On Pixel phones, Google is adding heart and respiratory rate monitors to the Fit app, and it plans to add them in the future to other Android phones. By measuring the rise and fall of a user’s lung, and heart rate by monitoring color change as blood flows through the fingertip, it monitors respiratory rate.
Users focus the phone’s front-facing camera at their head and chest to calculate the respiratory rate (the number of breaths someone takes every minute) using the app. They place their fingers over the rear-facing camera to measure the heart rate.
The heart rate monitor from Google is similar to a feature included by Samsung on a range of older Galaxy smartphones, including the Galaxy S10.
Google’s app heart rate data would be less accurate than the kinds of readings someone might get from a fitness tracker that can track anything like heart rate on an ongoing basis as someone goes about their daily lives.