Fitbit has registered a patent for a wearable device that can measure the health of your arteries, and pick up early signs of high blood pressure.
The patent listing (opens in new tab) (spotted by Gadgets & Wearables (opens in new tab)) was registered on December 4, is brief, but describes how a device like a wrist-worn fitness tracker could be used to measure the stiffness of your arteries non-invasively.
It wouldn't require an extra sensor; instead, it would use the optical heart rate sensor already included in all current Fitbit devices. This would detect changes in blood flow during exercise, which could then be analyzed to estimate pulse wave velocity – the rate at which waves of pressure move through your arteries.
If your pulse wave velocity is particularly fast, it's an indication that your arteries aren't as flexible as they should be, and therefore can't expand as blood is pumped from your heart. It also means higher blood pressure (or hypertension), which is a leading cause of heart disease and stroke.
This is the same tech used in the Withings Body Cardio, which we reviewed earlier this year and ranks highly in our guide to the best smart scales, as well as several Samsung Galaxy smartwatches (opens in new tab).
Measuring pulse wave velocity is easier with a scale, since the person is standing still. A wearable has to factor in 'noise' caused by body movement tha could distort the readings, but although Fitbit has its own line of smart scales (the latest of which, the Aria Air, was released in 2019), the new patent relates specifically to wearable devices.
Since it doesn't require additional hardware, it's possible that pulse wave analysis could come to existing Fitbit devices in the form of a software update.
We wouldn't expect it for a while though; a patent registration isn't a guarantee that a feature will ultimately be released to market, and after development and testing, it need to be approved by the US Food and Drug Administration, as well as the relevant authorities in other countries where the device is sold. We'll keep you updated as soon as we know more.
Analysis: early detection matters
Fitbits aren't medical devices, and the company makes it clear that they can't be used to diagnose or treat any illnesses, but they can still be useful for picking up early indications that something is amiss.
The Fitbit Sense and Charge 4 both have eletrocardiogram (ECG) sensors that can pick up signs of atrial fibrillation (an irregular heartbeat) that should be investigated by a doctor, devices with SpO2 sensors can detect unusual drops in blood oxygen saturation overnight that might be a symptom of sleep apnea.
If you're worried, the app can take this data and turn it into a PDF report that you can share with a family member or doctor.
More recently, Fitbit has taken part in a study (opens in new tab) that suggests data from its fitness trackers could help identify early signs of Covid-19 infection before a person starts to show symptoms.
Hypertension is known as 'the silent killer' due to its lack of symptoms in its early, most treatable stages. Millions of people wear a Fitbit device every day to to monitor their daily steps and exercise habits; if that device could also pick up signs of high blood pressure, it has the potential to help save lives.
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