Integrated Heart‑Rate Sensors in Smart Clothing: Reliable Wearable Monitoring

Stretchable, bendable “smart” textiles are poised to reshape clothes of all kinds, creating new opportunities for integrating advanced monitoring technologies into everyday items. Researchers are applying neuroscience and psychophysiology to build responsive technologies like those integrated in smart textiles. They found that wearable sensor systems don't seem to perform as well in monitoring heart rates as traditional electrodes.

To solve the problem, the researchers tested the feasibility of electrocardiogram (ECG) monitoring with sewn textile electrodes instead of traditional gel electrodes in a three-lead, chest-mounted configuration. Commercially available wearables are usually incapable of detecting the full ECG waveform.

Approaches included conductive ink-based electrodes printed onto the fabric surface that tend to crack, causing breaks in the conductive surface and changes in resistance during movement. They also explored planar-fashionable circuit boards (P-FCBs), which similarly print onto the fabric surface but require advanced manufacturing methods to produce the conductive paste.

The solution the team devised involved fabricating “dry” electrodes that are directly integrated in clothing. Because the device conforms to the skin, it avoids noise and artifact issues that normally occur due to the motion of similar dry electrodes across the skin.

Performance was undiminished after the device underwent a battery of validation tests, including ECG monitoring, comfort surveys with human subjects, stretch testing, and wash cycling. Device performance matched the traditional electrode in being able to detect the full ECG waveform.