Google Pixel users no longer need a smartwatch to measure heart rate and breathing, thanks to a new upgrade to the Google Fit app.

Google announced last month that the upgrade will be available for Pixel phones and will allow users to measure breathing and heart rate via the camera. That functionality is now being rolled out to "compatible Pixels" through an update to the Google Fit app.

We already knew that this was a timed exclusive feature to Pixel phones and that the feature would arrive on other Android devices at a later date undefined, but the word "supported" is still interestingly vague here.

Does this mean all Pixel devices that can physically run the software, or does it mean devices that are still officially supported by Google? If the latter, it would exclude the Pixel 2 and Pixel 2 XL, whose support expired last October.

This feature gives Pixel users a way to check their heart rate and breathing. To measure heart rate, users place their fingertips over the rear camera and analyze subtle color changes in the skin to read the pulse. Google's tests show that it is 2% accurate, but it is clearly designed for one-time testing and is not constantly updated like the best smartwatches.

Breath tracking, on the other hand, uses the front-facing camera. When the phone is placed in front of the head and torso so that the head and torso are visible, the app calculates the number of breaths per minute after monitoring chest movements. Google claims that tests have proven accurate to within one breath per minute. However, the company emphasizes that neither the app nor the heart rate measurement is for medical purposes.

Despite this, Google is clearly quite confident in the accuracy of its technology, which should give it an edge over the various apps that claim to do the same thing, without any real scrutiny.

"We have developed both features and completed initial clinical trials to validate them. For example, our heart rate algorithm relies on estimating blood flow from changes in fingertip color, so for it to work for everyone, it needs to take into account factors such as lighting, skin color, and age."

If you have a Pixel phone, you can try it yourself today; stay tuned for updates to the Google Fit app and let us know how it works for you.