Acceleration Change Index for Heart Rate Variability Analysis
Acceleration changes index (ACI) is a fast and robust marker for analysis of heart rate variability (HRV) dynamics, the index characterizes the sign of difference of time series and theoretical study relates it to autocorrelation function of the time series. HRV time series contains information on the neural modulation of cardiovascular system by autonomic nervous system. Considerable attention has been focused on the potential health benefits of a variety of meditative, relaxation techniques and their possible effects on autonomic nervous system. We Applied ACI to analyze heart rate time series from two groups of healthy young adults before and during two well known forms of mediation. We also explored ACI for RR-interval time series of young and elderly subjects watching fantasia movie and healthy young adults during exercise. It was observed that ACI was almost constant for mediation state and varied for the pre-mediation state. ACI increased during the exercise and was lower for young subjects as compared with the elderly subjects.