Assessment of an innovative smart face mask for the estimation of respiratory rate in static and dynamic conditions

Many occupational settings need the use of face masks, and the current COVID-19 pandemic has led to an unprecedented demand for this personal protective device. In this context, smart devices built inside the face mask that can track physiological data can be helpful for several reasons. Respiratory rate (RR) is one of many important physiological indicators because of its sensitivity to different physiological and physical stress situations. In this paper, two thermistors were embedded within a commercial face mask to monitor RR in static (standing and sitting positions) and dynamic (during walking) conditions. The feasibility assessment of this smart face mask (SFM) for estimating RR has been performed by comparing the results found on 8 healthy volunteers with a reference system. The SFM showed promising results in two different respiratory regimes (i.e., quiet breathing - QB, tachypnea - T). While sitting, the mean absolute error (MAE) values were lower than 1 bpm in QB and 5.50 bpm in T. In the standing position, the maximum MAE found was 1.05 bpm in QB and 3.10 bpm in T. Lastly, an MAE lower than 1.60 bpm was found while walking. These promising results were in line with what was found in the literature.