Are smartwatches and bracelets the future of blood pressure monitoring?

The pros and cons of taking your blood pressure from your wrist

According to According to the World Health Organization , one in four men and one in five women worldwide has high blood pressure or hypertension. This can put them at higher risk of heart attack and stroke.

Hypertension has symptoms, such as headaches and changes in vision, but many people do not experience them diagnosis and treatment are often delayed. That's why it's so important for everyone to measure their blood pressure regularly – especially those at high risk.

The standard way to detect hypertension is to use apparatus for measuring blood pressure or, more formally, a sphygmomanometer. The device uses a cuff that is worn on the upper arm and is tightened to restrict blood flow. This allows the pressure sensors inside to measure the force with which the blood presses against your arteries as it is pumped from your body – your blood pressure.

This method is relatively easy and accurate, so why do we need new solutions?

Problems with measuring blood pressure

Experts recommend that people with hypertension measure their blood pressure twice a day. But a study by 2020 from the company Valencell found that 31 percent of US adults with hypertension take their blood pressure only once a month, another 31 percent admit to taking it once a year. This may be due to patients forgetting or not having the necessary equipment at hand.

"We often don't have the time or the ability to take blood pressure readings," says Jordana Cohen, MD, an assistant professor of medicine and epidemiology at the University of Pennsylvania who specializes in hypertension research.

For example, if a patient starts a new medication, ideally they should have multiple measurements on the same day and over the next few days to gauge how their body is responding – but this often doesn't happen.

Dr. Cohen explains that there are also a number of specific conditions to consider that make the traditional measurement of blood pressure unreliable. These include "white coat hypertension," when someone's blood pressure is elevated when they are around doctors but not at home. Masked hypertension, when readings may be good in the doctor's office but elevated at home. Or nocturnal hypertension, when blood pressure rises during sleep.

You can buy one of the standard blood pressure monitors with a cuff for home use. This is the reality for many people currently living with hypertension.

Those with long-term hypertension may also need so-called ambulatory blood pressure monitoring (ABPM). ). In this case, a doctor provided them with a portable blood pressure monitor with an all-day cuff. The cuff takes readings every half hour and stores them.

But measuring blood pressure with a cuff, whether in a medical facility or at home, is inconvenient for many reasons: it can't be done at night, it can raise blood pressure levels when the cuff is overinflated, and it can be difficult for daytime wear for those who work and are on the move, for the disabled or the elderly .

That's why wearable device companies are developing methods that can make reading as simple and unobtrusive as wearing a fitness bracelet- style device that takes measurements throughout the day—less stress, no cuffs.

Monitor blood pressure without a device

Dr Ghalib Janjua, a lecturer in electronic and electrical engineering at Robert Gordon University who specializes in bioengineering and device-free blood pressure monitoring, says there are already a number of monitoring solutions being researched and developed. They use a number of different metrics, including pulse arrival time, pulse transit time, pulse wave analysis, and pulse wave velocity.

However, Dr. Janjua cautions, “They all have limited accuracy and require frequent calibration against sphygmomanometer readings.” This means that while some devices can take readings without a cuff, you need a cuff device—a sphygmomanometer— to regularly check their accuracy.

Only recently have some of these methods been developed in ways that make blood pressure measurement without a cuff a practical option for all of us to perform at home. Most of them use the PPG sensor (that's photoplethysmography) that you can find on the underside of smartwatches like the Apple Watch or Fitbit Versa, which is usually used to track heart rate.

You'll find a number of different fitness trackers that claim to be able to use a PPG sensor to track your blood pressure. However, many are designed for rough estimates and are not certified medical devices, but are instead designed to monitor lifestyle, aiming to build a general picture of your overall health – without diagnosing serious problems. But all that could soon change.

One important example of the acceleration of this technology comes from a recent update to the Samsung Health Monitor app. This now allows you to use the PPG sensor already in your Samsung Galaxy Watch 3 or Galaxy Watch Active to read blood pressure. This is a spot check, which means you decide when you want to do it - it doesn't happen automatically. However, it should be compared with the cuff readings from time to time.

Rumors abound that other brands, including Fitbit and Apple, may introduce similar features soon. This could mean using data from PPG sensors, such as Samsung, or using similar technology such as a blood machine. For example in 2020 Apple register a patent , which describes how to measure blood pressure using wrist pressure sensors on a fitness bracelet.

The future of blood pressure monitoring technology

Can these technologies replace standard blood pressure monitors? The experts we spoke to were hopeful, but also cautious. "This is the beginning of a modernization of an age-old technology," says Dr Janjua. "This is an area that is showing encouraging results."

Blood pressure measurements with fitness bands and smartwatches have accuracy issues. This forces people to check the data further with a standard blood machine, and this makes the process more expensive. So don't throw away your cuffed blood pressure monitor just yet.

Source: https://www.techradar.com/news/are-wearables-the-future-of-blood-pressure-monitoring