Search Results
Results 451 - 500 of 802
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Hautala Arto J - - 2003
Individual responses to aerobic training vary from almost none to a 40% increase in aerobic fitness in sedentary subjects. The reasons for these differences in the training response are not well known. We hypothesized that baseline cardiovascular autonomic function may influence the training response. The study population included sedentary male ...
Beckers F - - 2003
During parabolic flight short periods of microgravity and hypergravity are created. These changes influence cardiovascular function differently according to posture. During the 29th parabolic flight campaign of the European Space Agency (ESA), the electrocardiogram (ECG) was recorded continuously in seven healthy volunteers in two positions (standing and supine). Five different ...
Lee C Matthew - - 2003
PURPOSE: To examine the influence of 2 wk (eight sessions) of endurance training on cardiac autonomic modulation, as measured by heart rate variability (HRV). METHODS: Twenty-four males (mean age: 23.1 yr) were randomized to an exercise (EX; N = 12) or control group (CT; N = 12). EX trained for ...
Leicht Anthony S - - 2003
The purpose of this study was to examine the influence of age and moderate-intensity exercise training on heart rate variability (HRV), and to elucidate further the mechanism of training-induced bradycardia and cardioprotection. Electrocardiograms were recorded from 12 young (18-24 yrs) and 12 mature (29-43 yrs) individuals during supine rest and ...
Woodman Christopher R - - 2003
We tested the hypothesis that exercise training (Ex) attenuates the effects of hyperlipidemia on endothelial function by enhancing NO-mediated vasorelaxation in porcine brachial (Br) arteries. Adult female pigs were fed a normal-fat (NF) or high-fat (HF) diet for 20 wk. Four weeks after initiation of the diet, pigs underwent Ex ...
Jáuregui-Renaud Kathrine K Unidad de Investigación Medica, Hospital General, Centro Medico Nacional La Raza, Instituto Mexicano del Seguro Social, Mexico City, Mexico. - - 2003
Experimental work indicates that the vestibular system participates in autonomic reflexes during body movement and postural changes. However, there are no studies of cardiovascular reflexes during vertigo due to human acute vestibular lesions. We assessed the response to active change of posture and hand immersion in cold water in seven ...
Dela Flemming - - 2003
BACKGROUND: We studied the role of the central nervous system, neural feedback from contracting skeletal muscles, and sympathetic activity to the heart in the control of heart rate and blood pressure during 2 levels of dynamic exercise. METHODS AND RESULTS: Spinal cord-injured individuals (SCI) with (paraplegia, n=4) or without (tetraplegia, ...
Straube Thomas - - 2003
Long-term potentiation (LTP) in the hippocampus of awake animals is known to be reversed by long trains of low-frequency stimulation (LFS). Here we show that a persistent LTP reversal, i.e. depotentiation (DP), can be induced in the dentate gyrus of freely moving rats by brief 7 Hz stimulations (three trains ...
Balt Jippe C - - 2003
Both in human and in experimental heart failure (HF), the renin-angiotensin system and the sympathetic nervous system are activated. In a previous study a facilitatory action of angiotensin II (Ang II) was shown in the rabbit mesenteric artery, which was mediated via prejunctionally located Ang II type 1 (AT ) ...
Ueno Linda Massako - - 2003
Reductions in tonic vagal controls of the heart and depressed baroreflex sensitivity (BRS) have been associated with a postural fall in blood pressure (BP) and the incidence of cardiac events among older people. We examined the hypothesis that BP regulation during orthostatic challenge as well as heart rate variability (HRV) ...
Yamamoto Yoshiharu - - 2003
The use of symptoms generated by head up tilt (HUT) is not a useful tool in identifying chronic fatigue syndrome (CFS). We investigated whether heart rate variability (HRV) assessed early during HUT might be useful. A sample of 46 female subjects (24 with CFS and 22 sedentary, age-matched healthy controls; ...
Facchini M - - 2003
The autonomic control of the heart is abnormal in obese subjects due to a prevalence of sympathetic over parasympathetic limb of the autonomic balance. We evaluated the effects of a short-term (3 weeks) integrated body weight reduction program (consisting of energy restricted diet and high-intensity exercise training) on heart rate ...
Zenon Gawor - - 2003
Heart rate variability is a widely used method to evaluate vagal and sympathetic influences on the heart. The purpose of this study was to assess the relationship of autonomic nervous system components' interaction in supersonic fighter pilots by means of a sinus rhythm variability analysis. The following frequency domain parameters ...
Migeotte P-F - - 2003
We studied heart rate (HR), heart rate variability (HRV), and respiratory sinus arrhythmia (RSA) in four male subjects before, during, and after 16 days of spaceflight. The electrocardiogram and respiration were recorded during two periods of 4 min controlled breathing at 7.5 and 15 breaths/min in standing and supine postures ...
Forte Roberta - - 2003
Twenty healthy women aged between 65 and 74 years, trained three times a week, for 16 weeks, on a cycle ergometer, to determine the effects of dynamic resistance training on heart rate variability (HRV). Subjects were allocated to two training groups, high (HI, n=10) and low (LO, n=10) intensity. The ...
Udupa Kaviraja - - 2003
Systolic time intervals (STI) are non-invasive and sensitive tests for measuring the ventricular performance. It has been reported that practice of pranayam modulates cardiac autonomic status and improves cardio-respiratory functions. Keeping this in view, the present study was designed to determine whether pranayam training has any effect on ventricular performance ...
Honzíková N - - 2003
The correlation between baroreflex sensitivity (BRS) and the spectrum component at a frequency of 0.1 Hz of pulse intervals (PI) and systolic blood pressure (SBP) was studied. SBP and PI of 51 subjects were recorded beat-to-beat at rest (3 min), during exercise (0.5 W/kg of body weight, 9 min), and ...
Miller Michael - - 2003
Superimposed electrical stimulation techniques can be used to detect central activation failure (CAF), that is, incomplete central nervous system recruitment or suboptimal activation of motor units. The purpose of this study was to evaluate the effects of two stimulation parameters on perceived discomfort and torque increment size and variability. Discomfort ...
Barclay Linda - - 2003
In this paper I argue that the genetic manipulation of sexual orientation at the embryo stage could have a detrimental effect on the subsequent person's later capacity for autonomous agency. By focussing on an example of sexist oppression I show that the norms and expectations expressed with this type of ...
Carter James B - - 2003
Long-term endurance training significantly influences how the autonomic nervous system controls heart function. Endurance training increases parasympathetic activity and decreases sympathetic activity in the human heart at rest. These two training-induced autonomic effects, coupled with a possible reduction in intrinsic heart rate, decrease resting heart rate. Long-term endurance training also ...
Katoh Kansei - - 2003
BACKGROUND: Activation of glucagon receptors of the smooth muscle membrane suppresses gastric peristalsis. We evaluated autonomic nervous activity by two methods, electrogastrography (EGG) and analysis of heart rate variability, to compare the inhibiting effects of glucagon and scopolamine butylbromide on gastric peristalsis. METHODS: Heart rate variability, EGG, and blood catecholamine ...
Aubert André E - - 2003
This review examines the influence on heart rate variability (HRV) indices in athletes from training status, different types of exercise training, sex and ageing, presented from both cross-sectional and longitudinal studies. The predictability of HRV in over-training, athletic condition and athletic performance is also included. Finally, some recommendations concerning the ...
Souza-Rabbo Maristela P - - 2003
The present study investigated the influence of different frequencies of moderate exercise (13 weeks of treadmill running at 60% of maximal oxygen consumption) on oxidative stress in the heart and liver in rats. Oxidative stress was evaluated by chemiluminescence and lipid peroxidation (LPO) through thiobarbituric acid reactive substances. Activities of ...
Fries Roland - - 2002
BACKGROUND: It is generally supposed that diurnal fluctuations of heart rate variability (HRV) are associated with diurnal variability of occurrence of sudden cardiac death, usually caused by tachyarrhythmias. To date, however, there have been no data comparing circadian rhythms of HRV and circadian variability of malignant ventricular tachyarrhythmias in the ...
Roussel M - - 2003
Onset of intracellular acidosis during muscular exercise has been generally attributed to activation or hyperactivation of nonoxidative ATP production but has not been analyzed quantitatively in terms of H(+) balance, i.e., production and removal mechanisms. To address this issue, we have analyzed the relation of intracellular acidosis to H(+) balance ...
Pichot Vincent - - 2002
PURPOSE: Looking for practical and reliable markers of fatigue is of particular interest in elite sports. One possible marker might be the autonomic nervous system activity, known to be well affected by physical exercise and that can be easily assessed by heart rate variability. METHODS: We designed a laboratory study ...
Sica Anthony L - - 2002
The hypothesis that hypercapnia-induced differences in heart rate variability (HRV) would emerge during early maturation was tested using a developing porcine model. Piglets were randomly assigned to either exposed (10% CO2 for 1 h) or control (100% O2) conditions, and then to one of three study groups: (a) 5-8 days ...
Herbert Rowan W L - - 2002
The aim of this study was to examine the influence of 20 min of hard exercise (HR>160 beats min(-1)) on the efficacy of the cardiac parasympathetic nervous control of heart rate in humans (20-31 years; of either sex). This intensity of exercise was chosen to produce strong activation of the ...
Ueno Linda Massako - - 2002
BACKGROUND: Aging associated changes in sympatho-vagal activities have been widely studied. However, little is known about the association between cardiorespiratory fitness level and cardiac autonomic nervous activities in conjunction with baroreflex sensitivity in healthy older men. METHODS: We performed an incremental submaximal exercise test in 24 healthy, older men aged ...
Schneider Suzanne M - - 2002
PURPOSE: Supine, moderate exercise is ineffective in maintaining orthostatic tolerance after bed rest (BR). Our purpose was to test the hypothesis that adding an orthostatic stress during exercise would maintain orthostatic function after BR. METHODS: Seven healthy men completed duplicate 15-d 6 degrees head-down tilt BR using a crossover design. ...
Elstad Maja - - 2002
We have tested whether the cardiovascular changes at the onset of exercise could be simulated only by an increase in the baroreflex set point and locally induced vasodilatation in the exercising muscles. The mathematical model consists of a heart, a linear elastic arterial reservoir and two parallel resistive vascular beds. ...
Javorka M - - 2002
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 ...
Bettermann Henrik - - 2002
Our objective was to study the effects of guided rhythmic speech with poetry, referred to as anthroposophical therapeutic speech (ATS), on binary differential heart rate dynamics (also called musical heart rate rhythmicity or HRR) as well as on classical spectral parameters during the 15 min after a speech exercise had ...
Iellamo Ferdinando - - 2002
BACKGROUND: Benefits of moderate endurance training include increases in parasympathetic activity and baroreflex sensitivity (BRS) and a relative decrease in sympathetic tone. However, the effect of very intensive training load on neural cardiovascular regulation is not known. We tested the hypothesis that strenuous endurance training, like in high-performance athletes, would ...
Cooke William H - - 2002
PURPOSE: We tested the hypothesis that a strictly-controlled program of aerobic conditioning would increase vagal and decrease sympathetic responses to Valsalva straining. METHODS: Eleven young men performed a maximal aerobic capacity test, controlled frequency breathing (0.25 Hz), and three Valsalva maneuvers before and after 4 wk of exercise training on ...
Pietilä Mikko - - 2002
Abnormalities of autonomic nervous function are associated with a poor prognosis of patients with chronic heart failure (CHF). We studied the effects of a 6-mo exercise training program on Q-T interval dispersion, heart rate and blood pressure variability, baroreflex sensitivity, myocardial blood flow (MBF), and presynaptic sympathetic innervation in 13 ...
Sakuragi Sokichi - - 2002
We investigated the effects of laughing and weeping induced by watching comedy and tragedy videos on mood and autonomic nervous function. Ten healthy female subjects volunteered for the experiment. Chest electrocardiogram and respiration curve were recorded before, after, and during watching a comedy or a tragedy video. We also asked ...
Kawamoto M - - 2002
BACKGROUND: Although one lung ventilation (OLV) is commonly used, little is known about the modulation of the autonomic nervous system with OLV while under general anesthesia. As the frequency domain and time domain analyses are powerful analytic tools, we investigated their modulation during OLV. METHODS: Patients undergoing thoracic surgery were ...
James D V B - - 2002
We investigated the effect of exercise on heart rate variability by analysing the heart rate power spectrum prior to, and 1 and 72 h following, an interval training session. Subjects initially performed a graded test to exhaustion to determine maximal oxygen uptake (VO(2) max) and the running speed at which ...
Perini Renza - - 2002
PURPOSE: The effects of an intense 8-wk aerobic training program on cardiovascular responses at rest and during exercise, including heart rate variability (HRV) as an expression of autonomic modulation, were evaluated in subjects over 70 yr (mean: 73.9 +/- 3.5 yr). METHODS: Before and after training in 7 men and ...
Negoes Radu - - 2002
27 consecutive insulin-dependent diabetic patients (pts), under 50 years, with blood glucose controlled within normal limits and no significant or multiple cardiovascular/neurological complications in the lights of clinical tests, went through a protocol as follows: laiddown at relaxed rest for 10 min, then stood-up quietly for 7 min, and finally ...
Malfatto Gabriella - - 2002
A gradual worsening of autonomic control of cardiovascular function accompanies the progression of heart failure. Exercise training modulates autonomic balance, and may affect the prognosis of the disease. The sympathovagal balance was studied after 3 months of low-intensity rehabilitation compared with conventional therapy in 45 patients with heart failure (52% ...
Takenaka Katsu - - 2002
To test whether acute volume expansion can normalize orthostatic intolerance and autonomic tone after prolonged bed rest (BR), 23 men were subjected to 20 days BR. Left ventricular (LV) echocardiography was performed during the lower body negative pressure (LBNP) test before and after BR with and without preceding rapid infusion ...
Myslivecek Paula R - - 2002
The purpose of this study was to determine whether moderate exercise training affects heart rate variability (HRV) and spontaneous baroreflex (SBR) function in healthy middle-aged women. Thirty-two sedentary women aged 40-59 yr were divided into four groups depending on reproductive state (premenopausal, PrM or postmenopausal, PoM, and training group (exercise ...
Yeragani Vikram Kumar - - 2002
In this study, we reanalyzed our previous heart rate time series data on the effects of intravenous sodium lactate (n=9) and intravenous isoproterenol (n=11) using non-linear techniques. Our prior findings of significantly higher baseline non-linear scores (NL: S(netGS)) and significantly lower largest Lyapunov exponents in supine posture in patients with ...
Hjelland I E - - 2002
BACKGROUND/AIMS: Patients with functional dyspepsia often have meal-induced dyspeptic symptoms and low vagal tone. We examined whether these variables are related in healthy subjects. METHODOLOGY: In 40 healthy subjects vagal tone and abdominal symptoms were recorded before and after a 500-ml soup meal ingested in 1 and 4 min on ...
Väänänen Janne - - 2002
A group of 15 elderly men and 14 young male students of physical education made twice a series of Taichiquan (TCQ) practices. Their electrocardiograms were recorded on tape-recorder and heart rates and heart rate variability (HRV) were calculated from digitized data. Here we report the results of recordings in supine ...
Kaufman Marc P - - 2002
Stimulation of group III and IV muscle afferents has been shown to have important reflex effects on both the somatic and autonomic nervous systems. These include an inhibitory effect on alpha motoneurones, an excitatory effect on gamma motoneurones and an excitatory effect on the sympathetic nervous system. The purpose of ...
De Vito G - - 2002
The profound reduction in heart rate variability (HRV) that occurs during exercise is thought to be, at least in part, the result of sympathetic nervous system activation. Moxonidine is a centrally acting anti-sympathetic drug, which suppresses sympathetic nervous system outflow by stimulation of central imidazoline receptors located in the rostral ...
Akita Megumi - - 2002
We established characteristics of power spectral analysis of heart rate variability, and assessed the diurnal variations of autonomic nervous function in guinea pigs. For this purpose, an electrocardiogram (ECG) was recorded for 24 hr from conscious and unrestrained guinea pigs using a telemetry system. There were two major spectral components, ...
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