Google is set to revolutionize the world of wearable technology with its pioneering research into audio plethysmography (APG). 

This innovative technology promises to equip active noise canceling (ANC) headphones and earbuds with heart rate monitoring capabilities through a straightforward software update. In this breakthrough, Google harnesses the inner ear's unique properties for health sensing, ushering in a new era of convenience and accuracy in tracking vital signs.

Highlights:

Ear Canal as Ideal Health Sensor: Google has identified the ear canal as an optimal location for health sensing due to the intricate network of vessels within. This revelation paves the way for accurate heart rate monitoring.

Ultrasound-Based Heart Rate Measurement: Google's technology relies on a low-intensity ultrasound signal sent through ANC headphone speakers. It analyzes echoes, capturing minute ear canal skin movements and heartbeat vibrations to derive heart rate readings and heart rate variability.

Robust and Accurate Results: Google's APG technology delivers consistently precise heart rate measurements, unaffected by factors like skin tone, ear canal size, and suboptimal seal conditions.

In a recent blog post, Google unveiled its groundbreaking work in audio plethysmography (APG), introducing a method to infuse heart rate monitoring capabilities into ANC headphones and earbuds through a software upgrade. Google's research emphasizes the ear canal's unique attributes for health sensing, where the deep ear artery weaves a complex network of smaller vessels throughout the auditory canal.

APG operates by transmitting a low-intensity ultrasound signal through the speakers of ANC headphones. Echoes generated are captured through onboard microphones, with the vibrations of the ear canal skin and heartbeat modulating these echoes to yield heart rate and heart rate variability readings.

The company has developed a model that processes this feedback, even in scenarios with "bad earbud seals." Google encountered challenges related to body motion but mitigated them through a multi-tone approach. This calibration tool identifies the most suitable frequency for accurate heart rate measurement.

Google conducted two studies involving 153 participants, highlighting APG's consistently accurate heart rate (3.21% median error) and heart rate variability (2.70% median error) measurements. Unlike conventional heart rate sensors, APG remains unaltered by skin tones and ear canal size, making it a versatile, cost-effective, and reliable solution for health sensing. This technology promises to transform TWS ANC headphones into intelligent sensing devices with a simple software update, advancing biomedical and mobile research while offering low-cost health sensing possibilities.