Here’s how Google just turned earphones with ANC into a heart-rate monitor

Earphones, with Active Noise Cancellation (ANC) capabilities, don’t just allow you to drown out the world around you. Google, as it turns out, just turned earphones with ANC capabilities into a heart-rate monitor. Intrigued? Read on to find out how.

Audioplethysmography: What it is and how it works

Google, in a paper titled “APG: Audioplethysmography for cardiac monitoring with hearable devices,” suggests that heart-rate sensing capabilities can be added to ANC headphones and earphones via a software update.

According to the company, the ear canal is the ideal location for tracking health parameters. It says that the deep ear artery forms a network of vessels that are spread throughout the auditory canal.

How the APG approach works, is by sending a low-intensity ultrasound probing signal into the auditory canal, through an ANC headphone’s speakers. This in turn triggers echoes, which are received via feedback microphones. What this does, is cause tiny displacements of the ear canal’s skin, and one’s heartbeat also modulates these echoes. That is to say, the heart rate influences how these echoes behave and are received.

Another model which Google created, then works to process that into a heart-rate reading. Not just that, it also measures one’s heart-rate variability. The technique, as per Google, works even when music is playing, or if the earbud has bad seals. The only factor that affects the reading from the same is body motion.

ALSO READ: Dyson Zone headphone launched in India for health-conscious music lovers

That’s not all. The APG approach is also not impacted by one’s skin tone, or ear canal size either. The fact that it can be installed via a software update, also means that traditional photoplethysmograms (PPG) and electrocardiograms (ECG) sensors, need not be fitted in earphones.

To test the same, Google performed two sets of the same study with 153 people. It found that APG achieved a minimal 3.21 per cent median error rate across the sample, when it comes to heart rate. The median error rate, when it came to heart rate variability, stands at a mere 2.7 per cent, in inter-beat interval measurements.

With this study, Google may have revolutionised personal health monitoring once and for all and proven that wearable audio tech can do way more for us, than we previously thought.