Some apps promise to measure blood pressure entirely without any auxiliary tools. But is this really possible? We examined how these apps are supposed to work and whether they can deliver their promises.
That's how it works
Some apps promise to measure blood pressure, only by using the iPhone’s camera and microphones. The measuring procedure usually looks like this: First, the right index finger must be placed on the lens and the flash of the iPhone’s camera. Then the bottom of the iPhone, more precisely the microphone, must be pressed with direct contact to the chest. This position then must be maintained until the result of the measurement is concluded.
We have made it our mission to put these apps to a fact check. Unfortunately, most of these apps have disappeared from the European app stores. Therefore, it was not possible for us to test the apps ourselves.
Nevertheless, we have checked the available facts online. Generally speaking, blood pressure measurement works the same way in all commercially available devices: the inflation of the cuff makes it possible to measure the vibrations of the arterial walls. How the apps are supposed to work is not specified.
Let's move on to the facts: in 2016, the Johns Hopkins University School of Medicine published an independent test of one of these apps, Instant Blood Pressure, with devastating results. For example, 77.5% of all patients with hypertension (blood pressure values above 140/90 mmHg) were found to be inaccurate. Overall, the measured values by the app differed from the real values on average by 12.4 mmHg systolic and 10.1 mmHg diastolic.
In addition, the company behind this app was sued in 2016 by the US Federal Trade Commission (FTC) due to false statements in the distribution and marketing of the App. The indictment was later resolved in a settlement.
This shows that the methods available to the iPhone are not yet sufficient for reliable medical readings.
Blood pressure monitors with Bluetooth
A trusted alternative for monitoring blood pressure on the iPhone are blood pressure monitors with Bluetooth and Apple Health Integration. These devices typically deliver blood pressure readings via Bluetooth to the chosen health apps, which in turn can be shared with apps like Cora Health using the Apple Health interface.
Tip: The Cora Health app helps you track your blood pressure and encourages you to improve your heart health through scientifically-backed lifestyle recommendations.
Measuring blood pressure with the Apple Watch
At the moment, blood pressure can not be measured reliably with the Apple Watch, just as with the iPhone. However, rumors and patent applications are increasingly suggesting that Apple is developing wristbands for the Apple Watch that can measure health data such as blood sugar levels and blood pressure. At the moment, however, we will have to wait until Apple reveals information about these innovations.