Adding blood pressure readings from a smartwatch or other wearable fitness device can make life better.
- A friend recently said that her pretty fit and healthy boyfriend didn’t know that he has astronomically high blood pressure and that he now has to reconstruct his life for his health.
- If his everyday wearable had given him a tip earlier, it might have been helpful.
The problem? Get reliable blood pressure results from smartwatches. It’s good enough for South Korea right now, but the U.S. Food and Drug Administration still hasn’t approved it.
The Verge’s Nicole Wetsman has some really good information on why this is, with insights from researchers and doctors:
- “‘We’re not ready for prime time just yet,’ says Jordana Cohen, an assistant professor of medicine at the University of Pennsylvania who studies hypertension.”
- There is currently only one Food and Drug Administration-approved handheld device for measuring blood pressure: a device from medical device manufacturer Omron.
- “Omron’s HeartGuide is extremely specialized. It is even being marketed as a ‘portable blood pressure monitor in the innovative shape of a wristwatch’. ”It takes the normal pressure approach you may have had through a doctor or nurse to measure blood pressure.
Samsung and Fitbit devices and so on use light sensors, but the FDA is still reviewing them:
- Samsung’s approach is based on a measurement called pulse transit time, which is the time between when the heart contracts and when the pulse arrives at a specific part of the body, such as the wrist. It correlates with blood pressure. “The faster the pulse transit time, the more the vessels contract – that makes the pulse faster,” says Mendes. Optical sensors also check whether vessels contract or expand. An algorithm then uses these two bits of information along with the heart rate to estimate blood pressure.
- Fitbit is a few steps back in the process – no blood pressure features are available, but a handful of studies are underway to examine the relationship between the readings already collected by its devices and blood pressure.
- Limitations are that they can only reliably measure relative blood pressure. The devices must be calibrated in order to find a true number in order to assign rising and falling blood pressure values to a “raw number”, not just the current number.
- Eric Friedman, Fitbit’s vice president of research, says it will be a Herculean solution: “Whole books have been written about why this is an impossible thing to solve.” he says. “I don’t have the hubris to see it as something that comes out every day now.”
Why is it so important? Why can Tesla run beta software while blood pressure insights are so protected?
- “High blood pressure is such an important risk factor for stroke, major cardiac events and kidney disease,” says Jordana Cohen. “It is so, so important that we get it right because if devices give you an inaccurate reading, you can very falsely assure you that your blood pressure is normal.”
