Google’s latest Pixel-exclusive feature is the ability to track heart rate and airways without additional hardware. The company says that starting next month, Google Fit on Pixel phones will track health statistics using only the device’s existing cameras.
We’ve seen heart rate tracking on smartphones before thanks to Samsung’s Galaxy line. From Galaxy S5 to Galaxy S10, Samsung tracks heart rate through a physical photopetysmography sensor (PPG) on the back of the phone. Users can just press a finger against the sensor and get a heart rate reading in seconds.
Pixel phones do not have a PPG, but Google’s solution is not that different. A PPG shines a light (usually a green LED) into your skin, which is reflected by the bloodstream back to a nearby photoreceptor. It is basically a specialized camera. Google’s Pixel solution uses only the camera. Google says, “To measure your heart rate, simply place your finger on the rear-facing camera lens.”
Calculation of breathing rate using the front camera. Google’s instructions (shown in the gallery above) say to support your phone against something, turn on the selfie camera, and as long as your head and upper body are in sight, you will be able to get heart rate and respiratory rate reading.
Our takeaway from the previous Samsung smartphones was that heart rate tracking is best left to smartwatches and exercise trackers. Wearables are allowed to be in contact with the arm at all times and can passively track your heart rate while exercising or walking during the day. The phone-based solution requires you to stop what you are doing, open an app, press your finger on a sensor and hold still for a few seconds while it measures. On Samsung phones, this was a problem and definitely not something you want to do in the middle of a workout. Samsung eventually gave up on the feature as well by cutting the PPG sensor from the Galaxy S20, and no one really missed it. The feature makes a little more sense when it’s “free” and does not require special hardware, but we will still only strap on a training track, especially when decent 24/7 PPG trackers are available for $ 30.
Google says both of these features track “small pixel-level physical signals – such as chest movements to measure your breathing rate and subtle changes in the color of your fingers for your heart rate.” Google told The Verge that the heart rate sensor is accurate within 2 percent. The company does not have FDA approval for any of these new features, so they are for “general well-being” only and cannot be relied upon for a medical diagnosis or to evaluate medical conditions.