Google has recently unveiled its groundbreaking research into audioplethysmography (APG), a technology that allows active noise canceling (ANC) headphones and earbuds to monitor heart rate with a simple software upgrade.
The Ear Canal: An Ideal Location for Health Sensing
Google’s research highlights the ear canal as an ideal location for health sensing, thanks to the deep ear artery’s intricate network of smaller vessels that permeate the auditory canal.
How APG Works: Ultrasound Probing Signals and Echoes
The APG technique involves sending a low-intensity ultrasound probing signal through the speakers of ANC headphones. These signals trigger echoes that are received by on-board feedback microphones.
Accurate Heart Rate Readings and HRV Measurements
Google’s model processes the feedback received from the echoes to provide accurate heart rate readings and heart rate variability (HRV) measurements. This technology can even function while music is playing and despite less-than-optimal earbud seals.
Overcoming Motion Interference: The Multi-Tone Approach
To address the challenge of body motion interfering with accuracy, Google developed a multi-tone approach as a calibration tool. This method helps identify the best frequency for measuring heart rate, ensuring high-quality pulse waveform data.
Validation Studies: Consistently Accurate Results
Google conducted extensive studies involving 153 individuals to validate the effectiveness of APG. The results were impressive, with APG consistently achieving accurate heart rate measurements and reliable HRV measurements across various activity scenarios.
Advantages Over Traditional Sensors: Skin Tone Independence and Accessibility
APG offers advantages over traditional sensors, as it is not influenced by skin tones and is not affected by factors like ear canal size or sub-optimal seal conditions. This software-based approach eliminates cost, weight, power consumption, acoustic design complexity, and form factor challenges.
Unlocking New Possibilities: Low-Cost Health Sensing
The introduction of APG represents a significant advancement in biomedical and mobile research, unlocking new possibilities for low-cost health sensing. By transforming any TWS ANC headphones into smart sensing devices through a simple software upgrade, Google has paved the way for enhanced health monitoring in everyday audio accessories.
Collaboration and Future Integration
Google highlights that APG is the result of collaboration across multiple teams, including Google Health, product development, user experience, and legal departments. While the potential integration of this technology into Pixel Buds is exciting, its availability is not yet guaranteed.