Smart sensing of cardiovascular physiological information from soles without direct skin contact.

This study proposes the development of a smart sensing measurement system using a mat-type sensor in order to obtain sole-electrocardiogram data from soles and toe-photoplethysmogram data from toes. In addition, the proposed measurement system can calculate pulse wave velocity from sole-ECG and toe-PPG. The subjective experiments revealed that the developed system can measure these parameters even when socks are being worn. Moreover, simultaneous measurements of systolic blood pressure and PWV determined by the developed system indicate a strong correlation was found between SBP and PWV. Therefore, this system can detect cardiovascular diseases or symptoms of common diseases and suggests the possibility to estimate the temporal changes in SBP without required compression using cuffs.