Development of Non-contact Ubiquitous Monitoring System Embedded into Chair and Bed for Continuous Cardiac Monitoring

Workplace stress and fatigue due to long working hours and prolonged cognitive workload has been reported to be a significant predictor of cardiovascular diseases. Continuous monitoring of cardiac activity could provide to be a way to identify the early onset of stress and fatigue. However, the discomfort brought by ECG measurement electrodes has been a challenge for long term ubiquitous monitoring at the workplace. In this study, we have developed tin-coated copper active electrodes embedded onto a mat that can be fastened to an office chair or bed allowing unobtrusive measurement of cardiac activity. The experimental results from filtering and R peak detection of cECG measurements show high accuracy, and the heart rate calculated had a very high correlation with the conventional ECG measurements for both chair (r = 0.991, p < 0.01) and bed (r = 0.981, p < 0.01) form factors. The decrease in the mean squared error of computed heart rates from cECG measurements on chair (MSE = 0.43 bpm) could be attributed to increased lumbar contact as compared to lying down on bed (MSE = 1.13 bpm). The developed cECG sensor and measurement system could be seamlessly integrated into everyday objects such as chair, bed and car seat for unobtrusive cardiac monitoring with no prior preparations. Further heart rate variability studies to identify the markers of changes in sympathetic nervous activity could provide an early indicator of stress and fatigue to promote an active and healthy lifestyle in the workplace.