Google researchers leverage off-the-shelf headphones for innovative heart-rate monitoring

Google's research team has introduced a pioneering method for monitoring heart rates using commonly available noise-canceling headphones.

Traditional heart rate tracking in wearables relies on photoplethysmography (PPG), which uses light pulses to measure blood activity. In a recent research blog, Google scientists unveiled an alternative approach called audioplethysmography (APG), leveraging ultrasound technology to measure heart rates. This innovation has the potential to revolutionize the way we monitor our vital signs.

The APG method involves bouncing a low-intensity ultrasound signal off the inner ear canal and using the headphone's microphone, typically utilized for noise cancellation, to detect subtle skin surface movements caused by blood circulation.

Impressively, this technique proved "resilient", even when users experienced issues like an imperfect ear seal, variations in ear canal size, or darker skin tones, addressing a longstanding challenge faced by previous wearables in achieving accurate heart rate measurements in individuals with darker skin tones or tattoos.

Although the APG demonstrated effectiveness even when playing music, it had problems in noisy environments and was sensitive to noise caused by body movement. However, the researchers overcame these problems by utilizing multiple frequencies and isolating the most accurate signal.

This breakthrough in ultrasound-based heart rate monitoring promises more reliable and inclusive solutions for wearable devices, although it is important to note that its implementation in consumer devices may require further development and testing.