Heart rate variability (HRV) is a noninvasive indicator of autonomic control. This study examines HRV changes across a normal menstrual cycle and proposes a novel piecewise function controlling for the effects of breathing on HRV spectral parameters. A resting ECG was collected from 13 women at five points in their menstrual cycle. Both heart rate and breathing rate increased across the cycle (...

OBJECTIVE Based on prior research showing inverse associations between heart rate and life expectancy, we tested the hypothesis that adults with higher resting heart rate in middle age were more likely to have diagnosed diabetes or to experience diabetes mortality in older age (>65 years). RESEARCH DESIGN AND METHODS Resting heart rate was measured at baseline (1967-1973) in the Chicago Heart...

BACKGROUND We sought to evaluate the prognostic significance of premature ventricular contractions (PVCs) on a routine electrocardiogram (ECG) and to evaluate the relationship between heart rate and PVCs. METHODS Computerized 12-lead ECGs of 45,402 veterans were analyzed. Vital status was available through the California Health Department Service. RESULTS There were 1731 patients with PVCs ...

background: despite the widespread use of respiratory protection equipment in different jobs, the effects of these devices on people’s physiological responses are not well recognized as yet. therefore, the aim of this study is to evaluate the effect of the air purifying respiratory protection equipment on the heart rate. methods: this experimental study was performed in a climate chamber under ...

BACKGROUND Increased resting heart rate (RHR) may be associated with increased cardiovascular morbidity. Our aim was to explore the possibility that increased RHR is associated with the prevalence of the metabolic syndrome (MetS) in a sample of apparently healthy individuals and those with cardiovascular risk factors. METHODS We performed a cross-sectional analysis in a large sample of appare...

Twelve healthy volunteers were given one week's oral treatment with each of 300 mg nizatidine, 40 mg famotidine, and placebo once daily in a randomised, placebo controlled, double blind study. Three hours after administration, nizatidine led to a significant reduction in the mean (SD) resting heart rate compared with placebo (63.6 (6.4) beats/minute on placebo to 55.9 (7.2) beats/minute on niza...

introduction: the prevalence of chronic diseases increases with age. increased production of reactive oxygen species (ros) involves in the pathogenesis of cardiovascular diseases such as coronary atherosclerosis, hypertension, diabetic vascular complications, and heart failure. the present study aimed to explore the effects of resistance training on plasma hydrogen peroxide level of ageing wome...

Introduction: Studies have reported hyperlipidemia and its complications, such as diabetes, along with aging. Omentin-1, on the other hand, is a protein that is secreted in visceral adipose tissue and can increase insulin sensitivity. This study aimed at evaluating the effect of aerobic exercise on resting levels of omentin-1, C-reactive protein, and some metabolic parameters in middle-aged men...

Heart rate during overnight rest and while diving were recorded from five emperor penguins with a microprocessor-controlled submersible recorder. Heart rate, cardiac output and stroke volume were also measured in two resting emperor penguins using standard electrocardiography and thermodilution measurements. Swim velocities from eight birds were obtained with the submersible recorder. The resti...