Fitbit is looking into whether some of its existing fitness trackers can be used to measure blood pressure, and is asking its users to help with that. The study, conducted by Fitbit Labs, looks at whether the Fitbit Sense can measure pulse arrival time (PAT), which is the time it takes for a blood pulse to reach your wrist after your heartbeats. This is not a direct measurement of blood pressure but could be a useful proxy.
Fitbit says previous research has found a correlation between the two values, but the correlation in these studies was not strong enough to accurately predict blood pressure. These studies were limited to either small data sets or specific environments such as intensive care units.
Fitbit Labs also found a correlation between PAT and blood pressure in a small, three-week internal study, and now wants to expand its research to look at a larger study group, in a variety of situations. Participation is optional, but if you own a Fitbit Sense, are at least 20 years old, and live in the US, look out for an invitation asking you to participate by contributing your data.
High blood pressure (also known as hypertension) often goes undetected and can lead to serious health problems such as heart attacks and strokes if left untreated. It is usually only noticed by a doctor using an inflatable cuff worn around the upper arm (a sphygmomanometer).
People who have already been diagnosed with hypertension are advised to measure their own blood pressure at home in this way, often twice a day, but a 2020 survey by the Valencell company that produces wearable adults sensors found that 31 percent of American with hypertension measure their blood pressure only once a month, and another 31 percent admit to measuring blood pressure once a year.
A device that can be worn every day like an ordinary wristwatch and can take measurements with minimal effort on the part of the user could therefore be a potential lifesaver by detecting dangerous changes early.