FBG-Based Mattress for Heart Rate Monitoring in Different Breathing Conditions

In recent years, extensive investigations have been geared toward finding unobtrusive solutions for monitoring cardiorespiratory activity as an alternative to traditional clinical methods. Among others, the ones based on fiber Bragg grating (FBG) sensors reveal remarkable promise for monitoring respiratory rate (RR) and heart rate (HR). The present study investigates the performance of a mattress based on a 13-FBG array for HR continuous estimation. First, a metrological characterization was performed to assess system characteristics under frequencies simulating typical HR values [i.e., 60, 90, and 120 beats per minute (bpm)]. Then, the proposed device was tested on eight healthy volunteers (both males and females) in the presence of different breathing stages (i.e., quiet breathing and tachypnea) while mimicking common sleeping postures (i.e., supine, left side, and prone). The assessment of HR measurements under different breathing regimes and postures has rarely been addressed in FBG-based technologies. The achieved results suggest that the proposed mattress has promising capability in reliably estimating HR values. These results together with the ones obtained in terms of RR monitoring in a recent study reveal the high potential for monitoring cardiorespiratory activity.