Wearable Sensors for Cardiorespiratory Monitoring Based on Chest Wall Motion and Their Applications

This article reviews wearable solutions for cardiorespiratory monitoring that leverage chest wall motion as the primary sensing mechanism. The most popular sensing technologies are categorized into two main groups based on the underlying measurement principles: systems that rely on changes in physical dimensions (i.e., strain and quantities that cause strain) and those based on inertial measurements (i.e., accelerometers and gyroscopes). For each available solution, the article provides an in-depth analysis of the working principle, design and fabrication of the sensing part, integration onto the wearable systems, and key application scenarios, along with performance evaluations of these systems in each context. In addition, this review outlines the state-of-the-art algorithms and signal processing techniques used to estimate cardiorespiratory parameters, such as respiratory and heart rate, and other cardiorespiratory variables from sensors’ output. Current limitations and future trends and challenges are also discussed, aiming to guide further innovations and improve the practical usability of these wearable monitoring systems.