Adding a blood pressure monitor to smartwatches could arguably be more important for users’ cardiovascular health than the heart rate and rhythm monitors they have now, says says Ann Marie Navar, a cardiologist at the University of Texas Southwestern Medical Center.

Having more ways to easily take blood pressure measurements at home could be a big benefit to people with hypertension (high blood pressure) or other concerns.

Pressure measurements taken exclusively in a doctor’s office are often unreliable: some people have higher blood pressure in-office because they’re anxious about the visit, while other people have masked hypertension — high blood pressure at home, but normal blood pressure at the doctor.

“We don’t pick it up unless we have people check their blood pressures at home,” Navar says.

Right now, there’s one wearable device cleared by the Food and Drug Administration to measure blood pressure: a device from medical equipment company Omron, which has an inflatable cuff inside the band that lets it take blood pressure measurements at the wrist using the traditional squeezing method.

Mendes could strap a watch on and find out if someone’s blood pressure was higher in the morning than it was when they went to sleep the previous night, but wouldn’t be able to tell what the raw number it started at was without benchmarking the device off of a standard blood pressure cuff.

It would reportedly just give people information on trends in their blood pressure — if it’s increasing or decreasing — rather than a raw measure, which requires the calibration step used by Samsung, according to The Wall Street Journal.

That’s a more realistic approach, Cohen says, because the techniques used in smartwatches are much more capable of detecting relative changes in blood pressure.

The sensors currently common in smartwatches probably won’t be able to measure blood pressure without calibration against an outside cuff, Mendes says.

Even if companies can’t directly measure blood pressure through a watch, they might be able to use metrics like pulse arrival time to give people information about swings in their blood pressure (like Apple is reportedly pursuing) or their general fitness levels.

There’s more and more data available on non-cuff blood pressure monitors — movement in the right direction, Navar says.

Clinicians will have to carefully examine any new device on the market to make sure it’s working well enough to trust in different groups of people, including people with high or abnormal blood pressure, Navar says.

Blood pressure is relatively easy to double check with a medical-grade cuff at home or in the doctor’s office, Navar says

“I’d probably want to make sure that, if somebody is using one of these watches to measure their blood pressure, that we check it against a more standard measure,” she says