiol (10 µg/kg) did not
affect basal arterial pressure in either rat strain, but estradiol increased basal heart rate (HR) in OVX SHR (454 ± 18 vs 377 ± 9
bpm). HR changes elicited by methylatropine and propranolol were used to evaluate the sympathovagal balance. Ovariectomy did
not affect the...
Tipo: Journal article
Palavras-chave: Estrogen; SHR; Heart rate variability; Hypertension; Sympathovagal balance.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010001000008
Reliability and validity of heart rate variability threshold assessment during an incremental
shuttle-walk test in middle-aged and older adults
Provedor de dados: 56
Autores: Dourado,V.Z.; Guerra,R.L.F.
Studies on the assessment of heart rate variability threshold (HRVT) during walking are scarce. We determined the reliability and
validity of HRVT assessment during the incremental shuttle walk test (ISWT) in healthy subjects. Thirty-one participants aged 57
± 9 years (17 females) performed 3 ISWTs. During the 1st and 2nd ISWTs, instantaneous heart rate variability was calculated
every 30 s and HRVT was measured. Walking velocity at HRVT in these tests (WV-HRVT1 and WV-HRVT2) was registered.
During the 3rd ISWT, physiological responses were assessed. The ventilatory equivalents were used to determine ventilatory
threshold (VT) and the WV at VT (WV-VT) was recorded. The difference between WV-HRVT1 and WV-HRVT2 was not
statistically significant (median and...
Tipo: Journal article
Palavras-chave: Heart rate variability; Exercise; Walking; Adults.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2013000200194
A comparative analysis of preprocessing techniques of cardiac event series for the study of heart
rhythm variability using simulated signals
Provedor de dados: 56
Autores: Guimarães,H.N.; Santos,R.A.S.
In the present study, using noise-free simulated signals, we performed a comparative examination of several preprocessing
techniques that are used to transform the cardiac event series in a regularly sampled time series, appropriate for spectral analysis
of heart rhythm variability (HRV). First, a group of noise-free simulated point event series, which represents a time series of
heartbeats, was generated by an integral pulse frequency modulation model. In order to evaluate the performance of the
preprocessing methods, the differences between the spectra of the preprocessed simulated signals and the true spectrum (spectrum
of the model input modulating signals) were surveyed by visual analysis and by contrasting merit indices. It is desired that
estimated...
Tipo: Journal article
Palavras-chave: Heart rhythm variability; Heart rate variability; Spectral analysis; Data preprocessing; Integral pulse frequency
modulation model.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000300015
Heart rate recovery after exercise: relations to heart rate variability and complexity
Provedor de dados: 56
Autores: Javorka,M.; Zila,I.; Balhárek,T.; Javorka,K.
Physical exercise is associated with parasympathetic withdrawal and increased sympathetic activity resulting in heart rate
increase. The rate of post-exercise cardiodeceleration is used as an index of cardiac vagal reactivation. Analysis of heart rate
variability (HRV) and complexity can provide useful information about autonomic control of the cardiovascular system. The aim
of the present study was to ascertain the association between heart rate decrease after exercise and HRV parameters. Heart rate
was monitored in 17 healthy male subjects (mean age: 20 years) during the pre-exercise phase (25 min supine, 5 min standing),
during exercise (8 min of the step test with an ascending frequency corresponding to 70% of individual maximal power output)
and...
Tipo: Journal article
Palavras-chave: Exercise recovery; Heart rate variability; Entropy; Spectral analysis; Parasympathetic system.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000800018
Linear and nonlinear analysis of heart rate variability in healthy subjects and after acute myocardial
infarction in patients
Provedor de dados: 56
Autores: Kunz,V.C.; Borges,E.N.; Coelho,R.C.; Gubolino,L.A.; Martins,L.E.B.; Silva,E.
The objectives of this study were to evaluate and compare the use of linear and nonlinear methods for analysis of heart rate
variability (HRV) in healthy subjects and in patients after acute myocardial infarction (AMI). Heart rate (HR) was recorded for 15
min in the supine position in 10 patients with AMI taking β-blockers (aged 57 ± 9 years) and in 11 healthy subjects
(aged 53 ± 4 years). HRV was analyzed in the time domain (RMSSD and RMSM), the frequency domain using low- and
high-frequency bands in normalized units (nu; LFnu and HFnu) and the LF/HF ratio and approximate entropy (ApEn) were
determined. There was a correlation (P < 0.05) of RMSSD, RMSM, LFnu, HFnu, and the LF/HF ratio index with the ApEn of
the AMI group on the 2nd (r = 0.87,...
Tipo: Journal article
Palavras-chave: Myocardial infarction; Heart rate variability; Autonomic nervous system; Spectral analysis; Nonlinear dynamics.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000500011
Cardiac autonomic modulation during progressive upper limb exercise by patients with coronary
artery disease
Provedor de dados: 56
Autores: Machado,H.G.; Simões,R.P.; Mendes,R.G.; Castello,V.; Di Thommazo,L.; Almeida,L.B.; Lopes,S.L.B.; Catai,A.M.;
Borghi-Silva,A.
The purpose of this study was to investigate the behavior of heart rate (HR) and HR variability (HRV) during different loads of
resistance exercise (incline bench press) in patients with coronary artery disease (CAD) and healthy sedentary controls. Ten
healthy men (65 ± 1.2 years, control group, CG) and 10 men with clinically stable CAD (66 ± 2.4 years, CADG) were recruited. A
discontinuous progressive protocol was applied with an initial load of 10% of the maximum load achieved in the 1RM (1
repetition maximum) with increases of 10% until 30% 1RM was reached, which was followed by subsequent increases of 5%
1RM until exhaustion. HRV was analyzed by linear and non-linear methods. There was a significant reduction in rMSSD (CG: 20
± 2 to 11 ± 3 ms; CADG: 19...
Tipo: Journal article
Palavras-chave: Dynamic resistance exercise; Coronary artery disease; Heart rate variability; Autonomic nervous system; Upper
limb exercise.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011001200012
Heart rate variability in athletes and nonathletes at rest and during head-up tilt
Provedor de dados: 56
Autores: Martinelli,F.S.; Chacon-Mikahil,M.P.T.; Martins,L.E.B.; Lima-Filho,E.C.; Golfetti,R.; Paschoal,M.A.; Gallo-Junior,L.
The purpose of the present study was to determine if autonomic heart rate modulation, indicated by heart rate variability (HRV),
differs during supine rest and head-up tilt (HUT) when sedentary and endurance-trained cyclists are compared. Eleven sedentary
young men (S) and 10 trained cyclists (C) were studied. The volunteers were submitted to a dynamic ECG Holter to calculate
HRV at rest and during a 70º HUT. The major aerobic capacity of athletes was expressed by higher values of <img
src="/img/revistas/bjmbr/v38n4/Vo.gif">at anaerobic threshold and peak conditions (P < 0.05). At rest the athletes had
lower heart rates (P < 0.05) and higher values in the time domain of HRV compared with controls (SD of normal RR interval,
SDNN, medians): 59.1...
Tipo: Journal article
Palavras-chave: Endurance; Power spectral analysis; Heart rate variability; Autonomic heart rate modulation; Training
bradycardia; Orthostatic stress.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000400019
Pulmonary function, cholinergic bronchomotor tone, and cardiac autonomic abnormalities in type 2
diabetic patients
Provedor de dados: 56
Autores: Melo,E.; Vianna,E.O.; Gallo Jr.,L.; Foss,M.C.; Terra-Filho,J.
This prospective study analyzed the involvement of the autonomic nervous system in pulmonary and cardiac function by
evaluating cardiovascular reflex and its correlation with pulmonary function abnormalities of type 2 diabetic patients. Diabetic
patients (N = 17) and healthy subjects (N = 17) were evaluated by 1) pulmonary function tests including spirometry, He-dilution
method, N2 washout test, and specific airway conductance (SGaw) determined by plethysmography before and after aerosol
administration of atropine sulfate, and 2) autonomic cardiovascular activity by the passive tilting test and the magnitude of
respiratory sinus arrhythmia (RSA). Basal heart rate was higher in the diabetic group (87.8 ± 11.2 bpm; mean ± SD) than in the
control group (72.9...
Tipo: Journal article
Palavras-chave: Diabetes mellitus; Autonomic nervous system; Autonomic neuropathy; Heart rate variability; Blood pressure
variability.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000300002
Effects of age and physical activity on the autonomic control of heart rate in healthy men
Provedor de dados: 56
Autores: Melo,R.C.; Santos,M.D.B.; Silva,E.; Quitério,R.J.; Moreno,M.A.; Reis,M.S.; Verzola,I.A.; Oliveira,L.; Martins,L.E.B.;
Gallo-Junior,L.; Catai,A.M.
The effects of the aging process and an active life-style on the autonomic control of heart rate (HR) were investigated in nine
young sedentary (YS, 23 ± 2.4 years), 16 young active (YA, 22 ± 2.1 years), 8 older sedentary (OS, 63 ± 2.4 years) and 8 older
active (OA, 61 ± 1.1 years) healthy men. Electrocardiogram was continuously recorded for 15 min at rest and for 4 min in the
deep breathing test, with a breath rate of 5 to 6 cycles/min in the supine position. Resting HR and RR intervals were analyzed by
time (RMSSD index) and frequency domain methods. The power spectral components are reported in normalized units (nu) at low
(LF) and high (HF) frequency, and as the LF/HF ratio. The deep breathing test was analyzed by the respiratory sinus arrhythmia...
Tipo: Journal article
Palavras-chave: Heart rate variability; Respiratory sinus arrhythmia; Autonomic nervous system; Aging process; Aerobic
exercise.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000900007
Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate
variability
Provedor de dados: 56
Autores: Migliaro,E.R.; Contreras,P.; Bech,S.; Etxagibel,A.; Castro,M.; Ricca,R.; Vicente,K.
In order to assess the relative influence of age, resting heart rate (HR) and sedentary life style, heart rate variability (HRV) was
studied in two different groups. The young group (YG) consisted of 9 sedentary subjects aged 15 to 20 years (YG-S) and of 9
nonsedentary volunteers (YG-NS) also aged 15 to 20. The elderly sedentary group (ESG) consisted of 16 sedentary subjects aged
39 to 82 years. HRV was assessed using a short-term procedure (5 min). R-R variability was calculated in the time-domain by
means of the root mean square successive differences. Frequency-domain HRV was evaluated by power spectrum analysis
considering high frequency and low frequency bands. In the YG the effort tolerance was ranked in a bicycle stress test. HR was
similar for both...
Tipo: Journal article
Palavras-chave: Heart rate variability; Short-term analysis; Autonomic nervous system; Aging; Sedentary life style.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000400009
Analysis of heart rate control to assess thermal sensitivity responses in Brazilian toads
Provedor de dados: 56
Autores: Natali,J.E.S.; Santos,B.T.; Rodrigues,V.H.; Chauí-Berlinck,J.G.
In anurans, changes in ambient temperature influence body temperature and, therefore, energy consumption. These changes
ultimately affect energy supply and, consequently, heart rate (HR). Typically, anurans living in different thermal environments
have different thermal sensitivities, and these cannot be distinguished by changes in HR. We hypothesized that Rhinella jimi (a
toad from a xeric environment that lives in a wide range of temperatures) would have a lower thermal sensitivity regarding cardiac
control than R. icterica (originally from a tropical forest environment with a more restricted range of ambient temperatures).
Thermal sensitivity was assessed by comparing animals housed at 15° and 25°C. Cardiac control was
estimated by...
Tipo: Journal article
Palavras-chave: Anuran; Cardiac control; Heart rate complexity; Heart rate variability; Thermal physiology.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2015000100046
Autonomic modulation of heart rate of young and postmenopausal women undergoing estrogen
therapy
Provedor de dados: 56
Autores: Neves,V.F.C.; Silva de Sá,M.F.; Gallo Jr.,L.; Catai,A.M.; Martins,L.E.B.; Crescêncio,J.C.; Perpétuo,N.M.; Silva,E.
The aim of the present study was to determine whether estrogen therapy (ET) reduces alterations of the autonomic control of heart
rate (HR) due to hypoestrogenism and aging. Thirteen young (24 ± 2.6 years), 10 postmenopausal (53 ± 4.6 years) undergoing ET
(PM-ET), and 14 postmenopausal (56 ± 2.6 years) women not undergoing ET (PM) were studied. ET consisted of 0.625 mg/day
conjugated equine estrogen. HR was recorded continuously for 8 min at rest in the supine and sitting positions. HR variability
(HRV) was analyzed by time (SDNN and rMSSD indices) and frequency domain methods. Power spectral components are
reported as normalized units (nu) at low (LF) and high (HF) frequencies, and as LF/HF ratio. Intergroup comparisons: SDNN
index was higher in young...
Tipo: Journal article
Palavras-chave: Heart rate variability; Aging; Menopause; Estrogen therapy.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007000400007
Noninvasive method for electrocardiogram recording in conscious rats: feasibility for heart rate
variability analysis
Provedor de dados: 42
Autores: Pereira-Junior,Pedro P.; Marocolo,Moacir; Rodrigues,Fabricio P.; Medei,Emiliano; Nascimento,José H.M.
Heart rate variability (HRV) analysis consists in a well-established tool for the assessment of cardiac autonomic control, both in
humans and in animal models. Conventional methods for HRV analysis in rats rely on conscious state electrocardiogram (ECG)
recording based on prior invasive surgical procedures for electrodes/transmitters implants. The aim of the present study was to test
a noninvasive and inexpensive method for ECG recording in conscious rats, assessing its feasibility for HRV analysis. A
custom-made elastic cotton jacket was developed to fit the rat's mean thoracic circumference, with two pieces of platinum
electrodes attached on its inner surface, allowing ECG to be recorded noninvasively in conscious, restrained rats (n=6). Timeand...
Tipo: Journal article
Palavras-chave: Electrocardiography; Heart rate variability; Methodology; Noninvasive; Rat.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000200019
Spectral and symbolic analysis of the effect of gender and postural change on cardiac autonomic
modulation in healthy elderly subjects
Provedor de dados: 56
Autores: Perseguini,N.M.; Takahashi,A.C.M.; Rebelatto,J.R.; Silva,E.; Borghi-Silva,A.; Porta,A.; Montano,N.; Catai,A.M.
The objective of this study was to use linear and non-linear methods to investigate cardiac autonomic modulation in healthy
elderly men and women in response to a postural change from the supine to the standing position. Fourteen men (66.1 ± 3.5 years)
and 10 women (65.3 ± 3.3 years) were evaluated. Beat-to-beat heart rate was recorded in the supine and standing positions. Heart
rate variability was studied by spectral analysis, including both low (LFnu-cardiac sympathetic modulation (CSM) indicator) and
high (HFnu-cardiac vagal modulation (CVM) indicator) frequencies in normalized units as well as the low frequency/high
frequency (LF/HF) ratio. Symbolic analysis was performed using the following indexes: 0V% (CSM indicator), 1V% (CSM and
CVM indicators),...
Tipo: Journal article
Palavras-chave: Heart rate variability; Autonomic nervous system; Symbolic analysis; Spectral analysis; Elderly; Gender.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000100005
Heart rate variability under resting conditions in postmenopausal and young women
Provedor de dados: 56
Autores: Ribeiro,T.F.; Azevedo,G.D.; Crescêncio,J.C.; Marães,V.R.F.S.; Papa,V.; Catai,A.M.; Verzola,R.M.M.; Oliveira,L.;
Silva de Sá,M.F.; Gallo Jr.,L.; Silva,E.
The aim of the present study was to compare the modulation of heart rate in a group of postmenopausal women to that of a group
of young women under resting conditions on the basis of R-R interval variability. Ten healthy postmenopausal women (mean ±
SD, 58.3 ± 6.8 years) and 10 healthy young women (mean ± SD, 21.6 ± 0.82 years) were submitted to a control resting
electrocardiogram (ECG) in the supine and sitting positions over a period of 6 min. The ECG was obtained from a one-channel
heart monitor at the CM5 lead and processed and stored using an analog to digital converter connected to a microcomputer. R-R
intervals were calculated on a beat-to-beat basis from the ECG recording in real time using a signal-processing software. Heart
rate variability (HRV)...
Tipo: Journal article
Palavras-chave: Heart rate variability; Menopause; Autonomic nervous system; Time domain indexes.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000700006
Relationship between cardiovascular dysfunction and hyperglycemia in streptozotocin-induced
diabetes in rats
Provedor de dados: 56
Autores: Schaan,B.D.; Dall'Ago,P.; Maeda,C.Y.; Ferlin,E.; Fernandes,T.G.; Schmid,H.; Irigoyen,M.C.
Streptozotocin (STZ)-induced diabetes in rats is characterized by cardiovascular dysfunction beginning 5 days after STZ injection,
which may reflect functional or structural autonomic nervous system damage. We investigated cardiovascular and autonomic
function, in rats weighing 166 ± 4 g, 5-7, 14, 30, 45, and 90 days after STZ injection (N = 24, 33, 27, 14, and 13, respectively).
Arterial pressure (AP), mean AP (MAP) variability (standard deviation of the mean of MAP, SDMMAP), heart rate (HR), HR
variability (standard deviation of the normal pulse intervals, SDNN), and root mean square of successive difference of pulse
intervals (RMSSD) were measured. STZ induced increased glycemia in diabetic rats vs control rats. Diabetes reduced resting HR
from 363 ± 12...
Tipo: Journal article
Palavras-chave: Diabetes; Streptozotocin; Heart rate variability; Rats; Autonomic nervous system; Arterial pressure variability.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004001200016
Comparison of the Polar S810i monitor and the ECG for the analysis of heart rate variability in the
time and frequency domains
Provedor de dados: 56
Autores: Vanderlei,L.C.M.; Silva,R.A.; Pastre,C.M.; Azevedo,F.M.; Godoy,M.F.
The aim of the present study was to compare heart rate variability (HRV) at rest and during exercise using a temporal series
obtained with the Polar S810i monitor and a signal from a LYNX® signal conditioner (BIO EMG 1000 model) with a channel
configured for the acquisition of ECG signals. Fifteen healthy subjects aged 20.9 ± 1.4 years were analyzed. The subjects
remained at rest for 20 min and performed exercise for another 20 min with the workload selected to achieve 60% of submaximal
heart rate. RR series were obtained for each individual with a Polar S810i instrument and with an ECG analyzed with a biological
signal conditioner. The HRV indices (rMSSD, pNN50, LFnu, HFnu, and LF/HF) were calculated after signal processing and
analysis. The unpaired...
Tipo: Journal article
Palavras-chave: Heart rate variability; Autonomic nervous system; Exercise; Spectral analysis; ECG; Polar S810i monitor.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008001000004
Altered heart rate and blood pressure variability in mice lacking the Mas protooncogene
Provedor de dados: 56
Autores: Walther,T.; Wessel,N.; Kang,N.; Sander,A.; Tschöpe,C.; Malberg,H.; Bader,M.; Voss,A.
Heart rate variability is a relevant predictor of cardiovascular risk in humans. A significant genetic influence on heart rate
variability is suggested, although the genes involved are ill-defined. The Mas-protooncogene encodes a G-protein-coupled
receptor with seven transmembrane domains highly expressed in testis and brain. Since this receptor is supposed to interact with
the signaling of angiotensin II, which is an important regulator of cardiovascular homeostasis, heart rate and blood pressure were
analyzed in Mas-deficient mice. Using a femoral catheter the blood pressure of mice was measured for a period of 30 min and 250
data values per second were recorded. The mean values and range of heart rate and blood pressure were then calculated. Neither...
Tipo: Journal article
Palavras-chave: Blood pressure variability; Heart rate variability; Baroreflex sensitivity; Mas protooncogene.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000100001
Reducing milking cow stress by increasing the number of times inexperienced milkers milk
Provedor de dados: 19
Autores: 古村, 圭子; 葉山, 桂子; 鈴木, 耕太朗; FURUMURA, Keiko; HAYAMA, Keiko; SUZUKI, Kotaro.
初めて搾乳を行う 5人の搾乳未経験者が搾乳した日乳量は、搾乳経験者が搾乳した日乳量に比 べて減少することが示
された。それは搾乳未経験者が搾乳牛に緊張やストレスを与えたためと考 えられた。また搾乳未経験者は搾乳準備
時間が手間取るため長くなり、そのことが残乳を増やし たと思われ、日乳量の減少につながったと考えられた。ミ
ルカーをつける直前の搾乳準備時の搾 乳牛心拍数を、搾乳前安静時と比べた心拍変動率で表した。搾乳未経験者の
搾乳経験回数の増加 に伴って、心拍変動率に５頭全頭における一定の変化パターンは見られなかったが、搾乳準備
時 間の短い牛では、心拍変動率が有意に減少した（P<0.05）。同じ搾乳施設では未経験者の搾乳回数 が増加するに
つれて、搾乳準備時間は減少し、その時間帯の乳牛の肢上げと蹴り行動も減少した。 搾乳施設が代わるとまた未経
験者の搾乳準備時間が長引く傾向がみられた。以上から、搾乳未経 験者は搾乳牛にストレスや緊張を与えて肢上げ
や蹴り行動が増加し、心拍変動率が有意に増加し （P<0.05）、その結果日乳量の減少をもたらした。しかし累積搾
乳回数の増加に従い、肢上げや蹴 り行動が減少し搾乳準備時間も短くなり、心拍変動率も下がることを示した。
Palavras-chave: Stress; Milking experience; Heart rate variability; Daily milk yield; Milk cow; Behavior.
Ano: 2014
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3995