Spectrum Analysis of Heart Rate Variability (HRV)

Abstract: Heart Rate Variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. High frequency (HF) HRV signals (0.12-0.4 Hz), especially, has been linked to parasympathetic nervous system (PSNS) activity. Activity in this range is associated with the respiratory sinus arrhythmia (RSA). In this thesis, we are interested in the differences between the power of HF-HRV in lying down position and standing up position, using analysis the HRV signal in frequency domain. Four non-parametric window spectrum methods are introduced for estimating the Power Spectra Density (PSD). Then the power of HRV is calculated using a traditional bandwidth [0.12-0.4] as well as a designed new bandwidth [ f0 ± B ], where f0 is the corresponding peak frequency from RSA spectrum. From combing different methods with different bandwidths; the resulting estimated power are compared in two different positions in many ways. In the end, the hypothesis tests are constructed to check if there exists a significant difference in the mean and variance for different methods with for different bandwidths. Moreover, the robust methods are applied to analysis the HRV signal during some Yoga breathing exercises. All data in used are collected from a pre-designed experiment in February that held in IKDC in Lund.