Heart Rate Variability Assessment Using Doppler Radar with Linear Demodulation

Heart rate variability (HRV) describes the time variation in beat-to-beat interval, and reflects the manner in which the cardiovascular regulatory system responds to demands, stress, and illness. A particular advantage of Doppler radar for HRV monitoring is the ability to detect and monitor heart and respiration signals simultaneously, and thus provide independent measures of HRV, and respiration-related fluctuations. High accuracy in obtaining HRV parameters using Doppler radar is achieved using linear demodulation method, including SDNN of about 10 ms, and mean beat to beat interval accuracy of close to 1 ms. In addition, respiration signals were obtained simultaneously with the heart signals, clearly showing a correlation between respiration cycles and heart rate variability.