Background: Recent studies have claimed a positive effect of physical activity and body composition on vagal tone. In pediatric populations, there is a pronounced decrease in heart rate with age. While this decrease is often interpreted as an age-related increase in vagal tone, there is some evidence that it may be related to a decrease in intrinsic heart rate. This factor has not been taken in...

This study tests the hypothesis that high levels of high-frequency heart rate variability (HF-HRV) predisposes individuals to affiliate with new groups. Resting cardiac physiological recordings were taken before and after experimental sessions to measure trait high-frequency heart rate variability as an index of dispositional autonomic influence on heart rate. Following an experimental manipula...

OBJECTIVE We aimed to study short-term heart rate variability (HRV) in 113 apparently healthy children permanent residents of moderate altitudes, the effects of gender and altitude. METHODS Children were assigned into 3 groups according with altitude of residence: Group 1--1650 m/a/s/l (n=38), Group 2--1740 m/a/s/l (n=36) and Group 3--2030 m/a/s/l (n=39). All children underwent short-term ele...

Heart rate variability (HRV) reflects the healthiness of autonomic nervous system, which is associated with exercise capacity. We therefore investigated whether HRV could predict the exercise capacity in the adults with cardiac syndrome X (CSX). A total of 238 subjects (57±12 years, 67.8% men), who were diagnosed as CSX by the positive exercise stress test and nearly normal coronary angiogram w...

BACKGROUND Reduced measures of heart rate variability (HRV) have been shown to be related with prognosis in heart failure. Chronic administration of trimetazidine in addition to the conventional therapy has been shown to improve functional class and left ventricular functions of heart failure patients. OBJECTIVE To assess the effects of trimetazidine on HRV in optimally treated patients with ...

background: central obesity and hyperinsulinaemia of polycystic ovary syndrome (pcos) are associated with chronic sympathetic over activity. objective: to evaluate the autonomic functions and to indicate the superiority, if any, for those functions in the diagnosis of sympathetic over activity in pcos women. materials and methods: sixty-four pcos patients and 40 women served as the control grou...

BACKGROUND Several studies have demonstrated the importance of the autonomic nervous system through sympathetic and parasympathetic components in the management of the interaction between different parts of the body. These studies have applied linear and nonlinear techniques (Chaos Theory) for assessment in different situations, illnesses and age groups, using the heart rate variability (HRV). ...

BACKGROUND Measurements of heart rate variability (HRV) are increasingly used as markers of cardiac autonomic activity. AIM To examine circadian variation in heart rate and HRV in children. SUBJECTS A total of 57 healthy infants and children, aged 2 months to 15 years, underwent ambulatory 24 hour Holter recording. Monitoring was also performed on five teenagers with diabetes mellitus and s...

Heart rate variability (HRV) is a non-invasive maker of cardiac autonomic modulation utilised in many hundreds of scientific studies each year. The reliability of heart rate variability has been frequently investigated yet remains poorly quantified. Assessing the reliability of a measure that assesses dynamic physiological processes and shows large between and within-subject variation is a comp...