Heart rate variability (HRV) is traditionally derived from RR interval time series of electrocardiography (ECG). Photoplethysmography (PPG) also reflects the cardiac rhythm since the mechanical activity of the heart is coupled to its electrical activity. Thus, theoretically, PPG can be used for determining the interval between successive heartbeats and heart rate variability. However, the PPG w...

The results of studies into the prognostic value of heart rate variability (HRV) for cardiac and all0022-0736/$ – see fro doi:10.1016/j.jelectroc 4 Corresponding E-mail address: j. cause mortality in the general population are briefly reviewed, and the effect of various recording durations of the electrocardiogram (ECG) on HRV parameters is assessed. Heart rate variability parameters offer prog...

Biological organisms have intrinsic control systems that act in response to internal and external stimuli maintaining homeostasis. Human heart rate is not regular and varies in time and such variability, also known as heart rate variability (HRV), is not random. HRV depends upon organism's physiologic and/or pathologic state. Physicians are always interested in predicting patient's risk of deve...

Heart rate variability (HRV) measures have been used to assess autonomic cardiac regulation. The standard lengths used in HRV analyses are 5 minutes and 24 hours. In this paper we investigated the accuracy of three HRV measures for ultra-short record length, 10 seconds, which is the length of standard electrocardiograms. The measures chosen were: Standard Deviation Normal– Normal (SDNN), Root M...

BACKGROUND The study of the correlation of menopausal symptoms with heart rate variability (HRV) has not been adequate. The aim of this study was to investigate the relationship between postmenopausal symptoms measured by the menopause rating scale (MRS) and HRV. METHODS We assessed postmenopausal symptoms (using MRS) with age, BMI, educational status, occupation, marital status, alcohol and ...

background and objective: obstructive sleep apnea syndrome (osas) is a prevalent disease in adults. limited evidence regarding the effect of severity of sleep apnea and depression on heart rate variability (hrv) indices exists. hence, we decided to focus on the association between hrv and severity of osas based on depression score. materials and methods: a total of 193 patients with confirmed o...

Background. A biofeedback program receives attention as an intervention program for athletes to regulate their psychological state. Objectives. The purpose was to apply for a heart rate variability (HRV) biofeedback training program and validate its effectiveness for racket sports players. Methods. The participants were eight elite sport athletes (three men and five women): five squash players...

Aims: The aim of this study was to evaluate the effect of stress inoculation on laboratory markers such as heart rate variability and salivary cortisol and clinical outcomes (anxiety, stress and depression) of patients undergoing coronary artery bypass graft surgery.  Methods & Materials: The research is a semi experimental study with the pre, post-test and experimental and control groups. The...

BACKGROUND It is unclear from prior reports whether the relationships between self-ratings of anxiety or emotional stress and parasympathetic nervous system components of heart rate variability are independent of personality and cardiorespiratory fitness. We examined those relationships in a clinical setting prior to a standardized exercise test. METHODS AND RESULTS Heart rate variability (HR...