Measuring your heart rate by looking at your smartphone, the new idea from Google

To monitor your health on a daily basis, there's nothing like a connected watch or bracelet. Their sensors record a whole bunch of useful measurements for athletes, but not only that. Sometimes just knowing your heart rate can help identify stressful situations or convince you that a little rest would do you good.

Problem: not everyone has such an accessory on their wrist. On the other hand, almost everyone has a smartphone. Based on this observation, Google developed Passive Heart Rate Monitoring (PHRM), or passive heart rate monitoring. Nothing to do with the system of the 2010s based on the rear camera and flash. You don't have to do anything here.

How your smartphone could discreetly measure your heartbeat

The keystone of the system is the front camera of your mobile. When you unlock it using facial recognition, it records an 8-second video of you. An AI algorithm then analyzes the variations in the skin caused by the circulation of blood in the body. These are what make it possible to determine the heart rate. The process is carried out directly on the device to avoid data leaks.

After more than 350,000 videos on around 700 participants (with skin tones from light to dark), the results are in. The PHRM meets current measurement standards set for smart watches and bracelets. The difference with a Fitbit Charge 6, renowned for its precision, is only 5 beats per minute for example.

Encouraging, but not yet perfect. Particularly on dark skin, the measurements are sometimes inconsistent. Additionally, moving your head or speaking while recording video can distort the results. Pitfalls on which Google still needs to work.