Google Fit for iOS has reportedly gained the ability to track and measure heart and respiratory rate using an iPhone’s camera. The fitness app can measure a user’s heart rate when they apply light pressure on the rear camera lens. It can also work if the user’s smartphone doesn’t have an active internet connection. The front camera, on the other hand, tracks a user’s breaths per minute (BPM). Google Fit’s heart and respiratory rate tracking feature was first introduced for Google Pixel smartphones in February.

9to5Google reported that Google Fit on iOS is receiving heart and respiratory rate measurement features. Google tracks subtle movements in a user’s body to measure their heartbeat and BPM.

Google Fit measures a user’s heart rate when they place a finger on the rear camera sensor and apply light pressure. If a user is in a low light environment, the fitness tracking app can use the smartphone’s flash to increase accuracy. Alternatively, users can place their hand and iPhone handset in front of a light source. Google measures the heartbeat by tracking “subtle changes in the colour of your fingers” to approximate blood flow. The heart rate algorithms also account for lighting, skin tone, age, and other such factors.

The heart-rate measurement takes approximately 30 seconds and previews a graph with beats per minute (BPM). Once the process is complete, the user has the choice to save the vitals to Google Fit.

Also with Google Fit for iOS, the selfie camera of an iPhone can track a user’s respiratory rate by tracking their breaths per second. For this to work, users need to keep their phone steady and stable with their head and torso clearly visible in the app’s display. Prompts on the screen guide the user to “hold still” for about half a minute. Subtle chest movements with computer vision tracking tiny physical movements measure the user’s respiratory rate.

Alternatively, measurements on Google FIt can also be initiated by heading to the Browse tab and clicking on Vitals. Users also have the option to set reminders for measurements.

9to5Google mentioned that they were able to view the new heart and respiratory rate measurements on iPhone 7 and iPad Pro. The report also said that if users have recently downloaded Google Fit and it doesn’t show the new cards, closing the app from the multitasking screen and reopening should make it work.

Google first introduced heart and respiratory rate measurement features for Google Fit in February. The features were initially released for Pixel smartphones, reaching other Android smartphones eventually.