Why Should Smartwatches Measure Blood Pressure?
This article was written by Karen Ng. Karen is a registered nurse with four years of experience in cardiac intensive care. She completed her master's at McGill and moved to Hong Kong to pursue a career in the field of health technology.
Why would someone want to track blood pressure (BP) throughout the day with a smartwatch? What health benefits could someone gain from having a wearable blood pressure monitor? To start answering these questions, we first look at home blood pressure monitors and how they have impacted the health of millions.
More and more people are buying home BP monitors as having high blood pressure (hypertension) becomes increasingly common. An aging population and urbanization have been cited as two reasons for this growing problem.1 Hypertension is an age associated disease, and as life expectancy rises so do conditions that appear with advancing age. Urbanization has changed many aspects of daily life1; driving, public transit and living in compact cities means less exercise. Furthermore, easy access to energy rich foods has changed diets considerably and the effects are now being observed in developing countries as they move towards urbanization1.
The World Health Organization (WHO) has called it a worldwide epidemic, estimating that 40% of adults aged 25 years and older have been diagnosed with high blood pressure.2 As a result, many people wanting to take a proactive stance in improving their health have bought home BP monitors.
Home blood pressure monitoring has health benefits
A weight scale is to someone who is working to lose weight as a home BP monitor is to someone trying to control their BP. It’s a tool to gauge progress and determine what is working and what needs to be optimized. Here are ways home BP monitoring (HBPM) have shown to be beneficial for hypertension management:
HBPM contributes to BP control
A scientific review of 18 randomized controlled trials have shown that those who do regular home BP monitoring have better control on their BP.3 Authors explained that feeling more engaged and responsible for their health, sticking to medication as well as frequent communication of results with doctors all contribute to this lowering effect.3
HBMP is used to identify white coat and masked hypertension
White coat hypertension is a common condition that causes BP to be elevated when measured in the doctor’s office but is normal if measured in a comfortable environment, such as the home. Masked hypertension is the opposite situation, in which normal BP is measured in the clinic but is consistently high at home. HBPM values help doctors decide what is the appropriate treatment for people with either white coat or masked hypertension.
HBPM can predict heart disease better than office BP values
To no surprise, several measurements done over a period of a few days in the comfort of one’s home is a better depiction of true average BP than a one-off measurement done in the clinic. This is proven in several studies concluding that home BP can more accurately determine whether someone is at risk for hypertension induced diseases better than office BP.4
The importance of home BP measurements is that it allows users to be actively aware of BP values through frequent measurements, and this aspect could be further enhanced with BP watches. Having the freedom to measure BP anywhere would motivate users to be more aware and act to control BP.
The drawbacks of home blood pressure monitors
Many expert committees have recommended the use of home BP monitors because of its positive influence on BP management. However, little innovation has surfaced for BP monitors since the early 80s when they came into market and they do come with user drawbacks.
Home BP monitors are in general, bulky machines that are not portable. Because of that, doing BP measurements anywhere but in the home, is not feasible. Users can’t capture how their BP fluctuates when they are out doing routine activities like going to work or sitting in traffic. Even if conventional BP monitors were used in public areas, the act of measuring BP is not discreet. The loud noise of the cuff inflating is enough to draw unwanted attention. Not to mention, for some people it is considerably uncomfortable or even anxiety provoking when the cuff inflates around the arm, which can induce higher BP values.
For others, often they simply forget to take BP at home or that they find it too troublesome to monitor every day. BP watches have the ability to overcome all of these obstacles. If watches and activity trackers could measure BP, then the issue of portability would be solved. Users could conveniently and almost unknown to anyone else, measure their BP anywhere, freeing them from the limitations of measuring at home. Having the power to take multiple measurements over a wide range of environments and activities can provide information about BP variability that was not possible before.
Is knowing how your BP changes in day important?
Scientists are starting to recognize the importance of stabilizing BP variability – the extent to which BP goes up and down over a period of time. Rather than only focusing on lowering average BP values, there may be more protection against heart disease in achieving hour-to-hour, day-to-day controlled BP values over time.5
Perhaps your BP at home is quite stable but in more stressful environments, like the workplace it is higher than average. At this point in time, there is no feasible way to track your BP several times a day in different environments easily and conveniently. BP watches could open a whole wealth of data for people to better understand what effects their BP and how to manage it better. This data could help doctors make better informed decisions when it comes to treatment of hypertension.
Increased awareness of heart health with BP watch
As stated earlier, the WHO reported that 40% of the world’s population is affected by hypertension. Even more shocking, approximately half of this population is aware they have the condition. In one large study, less than half (46.5%) out of 153 996 people across 17 countries were aware they had high BP.6
While rates of hypertension are increasing, the state of awareness and control still lags considerably. If BP watches became as widely used as current smart watches or activity trackers, people who only check their BP at the doctor’s office can be much more vigilant about their BP. This is especially true for younger generations, who don’t often think about their BP.
Hypertension is a worldwide epidemic and one of the biggest contributors to heart disease and mortality. Tech industries have an opportunity to make an important contribution to people’s awareness and control of high BP through development of wearable BP watches.
- Yusuf S, Reddy S, Ôunpuu S, Anand S. Global burden of cardiovascular diseases. Circulation. 2001 Dec 4;104(23):2855-64.
- World Health Organization (WHO. A global brief on hypertension: silent killer, global public health crisis.
- Cappuccio FP, Kerry SM, Forbes L, Donald A. Blood pressure control by home monitoring: meta-analysis of randomised trials. Bmj. 2004 Jul 15;329(7458):145.
- Council ES, Redon J, Narkiewicz K, Nilsson PM, Burnier M, Viigimaa M, Ambrosioni E, Coca A, Olsen MH, Schmieder RE, Tsioufis C. 2013 ESH/ESC Guidelines for the management of arterial hypertension. European Heart Journal. 2013;34:2159-219.
- Parati G, Ochoa JE, Lombardi C, Bilo G. Assessment and management of blood-pressure variability. Nature Reviews Cardiology. 2013 Mar 1;10(3):143-55.
- Chow CK, Teo KK, Rangarajan S, Islam S, Gupta R, Avezum A, Bahonar A, Chifamba J, Dagenais G, Diaz R, Kazmi K. Prevalence, awareness, treatment, and control of hypertension in rural and urban communities in high-, middle-, and low-income countries. Jama. 2013 Sep 4;310(9):959-68.