Search results for "HEART RATE"

Heart Rate Is a Better Predictor of Cardiorespiratory Fitness Than Heart Rate Variability in Overweight/Obese Children: The ActiveBrains Project

2019

The authors would like to thank all the participants who volunteered for this investigation. This work is part of a Ph.D. thesis conducted in the Biomedicine Doctoral Studies of the University of Granada, Spain.

Causal linear parametric model for baroreflex gain assessment in patients with recent myocardial infarction

2001

Spectral and cross-spectral analysis of R-R interval and systolic arterial pressure (SAP) spontaneous fluctuations have been proposed for noninvasive evaluation of baroreflex sensitivity (BRS). However, results are not in good agreement with clinical measurements. In this study, a bivariate parametric autoregressive model with exogenous input (ARXAR model), able to divide the R-R variability into SAP-related and -unrelated parts, was used to quantify the gain (αARXAR) of the baroreflex regulatory mechanism. For performance assessing, two traditional noninvasive methods based on frequency domain analysis [spectral, baroreflex gain by autogressive model (αAR); cross-spectral, baroreflex gain…

P330Modifications of short-term heart rate varibility and intrinsic pacemaker variability in an experimental model of metabolic syndrome

2018

60-Hour Sleep Deprivation Affects Submaximal but Not Maximal Physical Performance

2018

The effect of 60-h sleep deprivation (SD) on physical performance and motor control was studied. Twenty cadets were measured for aerobic performance (VO2) before and immediately after the SD period. Maximal strength and EMG of the knee extensor muscles were measured before and after 60 h of SD. Balance, reaction times and motor control were assessed every evening and morning during the SD period. Main effects were observed for heart rate (p = 0.002, partial eta squared: 0.669), VO2 (p = 0.004, partial eta squared: 0.621), ventilation (p = 0.016, partial eta squared: 0.049), and lactate concentration (p = 0.022, partial eta squared: 0.501), whereas RER remained unaltered (p = 0.213, partial …

Influence of Vascular Load on Plasma Endothelin-1, Cytokines and Catecholamine Levels in Essential Hypertensives

1998

In vitro studies demonstrated a relationship between ET-1 and basic Fibroblast Growth Factor (bFGF), and of bFGF with Platelet Derived Growth Factor (PDGF). The present study was carried out to investigate in vivo the behaviour after vascular stress of circulating ET-1, bFGF and PDGF, and catecholamines, and their relationship. In 12 healthy normotensives (NTs) and 15 essential hypertensives (Ehs) venous blood samples to determine circulating ET-1, bFGF and PDGF, and catecholamine (EPI and NE) levels were drawn before and at the third minute of a handgrip test. Blood pressures (BP) and heart rate were automatically recorded before starting, and at 1, 2, and 3 minutes during the test. The NT…

Effects of prandial glycemic changes on objective fetal heart rate parameters

2000

Background. There is confusion in the literature about the potential effect of maternal glucose levels on the fetal heart rate (FHR) cardiotocographic interpretation.Methods. Study design: prospective clinical descriptive study. Subjects: 21 pregnant women with diabetes mellitus, 23 women with gestational diabetes and 18 healthy non-diabetic pregnant volunteers (control group). Treatment: maternal capillary glucose measurement and objective FHR analysis (Oxford System 8002) pre- and 1 h post-meal. Statistical analysis: descriptive statistics, Student t-tests and Pearson correlation studies.Results. Maternal capillary glucose levels ranged between 2.7–10.5 mmol/l pre-meal and 4.2–14.8 mmol/l…

Intrinsic changes on automatism, conduction, and refractoriness by exercise in isolated rabbit heart.

2001

We have studied the intrinsic modifications on myocardial automatism, conduction, and refractoriness produced by chronic exercise. Experiments were performed on isolated rabbit hearts. Trained animals were submitted to exercise on a treadmill. The parameters investigated were 1) R-R interval, noncorrected and corrected sinus node recovery time (SNRT) as automatism index; 2) sinoatrial conduction time; 3) Wenckebach cycle length (WCL) and retrograde WCL, as atrioventricular (A-V) and ventriculoatrial conduction index; and 4) effective and functional refractory periods of left ventricle, A-V node, and ventriculoatrial retrograde conduction system. Measurements were also performed on coronary…

Competitive active video games: Physiological and psychological responses in children and adolescents

2015

Recent strategies to reduce sedentary behaviour in children include replacing sedentary screen time for active video games. Active video game studies have focused principally on the metabolic consumption of a single player, with physiological and psychological responses of opponent-based multiplayer games to be further evaluated.To determine whether adding a competitive component to playing active video games impacts physiological and psychological responses in players.Sixty-two healthy Caucasian children and adolescents, nine to 14 years years of age, completed three conditions (8 min each) in random order: treadmill walking, and single and opponent-based Kinect active video games. Affect,…

Impact of Nonstationarities on Short Heart Rate Variability Recordings During Obstructive Sleep Apnea

2017

Obstructive sleep apnea (OSA) is a sleep disorder characterized by breathing pauses due to collapse of the upper airways. During OSA the autonomic modulation, as noninvasively assessed through heart period (HP) variability, is altered in a time-varying way even though time-varying properties of HP fluctuations are often disregarded by HP variability studies. We performed a time domain analysis computed over very short epochs corresponding to the sole OSA events explicitly accounting for HP variability nonstationarities. Length-matched epochs were extracted during OSA and quiet sleep (SLEEP) in 13 subjects suffering from OSA (11 males, age 55±11, apnea-hypopnea index 44±19). Mean HP, varianc…

Effects of vigorous late-night exercise on sleep quality and cardiac autonomic activity

2011

Sleep is the most important period for recovery from daily load. Regular physical activity enhances overall sleep quality, but the effects of acute exercise on sleep are not well defined. In sleep hygiene recommendations, intensive exercising is not suggested within the last 3 h before bed time, but this recommendation has not been adequately tested experimentally. Therefore, the effects of vigorous late-night exercise on sleep were examined by measuring polysomnographic, actigraphic and subjective sleep quality, as well as cardiac autonomic activity. Eleven (seven men, four women) physically fit young adults (VO(2max) 54±8 mL·kg(-1)·min(-1) , age 26±3 years) were monitored in a sleep labor…