Blood pressure is an important indicator for drawing conclusions about general health, kidney function or the risk of a heart attack.

The easiest way to measure blood pressure is with a blood pressure cuff. However, this only provides a reliable value at a specific point in the body, primarily the upper arm, at a specific time. Long-term measurements at two or three points, on the other hand, would be more helpful.

Blood pressure measurement already exists in a compressed form. Quite a few smartwatches advertise this capability. However, tests show that even the best models do not provide reliable data without regular calibration using a blood pressure cuff.

Sound instead of pressure

A completely new technology, developed at Caltech, is intended to solve this problem. A sound wave is sent via the device into the underlying artery. This creates a resonance that is then precisely measured using ultrasound. All you feel is a slight tingling sensation on the skin. The whole thing is called resonance sonomanometry.

As a result, both the systolic and diastolic blood pressure values are obtained with the same reliability as with a blood pressure cuff. And even though the device is currently still the size of a Raspberry Pi, there is confidence that the whole thing can be compressed to the size of a smartwatch.

The current prototype already has a few remarkable features: the artery is automatically localized and targeted. Even with low blood pressure, there are no problems with the measurement, unlike with other technologies.

So there is a good chance that it will soon be possible to record the correct blood pressure more easily and reliably. And that the whole thing can be used not only for self-optimization, but actually for good health care.