Google tests whether your smartwatch can catch high blood pressure

An ordinary smartwatch may help more people discover high blood pressure. Google Research has developed an AI that uses the watch's heart rate sensor and motion sensor to find signs of elevated blood pressure. No blood pressure cuff is needed to calibrate the measurements.

According to Google, more than half of those with elevated blood pressure do not know they have it. Google's product page puts it at six in ten people who do not notice when their blood pressure has risen.

How the AI was trained

According to the news site The Decoder, a neural network was trained on nearly 500,000 hours of sensor data. A neural network is a type of AI that learns patterns by looking at many examples. Here, it compared short segments of data and decided which ones came from the same person. In this way, it learned typical heart rate and heartbeat patterns without help from diagnoses.

The system then calculates an average of the patterns over several days and works out a probability of elevated blood pressure.

What did the test show?

In a study of 196 people at five research sites in the US, the smartwatch identified 65.8 percent of those with elevated blood pressure. The standard measurement at the doctor's office identified 55.3 percent. The figures come from The Decoder, which reports that the study was published in Nature. The sources do not make clear which blood pressure threshold or which measure underlies the percentages, or whether the difference is statistically significant. The results are Google's own research.

The feature has not launched yet

According to The Decoder, Google has built the results into the Blood Pressure Trends feature in the Google Health app. However, Google's own announcement says the Health Guardian features are coming soon. According to Google's product page, the feature uses heart rate and movement patterns collected passively over a month. It is based on the WavesFM model, which is trained on billions of minutes of raw heart and movement data.

Google stresses that the method is still a research project and that it does not replace a diagnosis. The product is intended only for general wellness and must not be used in place of professional medical care. The goal is to get people to get checked.

For the reader, this means a smartwatch may eventually offer a practical hint that it is time to have your blood pressure measured by a doctor. It cannot give an answer on its own.