Once it reaches “100%”, you will be shown the results on a different screen, as well as your weekly average RPM. If something feels sketchy, you can take your measurements again by tapping a “+” button.
Google’s algorithms can, apparently, count the number of breaths you take based on the movements of your chest cavity.
As for heart rate monitoring, Pixel phones will handle that with the rear camera by asking the user to place their finger on the lens. The differences in blood flow will tell the device your heart rate.
Both measurements will take about 30 seconds of your time, each. That’s not incredibly fast (not when compared to smartwatches, at least) but if you don’t have anywhere to be, that won’t annoy you too much.
While Pixel phones will get the update first starting next month, Google promises to bring these features to more Android handsets soon.