The next Apple Watch may monitor blood pressure, blood glucose, and blood alcohol levels, according to the rumors. The watch already monitors your heart rate, your movement, environmental noise, and even your blood oxygen levels. Alone, these are interesting enough, but taken together, in a watch that is almost always on your arm, they can revolutionize healthcare. “The possibilities for sensors that can be included in a watch are practically endless, but Apple’s approach is to create a near-perfect product before putting it in a production watch,” Vardhan Agrawal, software developer and co-creator of the BP-lytic cuffless monitor, told Lifewire via email. “Chances are, we won’t be seeing these technologies in our own watches until they are ripe.”

Accuracy

The new sensors come from UK startup Rockley Photonics, and can measure blood pressure without an inflatable cuff. “Apple is rumored to be using a seismocardiogram, which measures microscopic movements in the heart’s rhythm,” says Agrawal. “Since this is different from techniques traditionally attempted for continuous blood pressure monitoring in the past (pulse-transit-time for instance), it’s expected that it might be more accurate.” There are already plenty of watches and wrist-worn medical devices that can monitor blood pressure. The $500 Omron HeartGuide, for example, contains an inflatable cuff in its strap. That’s a proper medical device, but it lacks all the other features that make the Apple Watch great. In some ways, it seems like the Apple Watch will render all kinds of wrist-mounted gadgets obsolete in the same way the iPhone did with cameras, iPods, pocket game consoles, and (ironically) watches.

Constant Care

Usually, you only ever get your biometrics measured when you visit the doctor. Constant monitoring has obvious advantages over this, even if the overall accuracy is lower (which is not necessarily the case). “The advantage of continuous monitoring of blood pressure comes in the form of trends,” says Agrawal. “For patients with essential hypertension, for instance, it’s important to assess the factors which cause changes in one’s blood pressure. A single reading at a doctor’s office isn’t considered enough.” If your watch is constantly monitoring your vital signs, then it also can flag anomalies. Legalese warnings notwithstanding, the Apple Watch makes for quite an effective early-warning system. It even detects falls and notifies the emergency services if you remain unresponsive. Constant monitoring “in the field” also can be more accurate, not less, suggests Agrawal. “Factors such as white coat hypertension, or masked hypertension, can cause single readings to be falsely elevated or reduced for psychological reasons,” he says. That’s when your physiological response changes because there’s a doctor taking your measurements.

Other Sensors?

The other sensors rumored for the next Apple Watch measure blood glucose and blood alcohol levels. The former would be amazing for both diagnosis and management of diabetes, while the latter would clearly be handy for watching what you drink when driving. Thanks to the likely legal complications, you’ll probably never get an app that tells you it’s safe/not safe to drive, but perhaps it could be a deterrent. Another very useful monitor would be body temperature. Right now, you can pair an app with a smart thermometer, but what’s the point? You may as well use a cheap, regular thermometer. Temperature sensing is always handy for general ailment diagnosis, but might be especially handy now, as an indicator for COVID-19 infection. Medical monitoring has become one of the main pillars of Apple Watch functionality, so we can expect it to continue. Although, to be honest, this reporter would be happy if Apple replaced that digital time readout that appears whenever the display sleeps over an active app.