Heart Rate Variability And Cognitive And Mind Body...

Heart rate variability is defined as the variation in the interval between normal heart beats and provides an important non-invasive assessment of cardiac autonomic control. It is postulated to be the effect of the interplay between the sympathetic and the parasympathetic components of the autonomic nervous system. The SA node receives different inputs from the SNS, PSNS and the humoral factors which cause the beat to beat variation in the heart rate. Heart rate variability is thus an important indicator of autonomic tonal variations. It has also been postulated to be the mediator of the effects of cognitive and mind-body therapies on cardiovascular conditions. The ANS is the primary regulator of heart rate in the human†¦show more content†¦These factors are reflected in spectral analysis of HRV, identifying 3 major components : †¢ High Frequency Peak (HF 0.1 Hz): corresponding to respiratory sinus arrhythmia. Vagal moderation causes the decrease in the heart rate during expiration and increase during inspiration. The variation usually tracks the respiratory rate across a range of frequencies and is related to parasympathetic NS activity. †¢ Low Frequency Peak (LF -0.04-0.09 Hz): This is associated with Traube-Hering-Mayer waves of arterial pressure. LF variation is influenced by SNS or a combination of SNS and PSNS. †¢ Very-low Frequency Component (VLF 0.04 Hz): Related to expression of peripheral vasomotor regulation. Measurement of Heart rate variability: Measurements of beat to beat variability are done under controlled resting conditions and involve measuring the RR interval from an EKG, measuring of beats using blood pressure or the pulse wave signal derived from a photoplethysmograph (PPG). Variations in RR variability are measured by different methods which are: 1. Time domain Measures 2. Frequency Domain Measures 3. Non-linear/Complexity- based Measures The measures most often available from commercial software include: †¢ Standard deviation of NN (normal to normal RR) intervals over a 24-hour period (SDNN) or over a brief (usually five minute) measuring period. †¢ Standard deviation of the average NN intervals for the 288